NEET Class 12 Biology MCQ – Environmental Issues

Question 1. Carbon monoxide is a major pollutant of 

  1. Water
  2. Air
  3. Noise
  4. Soil

Answer: 2. Air

Carbon monoxide (CO) is major pollutant in air, exhausted by various automobiles.

Question 2. Air pollution is caused by excess of 

  1. Dinitrogen
  2. Hydrogen
  3. Water vapour
  4. None of these

Answer: 1. Dinitrogen

Nitrogen form various oxides such as N2O, NO, NO N2O5, and N2O5 play an important role in the formation of photochemical smog and acid rains. Thus, excess of dinitrogen cause air pollution.

Question 3. Statements given below are pertaining to air pollutants.

  1. They cause injury to all living organisms.
  2. They reduce the growth and yield of crops and cause premature death of plants.
  3. They affect the respiratory system of humans and animals.

Choose the option containing the correct statements.

  1. 1 and 2
  2. 1 and 3
  3. 2 and 3
  4. 1, 2 and 3

Answer: 4. 1,2 and 3

  • All the given statements are correct as Air pollution has several effects on all living organisms and on climate. Diseases like bronchitis, lung cancer and emphysema are caused by air pollution.
  • NO2 causes bronchitis and lowers the resistance to influenza.
  • SO2 obstructs breathing and irritates the eyes.
  • Nitric acid, nitrous acid and sulphuric acid cause respiratory diseases. Air pollutants reduce the growth and yield of crops and cause premature death of plants.

Biology MCQs with answers for NEET

Question 4. The Air Prevention and Control of Pollution Act came into force in the year …A… It was amended in …B… to incorporate …C… as an air pollutant.

  1. A–1980, B–1986, C–water
  2. A–1981, B–1987, C–noise
  3. A–1982, B–1988, C–radioactive
  4. A–1983, B–1989, C–soil

Answer: 2. A–1981, B–1987, C–noise

Question 5. Which of the following is a primary pollutant?

  1. CO
  2. HNO3
  3. H2SO4
  4. O3

Answer: 1. CO

A primary pollutant is that which persists in the form in which it is released in the environment, e.g. CO.

Question 6. Assertion Secondary air pollutants are formed by interaction among the primary pollutants and are more toxic. Reason (R) DDT is a secondary air pollutant.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 3. A is true, but R is false

A is true, but R is false because Secondary air pollutants are produced photochemically from primary pollutants. Smog, photochemical smog, ozone and PAN all are secondary air pollutants. DDT is a primary soil pollutant.

Question 7. Which of the following is a secondary pollutant?

  1. CO
  2. O3
  3. SO2
  4. CO2

Answer: 2. O3

O3 (ozone) is a secondary pollutant. These are formed by the reaction of primary pollutants. CO is a quantitative pollutant. CO2 and SO2 are primary pollutants.

Biology MCQs with answers for NEET

Question 8. One of the following acts as a secondary pollutant.

  1. Br2
  2. CI2
  3. NO2
  4. HNO2

Answer: 3. NO2

Secondary pollutants are not emitted directly in the air, water or soil, but are synthesised by chemical reactions and the best examples are oxides of nitrogen. They further form ozone, PAN and aldehydes.

Question 9. The secondary pollutant which stops Hill reaction is 

  1. Sulphuric Acid
  2. Nitric Acid
  3. Peroxyacetyl Nitrate (Pan)
  4. Aldehydes
  5. None of the above

Answer: 3. Peroxyacetyl Nitrate (Pan)

PAN prevents the photolysis of water in photosynthesis or Hill reaction.

Question 10. Match the following columns.

NEET Biology Air Pollution and Noise Pollution Match the columns Q 40

Answer:

1–1, 2, 4

2–3, 5

Question 11. Match the following columns.

NEET Biology Air Pollution and Noise Pollution Match the columns Q 41

Answer:

1–3, 4, 5, 6, 7

2–1, 2, 8, 9

Question 12. Consider the following statements about pollution.

  1. Pollution is defined as an undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
  2. The Air (Prevention and Control of Pollution) Act was amended in 1987.
  3. The Environment Protection Act, of 1976 was formed to bring into effect the parameters of the United Nations Conference on the Human Environment.

Biology MCQs with answers for NEET

Choose the option containing the correct statements.

  1. 1 and 2
  2. 1 and 3
  3. 2 and 3
  4. 1, 2 and 3

Answer: 1. 1 and 2

Statements 1 and 2 are correct, but 3 is incorrect because In order to control environmental pollution, the government of India has passed the Environment Protection Act, 1986 to protect and improve the quality of our environment (air, water and soil). The air act was amended in 1987 to include noise as air pollution.

Question 13. Which of the following is a weightless pollutant?

  1. Sewage and exhaust emissions
  2. SO2 and NO2
  3. Photochemical smog
  4. Heat, sound and radioactive wastes

Answer: 4. Heat, sound and radioactive wastes

Heat, sound and radioactive wastes are weightless pollutants.

Question 14. A scrubber in the exhaust of a chemical industrial plant removes CBSE AIPMT, Karnataka CET

  1. Gases Like Sulphur Dioxide
  2. Particulate Matter Of The Size 5 Micrometer Or Above
  3. Gases Like Ozone And Methane
  4. Particular matter of the size 2.5 micrometre or less

Answer: 1. Gases Like Sulphur Dioxide

A scrubber can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime

Question 15. In the scrubber, the exhaust is passed through a

  1. Spray Of Water
  2. Spray Of Lime
  3. Both 1 And 2
  4. Spray Of Electrons

Answer: 3. Both 1 And 2

A scrubber can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime

Biology MCQs with answers for NEET

Question 16. Consider the following statements about scrubbers.

  1. It removes gases like sulphur dioxide from industrial exhaust.
  2. The exhaust passes through a spray of water or lime.
  3. Sulphur dioxide reacts with lime to form a precipitate of calcium sulphate and water dissolves gases.

Choose the option containing the correct statements.

  1. 1 and 2
  2. 1 and 3
  3. 2 and 3
  4. 1, 2 and 3

Answer: 4. 1,2 and 3

All the given statements are correct for the scrubber. A scrubber can remove gases like sulphur dioxide. In a wet scrubber, a fine spray of water or alkaline fluid like lime is allowed to fall over exhaust emissions. The particles also become heavy and fall down. The lime reacts with sulphur dioxide to produce a precipitate of calcium sulphate or calcium sulphide. Water is used to remove soluble gases and particles.

Question 17. The below diagram shows a scrubber. Identify A, B, C and D.

NEET Biology Air Pollution and Noise Pollution scrubber

  1. A–Particulate matter, B–Clean air, C–Dirty air, D–A dust particle
  2. A–Dirty air, B–Clean air, C–Water lime spray, D–Slurry outlet
  3. A–Slurry outlet, B–Dirty air, C–Particulate matter, D–Clean air
  4. A–Dust particle, B–Clean air, C–Particulate matter, D–Water spray

Answer: 2. A– Dirty air, B–Clean air, C–Water spray, D–Slurry outlet.

Question 18. Cyclone collectors are nowadays commonly used to control 

  1. Air Pollution With Special Reference To Dust Particles
  2. Radioactive Pollution
  3. Water Pollution In General
  4. Water pollution with special reference to Ganga Action Plan

Answer: 1. Air Pollution With Special Reference To Dust Particles

The cyclone collector is the device that is used for minimising air pollution by trapping the suspended particles like coarse dust generated due to activities like mining, cement and wood factories. These are dry scrubbers that work on the principle of inertia. Cyclone collector work similar to a centrifuge, but with a continuous feed of dirty air.

Thus, option 1 is correct.

Question 19. Gaseous pollutants can be controlled by

  1. Arrestors
  2. Electrostatic Precipitators
  3. Pyrolysis
  4. Incineration

Answer: 2. Electrostatic Precipitators

A gaseous pollutant can be controlled by Electrostatic Precipitator (ESP). It is an electrical device that removes particulate matter present in the exhaust of a thermal power plant. More than 99% of particulate matter can be removed by this method.

Question 20. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of 

  1. NOx
  2. SPM
  3. CO
  4. SO2

Answer: 2. SPM

The electrostatic precipitators are installed to control the emission of Suspended Particulate Matter (SPM) as these can cause various respiratory disorders in humans if released into the air.

Question 21. Which one of the following is the most efficient device to eliminate particulate matter from industrial emission?

  1. Cyclonic separators
  2. Trajectory separators
  3. Pyrolysis
  4. Incineration
  5. Electrostatic precipitator

Answer: 5. Electrostatic precipitator

An electrostatic Precipitator (ESP) is the most efficient device to eliminate submicron particulates from industrial emissions. It removes the impurities (dust, fibres) by applying a high-voltage electrostatic charge which precipitates the impurities on the charged plates.

Question 22. Which of the following is made use in an electrostatic precipitator?

  1. Catalysts
  2. Absorbers
  3. Electrodes
  4. Chemicals

Answer: 3. Electrodes

An electrostatic precipitator is used to remove particulate matter present in the exhaust of a thermal power plant. It has electrode wires that are maintained at several thousand volts which produce a corona that releases electrons.

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Question 23. In an electrostatic precipitator, very high voltage of electricity is passed through electrodes that produce a corona, which emits …A… . The dust particles present inside the precipitator gains a …B… charge instantly.

  1. A–electron, B–positive
  2. A–neutron, B–negative
  3. A–electron, B–negative
  4. A–proton, B–positive

Answer: 3. A–electron, B–negative

In an electrostatic precipitator, electrode wires are provided with an electric current of several thousand volts, which produces a corona that releases electrons (A). These electrons attach to dust particles and gives them a negative charge within a very small fraction of a second.

Question 24. Electrostatic Precipitator (ESP)

  1. Removes particulate matter from the exhausts of thermal power
    plants.
  2. It has a removal efficiency of 99%.
  3. ESP has thin wires and stack of thick metal plates.

Choose the option containing correct statements.

  1. 1 and 2
  2. 1 and 3
  3. 2 and 3
  4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All the given statements are correct.

Question 25. The below diagram shows an electrostatic precipitator. Identify A, B, C and D and select the correct option.

NEET Biology Air Pollution and Noise Pollution electrostatic precipitator

  1. A–Dust particles, B–Negatively charged wire, C–Discharge corona, D–Collection plate grounded
  2. A–Discharge corona, B–Collection plate grounded, C–Dust particles, D–Negatively charged wire
  3. A–Discharge corona, B–Negatively charged wire, C–Dust particles, D–Collection plate grounded
  4. A–Discharge corona, B–Dust particles, C–Negatively charged wire, D–Collection plate grounded

Answer: 3. A–Discharge corona, B–Negatively charged wire, C–Dust particles, D–Collection plate grounded

NEET Biology Air Pollution and Noise Pollution Electrostatic precipitator.

Question 26. Choose the correct statement regarding the catalytic converters.

  1. Vehicles fitted with catalytic converters must use leaded petrol
  2. Platinum, palladium and rhodium are used as catalysts in catalytic converters
  3. Catalytic converters reduce the particulate matter
  4. Nitrogen gas in the exhaust is converted to nitric oxide by the catalytic converter

Answer: 2. Platinum, palladium and rhodium are used as catalysts in catalytic converters

The statement in option 2 is correct. Other options are incorrect and can be corrected as Catalytic converters are fitted in vehicles for reducing the emission of poisonous gases. As the exhaust passes through, the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively.

Question 27. Catalytic converters are fitted into automobiles to reduce the emission of harmful gases. Catalytic converters convert leftover hydrocarbons into

  1. Carbon Dioxide And Water
  2. Carbon Monoxide
  3. Methane
  4. Carbon dioxide and methane

Answer: 1. Carbon Dioxide And Water

The statement in option 1 is correct. Other options are incorrect and can be corrected as Catalytic converters are fitted in vehicles for reducing the emission of poisonous gases. As the exhaust passes through, the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively.

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Question 28. Catalytic converters

  1. Fitted into automobiles for reducing emission of poisonous gases.
  2. Metals like platinum, palladium and rhodium are used as catalysts.
  3. On passing through a converter, the nitric oxide in the exhaust splits into nitrogen and oxygen. Carbon monoxide is oxidised to carbon dioxide.
  4. Leaded petrol is harmful to catalytic converters as they can inactivate the catalyst.

Choose the option containing correct statements about converters.

  1. 1, 2 and 3
  2. 2, 3 and 4
  3. 1, 3 and 4
  4. 1,2,3, and 4

Answer: 4. 1,2,3, and 4

All given statements are correct. Catalytic converters are fitted into automobiles for reducing the emission of poisonous gases. Rhodium and platinum, palladium are examples of catalysts used in catalytic converters. They convert unburnt hydrocarbons into CO2 and HO2 and CO and nitric oxide to CO2 and N2 gas, respectively. Use of unleaded petrol is however recommended as the lead petrol causes inactivation of the catalyst.

Question 29. Match the following columns.

NEET Biology Air Pollution and Noise Pollution Match the columns Q 59

Answer: 2. A–2, B–1, C–4, D–3

Question 30. Which of the following is not an air pollutant?

  1. NO2
  2. SO2
  3. Hydrocarbons
  4. CO2

Answer: 4. CO2

Carbon dioxide occurs naturally in the atmosphere. It is an essential ingredient in photosynthesis.

Thus, it is not an air pollutant.

NEET Biology Mcq Chapter Wise

Question 31. Air pollution causing photochemical oxidant production includes

  1. Carbon Monoxide, Sulphur Dioxide
  2. Nitrous Oxide, Nitric Acid Fumes, Nitric Oxide
  3. Ozone, Peroxyacetyl Nitrate, Aldehyde
  4. Oxygen, chlorine, fuming nitric acid

Answer: 3. Ozone, Peroxyacetyl Nitrate, Aldehyde

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

Question 32. Smog is a combination of

  1. Fire And Water
  2. Smoke And Fog
  3. Smoke And Water
  4. Air and water

Answer: 2. Smoke And Fog

Smog is basically derived from the merging of two words; smoke and fog. Smog occurs mainly because of air pollution and can also be defined as a mixture of various gases with dust and water vapour. Smog also refers to hazy air that makes breathing difficult.

Question 33. The basic component of smog may be

  1. PAN
  2. ozone
  3. PBN
  4. All of the above

Answer: 4. All of the above

Smog is a highly oxidising polluted atmosphere comprising O3, NO2, PAN (Peroxyacetyl Nitrate) and PBN (Peroxybenzoyl Nitrate).

Question 34. Smog is commonly formed due to JIPMER

  1. Mixing Of Ozone With NO2
  2. Deposition Of CO2 On Condensed Vapour Particles
  3. Greenhouse Effect And Global Warming
  4. The reaction of oxides of N and S, etc., with sunlight and volatile organic compounds

Answer: 4. Reaction of oxides of N and S, etc., with sunlight and volatile organic compounds

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

Question 35. Assertion Smog is commonly formed at places having low temperatures and high pollution of aerosol. Reason (R) It is very common in metropolis cities of India.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Smog is a common problem in many large urban areas, where human activity gives rise to particulates in the air. It can be exacerbated significantly by weather conditions and local geography, which can prevent particulate from being dispersed naturally by wind. It is more closely associated with automobile and industrial emissions, which interact frequently to create the particles that cause smog. Smog is the interaction of light with fine solid or liquid particles in the air, known as aerosols. The most common cause of photochemical smog is the interaction of nitrogen oxides and volatile compounds.

Question 36. Which are the primary constituents of photochemical smog?

  1. Carbon dioxide and NO2
  2. Hydrocarbons and CFCs
  3. SO2 and CO
  4. NO2 and hydrocarbons

Answer: 4. NO2 and hydrocarbons

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

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Question 37. Which is always present in photochemical smog?

  1. Ozone
  2. CO2
  3. SO2
  4. CH4

Answer: 1. Ozone

Ozone is generated in the lower atmosphere during the formation of photochemical smog when nitrogen dioxide splits to produce reactive oxygen atoms, which combine with molecular oxygen. Oxygen molecules split under ultraviolet radiations to produce oxygen atoms which combine with molecular oxygen to form ozone. It is always present in photochemical smog.

Question 38. Photochemical smog affects plants by

  1. Bleaching Of Leaves And Excess Production Of Pigments
  2. Shedding Of Foliage And Increase Of Transpiration
  3. Decolourising And Curling Of Leaves
  4. Degradation of chlorophyll by ozone

Answer: 4. Degradation of chlorophyll by ozone

Ozone is formed by resultant secondary pollutants in smog and degrades the photosynthetic pigments, i.e. chlorophyll of leaves.

Question 39. Choose the correct sequence of air pollution and its components with the effect it produces.

  1. Chemical factory → NO2 → ozone hole
  2. Automobile exhausts → NO2 → greenhouse effect
  3. Heavy industry → CO2 → acid rain
  4. Incinerators → NOx gases → photochemical smog

Answer: 4. Incinerators → NOx gases → photochemical smog

Nitrogen oxides are produced naturally through biological and non-biological activities. Human activity forms nitrogen oxides in the combustion process of industries, automobiles, incinerators and nitrogen fertilisers. Nitrogen oxides give photochemical smog. Thus, the correct sequence of air pollution and its component with the effect it produces is shown in option 4

Question 40. Match the following columns.

NEET Biology Air Pollution and Noise Pollution Match the columns Q 70

Answer: 4. A–3, B–2, C–1

Question 41. Burning of plastics releases

  1. CFC
  2. SO2
  3. Benzopyrene
  4. PCB

Answer: 4. PCB

Polychlorinated Biphenyls (PCB) are released from the burning of plastics.

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Question 42. The pollutants emitted by jet aeroplanes in the outer atmosphere are known as

  1. Smog
  2. Photochemical Oxidants
  3. Aerosols
  4. Loess

Answer: 4. Loess

Chemicals released in the atmosphere with force in the form of mist or vapours are called aerosols. Jet aeroplanes release aerosols which contain CFC.

Question 43. In the ‘wet system’ of removing gaseous pollutants

  1. Alkali Fluid Is Used
  2. Acidic Fluid Is Used
  3. Neutral fluid is used
  4. None of the above

Answer: 1. Alkali Fluid Is Used

In wet scrubbing processes for gaseous control, a liquid is used to remove pollutants from an exhaust stream. The removal of pollutants in the gaseous stream is done by absorption by the use of scrubbing reagents such as lime or sodium hydroxide (alkaline nature). Thus, the correct answer is 1.

Question 44. Which of the following statements is true?

  1. Benzene hexachloride is a non-biodegradable pollutant.
  2. Anthropogenic air pollutants are natural in origin.
  3. Carbon monoxide is a primary air pollutant.
  4. Sulphur dioxide causes brown air effects during traffic congestion in cities.

Choose the correct option.

  1. 1 and 3
  2. 1 and 2
  3. 2 and 3
  4. 2 and 4
  5. 1 and 4

Answer: 1. 1 and 3

Statements I and III are true, but II and IV are false because Non-biodegradable pollutants either do not degrade or degrade extremely slowly in the natural environment, e.g. DDT, BHC (Benzene Hexachloride). Anthropogenic pollutants are man made pollutants, e.g. sewage, pesticides, fertilisers, etc. Primary air pollutants are those which enter the air directly from the source, e.g. carbon monoxide. In traffic congested cities, the brown air effect is caused due to oxides of nitrogen.

Question 45. Which of the following is most poisonous?

  1. CO
  2. CO2
  3. C
  4. SO2

Answer: 1. CO

Carbon monoxide is produced due to incomplete combustion, metallurgical operations and naturally by plants as well as animals. CO combine with haemoglobin and produce carboxy haemoglobin. At 50 ppm carbon monoxide convert 7.5% of haemoglobin into carboxy haemoglobin. It impair oxygen transport resulting in giddiness, headache, decreased vision, cardiovascular malfunctioning and asphyxia. Thus, CO is most poisonous.

NEET Biology Mcq

Question 46. CO is more toxic than CO2 because 

  1. It Affects The Nervous System
  2. It Damages Lungs
  3. It Reduces The Oxygen Carrying Capacity Of Haemoglobin
  4. It forms acid with water

Answer: 3. It Reduces The Oxygen Carrying Capacity Of Haemoglobin

CO is more toxic because it reduces the oxygen carrying capacity of haemoglobin.

Question 47. According to the Central Pollution Control Board (CPCB), particles that are responsible for causing great harm to human health are of diameter 

  1. 2.5 micrometres
  2. 5.00 micrometres
  3. 10.00 micrometres
  4. 7.5 micrometres

Answer: 1. 2.5 micrometres

According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometres or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation inflammations and damage to the lungs and premature deaths.

Question 48. Examples of regional pollution are 

  1. Acid Rain
  2. Smog
  3. Both 1 and 2
  4. None of these

Answer: 3. Both 1 and 2

Regional pollutants are those which have been emitted from all sources in a region and have had time to mix, diffuse from their peak concentration and undergo physical, chemical and photochemical reactions. The size of a region is indeterminate, but usually incorporates one or more cities and is on the order of 100 to 10, 000 km2. Examples of regional pollution are acid rain, smog, etc.

Question 49. Rain is called acid rain when its pH is below

  1. 7
  2. 6.5
  3. 6
  4. 5.6

Answer: 4. 5.6

Acid rain refers to precipitation with a pH of less than 5.

Question 50. Acid rain is caused by increase in the atmospheric concentration of 

  1. CO2 and CO
  2. O2 and dust
  3. SO2 and NOv
  4. SO3 and CO

Answer: 3. SO2 and NO2

Acid rain is rainfall and other forms of precipitation with a pH of less than 5. Acid rain is caused by large scale emission of acidic gases into the atmosphere from thermal power plants, industries and automobiles. The common ones are sulphur dioxide, nitrogen oxides (NO2), Volatile Organic carbon (VOCs) and hydrogen chloride.

Question 51. The acid rain destroys vegetation because it contains

  1. Nitrates
  2. H2SO4
  3. O2
  4. CO

Answer: 2. H2SO4

Acid rain contains acidic components, such as sulphuric acid or nitric acid. The type of acid rain that contains water is called wet deposition. Acid rain formed with dust or gasses is called dry deposition. When these rain falls on the soil the soil become acidic. Also the leaves

Question 52. Acid rain occurs above the areas where 

  1. There Is Excess Production Of Nh3 And Coal Gas
  2. Factories Are Expelling SO2 In Air
  3. There Is an Excess Release Of CO2 Due To Increase In Combustion And Respiration
  4. Excess production of gaseous hydrocarbons

Answer: 2. Factories Are Expelling SO2 In Air

Acid rain occurs above the area where factories are expelling of sulphur dioxide into the air. These oxides react with water and precipitate in the form of the acid rain. For example, around the Taj Mahal the presence of the Mathura refinery has caused multiple events of acid rain.

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Question 53. In acid rain, sulphuric acid accounts for 

  1. 100% of acid
  2. 70% of acid
  3. 50% of acid
  4. 30% of acid

Answer: 2. 70% of acid

Acid rain is caused by a chemical reaction. Sulphur dioxide on reaction with water and oxygen forms sulphur trioxide which is rapidly converted into sulphuric acid in the presence of water. It accounts for 70% volume in acid rain. Hence, the correct answer is option 2.

Question 54. It is said that Taj Mahal is getting destroyed due to 

  1. Flood In Yamuna River
  2. Decomposition Of Marble As A Result Of High Temperature
  3. Air pollutant released from oil refinery of Mathura
  4. All of the above

Answer: 3. Air pollutant released from oil refinery of Mathura

Threat to Taj Mahal from the Mathura refinery is due to pollutant gases comprising SO2, H2S and nitrogen oxides. They would convert CaCO3 (marble) into calcium sulphate and calcium nitrate.

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Question 55. Which of the following is the most serious pollutant among sulphur compounds?

  1. Oxides of sulphur
  2. Carbonyl sulphide
  3. Carbon disulphide
  4. Sulphates

Answer: 1. Oxides of sulphur

Oxides of sulphur react with water in the atmosphere and form sulphuri cacid which cause rainwater to get acidic and thus oxides of sulphur cause acid rain. Carbonyl sulphide is a colourless gas which decomposes into carbon dioxide and carbon disulphide. Carbon disulphide is a colourless volatile liquid in its pure form. It is not considered to cause any type of pollution. Sulphates are polyatomic ions derived from sulphur and oxygen. Sulphates generally cause water pollution. So, the correct answer is oxides of sulphur.

Question 56. SO2 pollution affects 

  1. Nucleus
  2. Mitochondria
  3. Ribosome
  4. Vacuole

Answer: 2. Mitochondria

SO2 pollution affects the respiratory system mostly, thus it affects the mitochondria. Higher concentrations of SO2 can result in temporary breathing impairment for children and adults who are active outdoors. Short-term exposures of individuals to elevated SO2 levels while at moderate exertion may result in reduced lung function that may be accompanied by such symptoms as wheezing, chest tightness or shortness of breath.

Question 57. A component of living cell affected by pollutant SO2 is

  1. Nucleus
  2. All Cell Membrane Systems
  3. Cell wall
  4. None of the above

Answer: 2. All Cell Membrane Systems

The component of living cell affected by pollutant SO2 is cell membrane. SO2 replaces oxygen in cellular materials. It affects structural proteins in the membrane and these changes the membrane permeability.

Question 58. The ciliary passage of the respiratory tract gets damaged by

  1. Oxides Of Sulphur
  2. Oxides Of Nitrogen
  3. Oxides of carbon
  4. None of the above

Answer: 1. Oxides Of Sulphur

Oxides of sulphur irritate the respiratory epithelium and impair normal breathing or cause asthma. Thus, oxides of sulphur can damage ciliary passage of respiratory tract.

Question 59. Which of the following are the most suitable indicators of SO2 pollution in the environment?

  1. Algae
  2. Fungi
  3. Lichens
  4. Conifers

Answer: 3. Lichens

Lichens are very sensitive to SO2 pollution. They are completely destroyed at places where there is SO2 pollution in the atmosphere. Therefore, they act as very good indicators of SO2 pollution.

Question 60. SO2 of the atmosphere combines with water to form H SO2 4. When this reaches the soil

  1. It Increases Of Ph Of The Soil
  2. It decreases the pH of the soil
  3. pH remains the same
  4. Soil texture changes

Answer: 2. It decreases the pH of the soil

When sulphur dioxide combines with water and air, it forms sulphuric acid, which is the main component of acid rain. When the rain falls on the soil, the soil become acidic resulting in the lower pH of the soil.

Question 61. Which one of the following statements is incorrect in case of the Bhopal tragedy?

  1. Methyl isocyanate gas leakage took place
  2. Thousands of human beings died
  3. Radioactive fallout engulfed Bhopal
  4. It took place in the night of December 2/3, 1984

Answer: 3. Radioactive fallout engulfed Bhopal

All options are correct except option 3 because the Bhopal gas tragedy took place in the night of December 2/3, 1984, which was worst chemical disaster in history. People started dying within hours and more than 2000 lives were lost in first few days. Methyl isocyanate gas was the main chemical released that engulfed Bhopal that day.

Question 62. The effect of hydrogen sulphide on man leads to which of the following disease?

  1. Paralysis
  2. Sterility
  3. Blindness
  4. None of these

Answer: 4. None of these

HS2 does not accumulate in the body, but repeated/prolonged exposure to moderate levels can cause low blood pressure, headache, loss of appetite and weight. Repeated exposure over time to high levels of HS2 may cause convulsions, coma, brain and heart damage or even death. So, option 4 is correct.

Question 63. In 1984, Bhopal gas tragedy was caused due to leakage of 

  1. Potassium Isocyanate
  2. Methyl Isocyanate
  3. Sodium monoxide
  4. None of the above

Answer: 2. Methyl Isocyanate

Bhopal gas tragedy occurred on 2/3 December, 1984 in which a storage tank containing 36 tonnes of Methyl Isocyanate (MIC) burst in the pesticide manufacturing plant of Union Carbide in Bhopal. MIC is one of the deadliest toxins which when inhaled even in very small doses can kill the animal. It is highly irritating to skin, eyes or mucous membranes and causes death by lung oedema. It is also a carcinogenic agent.

Question 64. What were the effects of the Bhopal gas tragedy?

  1. Death of newborn babies
  2. Newborn babies were born with deformities
  3. Vegetation in the radius of 3.5 sq km around the Union Carbide factory was affected
  4. All of the above

Answer: 4. All of the above

Approximately 3598 deaths have resulted from the Bhopal Gas tragedy. Chronic inflammatory damage to the eye and lungs is the main cause. Other effects of this tragedy are the death of newborns and babies were born with deformities and the vegetation in the radius of 3.5 sq. km around the Union Carbide factory was affected.

Thus, option 4 is correct.

Question 65. The TLY (Threshold Limit Value) of methyl isocyanate responsible for the Bhopal gas tragedy is 

  1. 0.002 ppm
  2. 0.02 ppm
  3. 0.2 ppm
  4. 0.005 ppm

Answer: 2. 0.02 ppm

Methyl isocyanate is a volatile, toxic chemical used to manufacture carbamate pesticides. Bhopal gas tragedy (2/3 December 1984) is a case of air pollution in which MIC (Methyl Isocyanate) gas released from a fertiliser manufacturing plant of Union Carbide caused the death of approximately 3598 persons. MIC causes irritation in the eyes which may result in blindness, various lung diseases may result in death. Workers exposed to the MIC 8-hours threshold limit value of 0.02 ppm (46) are exposed to approximately 460 mg MIC in a workday.

Question 66. Various atmospheric air borne pollutants may cause

  1. Pneumonia
  2. Diarrhoea
  3. Respiratory Diseases And Allergies
  4. Cholera

Answer: 3. Respiratory Diseases And Allergies

Airborne pollutant enters via the respiratory tract in humans and cause respiratory diseases and allergies on the skin.

Question 67. Sulphur dioxide causes

  1. Emphysema
  2. Bronchitis
  3. Asthma
  4. All of the above

Answer: 4. All of the above

Sulphur dioxide causes respiratory tract diseases like asthma, bronchitis, cancer, emphysema, etc.

Question 68. Accumulation of fluoride in plant leaves causes

  1. Chlorosis
  2. Stem Rot
  3. Tip burn
  4. None of the above

Answer: 3. Stem Rot

Fluoride is an accumulative poison in plant foliage. Accumulation may be gradual over time and causes tip burn in leaves.

Question 69. Which of the following is pollution-related disorder?

  1. Silicosis
  2. Pneumoconiosis
  3. Fluorosis
  4. Leprosies

Answer: 1. Silicosis and 3. Fluorosis

(1 & 3) Fluorides are given out during the refining of metals. Fluorides cause fluorosis. This is a pollution-related disorder. When the level of fluoride content in drinking water becomes as high as 3-12 mg/L, the water becomes polluted. It affects teeth as well as bones. Silicosis is caused by inhalation of dust containing free silica or silicon dioxide, especially by workers engaged in mining, pottery, ceramic industry, sandblasting, and building and construction industries. So, both fluorosis and silicosis are pollution-related disorders.

Question 70. Bagassosis is

  1. Hypersensitivity Pneumonitis Due To Exposure To Fibrous Cellulose Part Of Crushed Sugarcane
  2. Is An Asthma Like Condition Produced Due To Exposure To Flax Or Cotton Fibres
  3. Hypersensitivity Pneumonitis Due To Exposure To Damp Hay Or Grain
  4. Hypersensitivity pneumonitis due to exposure to paprika

Answer: 1. Hypersensitivity Pneumonitis Due To Exposure To Fibrous Cellulose Part Of Crushed Sugarcane

Bagassosis is an interstitial lung disease, is a type of hypersensitivity pneumonitis due to exposure to the fibrous cellulose part of crushed sugarcane.

Question 71. Which of the following diseases is caused or aggravated by pollution?

  1. Bronchitis
  2. Rheumatism
  3. Scurvy
  4. Haemophilia

Answer: 1. Bronchitis

Inflammation of the lining of bronchial tubes causes bronchitis. Particulate matter, a prominent source of air pollution causes pneumoconiosis, byssinosis, emphysema, bronchitis and severe coughing. Rheumatism is a disease of joints. Scurvy is a deficiency disease caused due to the deficiency of vitamin C. Haemophilia is a genetic sex-linked disorder in which blood fails to clot normally.

Question 72. Black foot disease occurs due to 

  1. Cadmium
  2. Mercury
  3. Arsenic
  4. Copper

Answer: 3. Arsenic

Black foot disease is caused by excessive consumption of arsenic in water. Black foot disease, with gangrene-like symptoms, affects the feet and sometimes the fingers. It is a rare peripheral vascular disease found mainly in the Province of Taiwan (China). The best prevention for this disease is avoidance of exposure to arsenic by ingesting clean drinking water.

Question 73. ‘Knock knee’ syndrome occurs due to the pollution of 

  1. Nitrates
  2. Phosphates
  3. Fluorides
  4. Heavy metals

Answer: 3. Fluorides

Fluorides are given out during the refining of minerals (e.g. aluminium) and can contaminate groundwater. Excess fluorides in drinking water causes teeth deformity, hardened bones and stiff and painful joints (skeletal fluorosis) or knock knee disease.

NEET Biology MCQ Chapter Wise

Question 74. Black lung disease is common in

  1. Coal Miners Odisha Jee 2005
  2. Refinery Workers
  3. Petrochemical Industry
  4. Farmers

Answer: 1. Coal Miners Odisha Jee 2005

Black lung is a man-made, occupational lung disease that is contracted by prolonged breathing of coal mine dust. The disease is called ‘black lung’ because it causes the lungs to look black instead of pink. Medically, it is a type of pneumoconiosis called coal worker’s pneumoconiosis.

Question 75. Assertion Fluorides destroy vegetation. Reason (R) Fluorosis hinders respiration.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 3. A is true, but R is false

A is true, but R is false because, In plants, fluorides combine chemically with Mg 2+ of chlorophyll and hence inhibit photosynthesis. It causes the abscission of leaf and fruit and hence destroy vegetation. In human beings, the typical symptom of excess fluorine (fluorosis) is the mottling of teeth.

Question 76. In a small town, pasture is contaminated with airborne fluorides. Grazing animals in that area will suffer from

  1. Dental And Bone Diseases
  2. Goitre Disease
  3. Thyroid Disease
  4. Beriberi

Answer: 1. Dental And Bone Diseases

Fluorides cause fluorosis. It is a disease which is defined by mottling of teeth, and abnormal bones that are liable to fracture because fluorine replaces Ca²+ and makes the bones brittle. Fluoride is light airborne particulate matter.

Question 77. Fly-ash is a/an 

  1. Insectivorous Plant
  2. Light Airborne Particulate Matter
  3. New Name Of Orchid Plant
  4. Causal organisms of various diseases

Answer: 2. Light Airborne Particulate Matter

Fly ashes are finely divided residues resulting from the combustion of ground or powdered coal. It is discharged as an airborne emission. It is a light airborne particulate matter.

Question 78. Assertion COPD disease is very common in Kanpur. Reason (R) It is disease of respiratory tract occurring due to pollution.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Kanpur is the most polluted city in the country, with high quantities of Respirable Suspended Particulate Matter (RSPM) in the air according to the results of a survey carried out by the Central Pollution Control Board (CPCB) in 2002. Chronic Obstructive Pulmonary Disease (COPD) is a condition characterised by narrowing of the air ways, but these changes are permanent rather than reversible. COPD is caused by exposure to pollutant that produce inflammation.

Question 79. Fibrosis of lung is due to

  1. Asbestos And Cement Particles
  2. Mercury
  3. China Clay
  4. Rubber Particles

Answer: 1. Asbestos And Cement Particles

The asbestos and cement particles from industries are added to the air and these are inhaled by workers and people living nearby. These particles form a coating on the internal lining of lungs and bronchioles causing very serious fibrosis which may later lead to cancer.

Question 80. In silicosis, the silica particles can be seen

  1. As Needle Shaped Crystal By Light Microscopy
  2. As Needle Shaped Crystals Under Polarised Light
  3. As Maltese Cross Shaped Crystal By Light Microscopy
  4. As Maltese Cross Shaped Crystals Under Polarised Light

Answer: 2. As Needle Shaped Crystals Under Polarised Light

Silicosis is a lung disease caused by breathing-in tiny bits of silica. It is characterised by the fibrotic nodules with the concentric onion skinned arrangement of collagen fibres, central hyalinisation and a cellular peripheral zone with light birefringent particle seen under polarised light.

Question 81. Which of the following ailments is a result of inhalation of fine particulate matter?

  1. Irritation
  2. Inflammation
  3. Damage of lungs and premature deaths
  4. All of the above

Answer: 4. Damage of lungs and premature deaths

Fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage of the lungs and premature deaths.

Question 82. 3, 4-benzopyrene causes

  1. Leukaemia
  2. Cytosilicosis
  3. Lung Cancer
  4. Tuberculosis

Answer: 3. Lung Cancer

There are a number of chemicals, which causes lung cancer and one of them is 3,4-benzopyrene. Benzopyrene mutates three positions is the p53 gene, which leads to lung cancer. Hence, the correct option is 3.

NEET Biology MCQ Chapter Wise

Question 83. What is true about the Euro II norms? It is laid down to

  1. Control Sulphur At 350 Ppm In Diesel And 150 Ppm In Petrol
  2. Reduce Sulphur Level To 50 Ppm In Gasoline
  3. Reduce Sulphur Level To 200 Ppm In Diesel And Petrol
  4. Reduce sulphur level to 200 ppm in diesel and 100 ppm LPG

Answer: 1. Control Sulphur At 350 Ppm In Diesel And 150 Ppm In Petrol

Euro 2 norms were stipulated to control sulphur content at 350 ppm in diesel and 150 ppm in petrol and aromatic hydrocarbons are to be contained at 42%.

Question 84. All automobiles and fuel (petrol and diesel) were to have met the Euro III emission specification in eleven Indian cities from 1 April 2005 and have to meet the Euro IV norms by

  1. 1 April 2007
  2. 1 April 2008
  3. 1 April 2009
  4. 1 April 2010

Answer: 4. 1 April 2010

All automobiles and fuel were to have met the Euro III emission specification in eleven Indian cities from 1 April, 2005 and have to meet the Euro IV norms by 1 April 2010.

Question 85. Air (Prevention and Control of Pollution) Act was ammended in 1987 to include among pollutants

  1. Vehicular Exhaust Neet 2020
  2. Allergy Causing Pollen
  3. Noise
  4. Particulates of size 2.5 micrometers or below

Answer: 3. Noise

Air (Prvention and Control of Pollution) Act was ammended in 1987 to include noise as pollutant.

Question 86. Noise is

  1. Loud Sound
  2. Sound Of High Frequency
  3. Unwanted Sound
  4. Constant sound

Answer: 3. Unwanted Sound

Noise is defined as an undesired high level of sound. It is a physical form of pollution that affects the receiver directly. Noise or unwanted sound has a value of 80 dB and above.

Question 87. What is the intensity of sound in normal conversation?

  1. 10-20 dB
  2. 30-60 dB
  3. 70-90 dB
  4. 120-150 dB

Answer: 3. 70-90 dB

The unit of sound level is decibel. Moderate conversation produces 30–60 dB sound.

NEET Biology MCQ Chapter Wise

Question 88. During day time sound level in the silent zone is about 

  1. 20 dB
  2. 30 dB
  3. 40 dB
  4. 50 dB

Answer: 4. 50 dB

Sound is expressed in decibels (dB). A decibel is one-tenth of bel, a unit of measuring electric or acoustic power. The World Health Organisation (WHO) has recommended a noise of less than 75 decibels for industries. The National Pollution Control Board has recommended the following maximum permissible noise level in Indian cities

NEET Biology Air Pollution and Noise Pollution National Pollution Control Board

Question 89. Noise pollution is measured in

  1. Decibels
  2. Amperes
  3. Fathoms
  4. Ohm

Answer: 1. Decibels

Noise pollution is measured in decibels (dB).

Question 90. Sound above what level is considered hazardous noise pollution?

  1. Above 80 dB
  2. Above 120 dB
  3. Above 150 dB
  4. Below 30 dB

Answer: 1. Above 80 dB

Sound above 80 dB becomes hazardous to humans.

Question 91. Consider the following statements regarding noise.

  1. Causes psychological disorders in humans.
  2. Causes physiological disorders in humans.
  3. Unit of measurement of noise dB.
  4. 150 dB is tolerable for humans.

Choose an option containing correct statements.

  1. 1 and 4
  2. 1 and 2
  3. 1, 2 and 3
  4. 1 and 3

Answer: 3. 1,2, and 3

All statements are correct except IV because Noise pollution causes psychological and physiological disorders in humans. Noise is measured in dB unit. Above 80 dB noise became hazardous for human.

Question 92. The green muffler is used against which type of pollution?

  1. Air
  2. Soil
  3. Water
  4. Noise

Answer: 4. Noise

Green plants are being planted along road side to check noise pollution. This is known as green muffler.

Question 93. The anxiety and stress reactions are caused by 

  1. Air Pollution
  2. Noise Pollution
  3. Water Pollution
  4. Nuclear pollution

Answer: 2. Noise Pollution

NEET Biology MCQ Chapter Wise

Noise pollution has several adverse effects on human health as The first effects of noise are anxiety and stress however, in extreme cases it may lead to fright. Noise causes headache by dilating blood vessels of the brain, eye strain by dilating the pupil, digestive spasms through anxiety and high blood pressure by increasing cholesterol level in the blood. Noise can impair the development of nervous system of unborn babies which leads to abnormal behaviour in later life.

Question 94. Assertion Inhabitants close to very busy airports are likely to experience health hazards. Reason (R) Sound level of jet aeroplanes usually exceeds 160 dB.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Noise level up to 65 dB (decibel) in a commercial area and up to 75 dB in industrial areas is permitted as per law. Prolonged exposure to noise level to 80 dB or more leads to loss of hearing ability, fatigue, nervousness, fever, hypertension, gastric disorder, increase in cholesterol level and dilation of pupil of the eye. As the jet aeroplanes have the noise up to 150-160 dB or more, the inhabitants in the vicinity of busy airports are likely to experience above health hazards. Maximum noise level is recorded in rockets, i.e. 180 dB.

Question 95. Which of the following physiological manifestations is the result of noise pollution?

  1. Dilation of pupil
  2. Increase in the rate of heartbeat
  3. Constriction of blood vessels
  4. All of the above

Answer: 4. All of the above

Because of noise pollution nervous tension, blood pressure and heart trouble increases. It causes constriction of blood vessels and increases the rate of heartbeat. Noise pollution also increases digestive spasms and causes the dilation of the pupils of the eyes. It causes impairment of night vision and decreases the rate of colour perception.

NEET Biology Notes – Environmental Issues

Environmental Issues Introduction

Human population size has grown enormously over the last hundred years with increase in demand for food, water, home, electricity, roads, automobiles, and numerous other commodities; and exerting tremendous pressure on our natural resources, along with contributing to the pollution of air, water, and soil. The need is to check the degradation and depletion of natural resources and pollution without halting the process of development.

Any undesirable change of the physical, chemical, or biological characteristics in the atmosphere, lithosphere, and hydrosphere which is harmful to man directly or indirectly is called pollution.

Kinds Of Pollution

  • On the basis of part of environment where it occurs most
    • Air pollution
    • Water pollution
    • Soil pollution
  • On the basis of origin
    • Natural: Examples are volcanic eruptions; release of CH4 by paddy fields and cattle; release of CO by plants and animals; emission of natural gas, O3, nitrogen oxides, cosmic rays, and UVrays; etc.
    • Anthropogenic (man-made): Examples are burning of fossil fuels, deforestation, mining, sew- age, industrial effluent, pesticides, fertilizers, etc.
  • On the basis of physical nature of pollutants
    • Gaseous pollution
    • Dust pollution
    • Thermal pollution
    • Noise pollution
    • Radioactive pollution, etc.

Read and Learn More NEET Biology Notes

Pollutants

  • Non-biodegradable: DDT, BHC, waste plastic bottles, polyethylene bags, used soft drink cans, etc.
  • Biodegradable: Sewage, market garbage, livestock wastes, etc.
  • Primary pollutant: CO and DDT.
  • Secondary pollutant: Nitrogen oxides and hydrocarbons react photochemically to produce peroxyacyl nitrates and O3.
  • Qualitative: Insecticides, weedicides, and fungicides.
  • Quantitative: CO, CO2, NO, and NO2.

Air Pollution

Fifty-two percent of air pollution is caused by CO, 18% by SO2, 12% by hydrocarbons, 10% by particulates, 6% by nitrogen ox- ides, and 2% by the remaining matter.

Primary Air Pollutants

  • Particulate matter
    • Settleable: Diameter is 10 mm and settles out in less than a day.
    • Suspended: Diameter is 1 mm and can remain suspended for weeks. Examples are aerosol, dust, mist, and fly ash.
      Suspended particulate matter (SPM) (particularly of size 2.5 g or less) in troposphere causes and aggravates human respiratory illness such as asthma, chronic bronchitis irritation, and premature death. SPM in stratosphere alters the radiation and thermal budgets of the atmosphere, lowering the temperature at the earth’s surface.
  • Carbon monooxide: It is a product of incomplete combustion of fossil fuels. 50% emissions are from automobiles. It produces COHb (carboxyhemoglobin) and reduces oxygen carrying capacity of blood, resulting in giddiness, decreased vision, headache, cardio- vascular malfunction, and asphyxia.
  • Hydrocarbons (HCs) or volatile organic carbons (VOCs): These are produced naturally (c.g., CH4) or due to incomplete combustion. Benzene and HCHO are carcinogenic and cause irritation of eyes and mucous membrane and bronchial constriction. HCHO leads to indoor pollution.
  • SO2: It is produced during the combustion of sulfur containing fossil fuels and smelting of ore from oil refineries. It causes eye irritation, severe respiratory problems, inhibits ETS in plants, and is also responsible for classical smog (London smog or sulfurous smog) and stone cancer.
  • Nitrogen oxides (NO): These are mainly produced during the combustion of fossil fuels at high temperature in automobile engines. Nitrogen oxides cause brown air that leads to heart and lung problems.

Secondary Air Pollutants

Secondary air pollutants are formed through reaction between primary pollutants and often are more toxic.

  • Photochemical smog (Los Angeles smog): It is a pollutant and is related to smog and fog.
  • Acid rain: Sulfur dioxide and nitrogen oxide cause pollution by increasing acidity. Sulfuric acid is present in acid rain.

Air Pollution and Its Control

There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator. It can remove over 99% particulate matter (PM) present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles giving them a net negative charge.

The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall. A scrubber can remove gases such as sulfur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime.

Recently, we have realized the dangers of particulate matter that are very-very small and are not removed by these precipitators. According to Central Pollution Control Board (CPCB), particulates of size 2.5 μm or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage to the lungs, and premature deaths.

NEET Biology Environmental Issues Electrostatic precipitator

Catalytic converter has expensive metals such as platinum and palladium and can convert NO, to nitrogen and CO to CO2.

Controlling Vehicular Air Pollution: A Case Study of Delhi

Delhi leads the country in its levels of air-pollution-it has more cars than the states of Gujarat and West Bengal put together. In the 1990’s, Delhi ranked fourth among the 41 most polluted cities of the world. Air pollution problems in Delhi became so serious that a public interest litigation (PIL) was filed in the Supreme Court of India.

After being censured, the government was asked to take, within a specified time period, appropriate measures, including switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG). All the buses of Delhi were converted to run on CNG by the end of 2002. CNG has the following advantages:

  • It burns most efficiently.
  • It is cheaper than petrol or diesel.
  • It cannot be siphoned off by thieves and adulterated like petrol or diesel.
  • The main problem that government faced was the difficulty of laying down pipelines to deliver CNG through distribution points/pumps and ensuring uninterrupted supply.
  • The use of unleaded petrol, low-sulfur petrol and diesel, and catalytic converters in vehicles; the application of stringent pollution-level norms for vehicles; etc., are the steps taken to reduce pollution.
  • Stringent norms for fuels were given in the new auto fuel policy for steadily reducing the sulfur and aromatics content in petrol and diesel fuels. Euro II norms, for example, stipulate that sulfur be controlled at 350 parts-per-million (ppm) in diesel and 150 ppm in petrol. Aromatic hydrocarbons are to be contained at 42% of the concerned fuel. The goal, according to the roadmap prepared by the Indian Government, is to reduce sulfur to 50 ppm in petrol and diesel and bring down the level to 35%. Vehicle engines will also need to be upgraded.
  • The Bharat Stage II (equivalent to Euro-II norms), which is currently in place in Delhi, Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Ahmadabad, Pune, Surat, Kanpur, and Agra, is applicable to all automobiles throughout the country since April 1, 2005.
  • All automobiles and fuels petrol and diesel-were to have met the Euro-3 emission specifications in these 11 cities from April 1, 2005, and the Euro-4 norms by April 1, 2010. The rest of the country has Euro-3 emission norm compliant automobiles and fuels since 2010.
  • A substantial fall in CO2 and SO2 levels has been found in Delhi between 1997 and 2005.

Water Pollution

Water pollution is the adverse change in the composition or condition of water such that it becomes less suitable for the purposes for which it would be suitable in its natural state.

Sources

  • Point sources (e.g., sewage outlet of a municipal area or effluent outlet of a factory)
  • Non-point sources (e.g., city storm water flow and agriculture runoff)

Pollutants

Various types of pollutants are as follows:

  • Biological
  • Chemical
  • Physical
    • Household detergents
    • Domestic sewage
    • Industrial wastes
    • Offshore oil drilling
    • Thermal power plants
    • Pollution of detergents in water: It prevents the decomposition of organic compounds as it forms a thin film around them due to its low surface tension (surfactant nature). This results in the ac- cumulation of organic substances in water. There- fore, detergents are also called builders.

Effects

  • Decreasing of dissolved O2 (DO or dissolved oxygen) content of water bodies.
  • Higher biological oxygen demand (BOD): BOD is the amount of O2 in milligrams required to decompose organic matter present in 1 L water kept at temperature of 20°C for 5 days. If it is 4090 mg/L, then water is heavily polluted.
  • COD (chemical oxygen demand): It indicates total O2 requirement of all O, consuming pollutant materials present in water. Its value is higher than BOD.
  • Annelid worm Tubifex and some insect larvae act as indicator species for polluted waters.
  • Persistent pesticides (e.g., DDT) and mercury pass into the food chain. Their increase in amount per unit weight of organism with the rise in trophic level is called biological magnification.
  • Biomagnification of DDT causes hemorrhage, softening of brain, liver cirrhosis, hypotension, etc.

NEET Biology Environmental Issues Biomagnification of DDT in aquatic food chain

  • Eutrophication is increase in the amount of nutrients in water due to detergents, pesticides, etc. It leads to organic loading, depletion of O2, etc.
  • Minamata disease is caused due to mercury in water.

NEET Biology Environmental Issues Composition of waste water

A Case Study of Integrated Waste Water Treatment

  • Waste water including sewage can be treated in an integrated manner. An example of such an initiative is the town of Arcata (California).
  • The town’s people created an integrated waste water treatment process within a natural system in collaboration with Humboldt State University.
  • The cleaning occurs in two stages:
    • The conventional sedimentation, filtering, and chlorine treatments are given. But after this stage, dissolved heavy metals still remain.
    • Biologists developed a series of six connected marshes over 60 ha of marshland. Appropriate organisms were seeded into this area, which neutralize, absorb, and assimilate the pollutants. Hence, as the water flows through the marshes, it gets purified naturally; marshes also constitute a sanctuary.
  • Friends of the Arcata Marsh (FOAM) are responsible for the upkeep and safeguarding of this wonderful project.
  • Ecological sanitation is a sustainable system for handling human excreta using dry composting toilets. This is a practical, hygienic, efficient, and cost-effective solution by which human excreta can be recycled into a resource (as natural fertilizer), which reduces the need for chemical fertilizers. There are working “ecosan” toilets in many areas of Kerala and Sri Lanka.

Solid Waste

  • Solid wastes refer to everything that goes out in trash.
  • Sanitary landfills were adopted as the substitute for open-burning dumps wherein sanitary landfill wastes are dumped in a depression or trench after compaction and covered with dirt every day.
  • But these sites are getting filled too and the seepage of chemicals, etc., from these landfills pollutes underground water resources.
  • Anthropogenic waste is categorized into three types: (a) bio-degradable, (b) recyclable, and (e) non-biodegradable.
  • Polyblend, a fine powder of recycled modified plastic, was developed by the company owned by Ahmed Khan in Bangalore. This mixture is mixed with bitumen, which is used to lay roads. Blends of polyblend and bitumen, when used to lay roads, enhanced bitumen’s water repellant properties and helped to increase road life by a factor of three.
  • The use of incinerators is crucial for the disposal of hospital waste.
  • Irreparable computers and other electronic goods are known as electronic wastes (e-wastes). e-wastes are buried in landfills or incinerated. Over half of the e-wastes generated in the developed world are exported.
  • Developing countries such as China, India, and Pakistan import over half of the e-waste generated by developed countries for the recovery of metals such as copper, iron, silicon, nickel, and gold.
  • Recycling is the only solution for the treatment of e-wastes, provided it is carried out in an environment-friendly manner.

Soil Pollution

  • Soil pollution is the alteration in soil caused by the removal or addition of substances and factors which decrease its productivity and the quality of plants and ground water.
  • Non-biodegradable materials such as polyethylene carry bags, waste plastic sheets, and bottles persist in soil for long periods.
  • Hospital wastes also cause soil pollution.
  • Excessive use of fertilizers causes soil deterioration and decreases the natural microflora.
  • Mine dust destroys top soil and contaminates the area with toxic metals and chemicals.
  • Recycling of solid wastes, burning of waste, utilizing heat to warm residential units, and generation of electricity is the best way to control soil pollution.
  • Incineration (burning in the presence of O2 at 1200°C) and pyrolysis (combustion in the absence of O2 at 1650°C) methods can be used to eliminate solid wastes.
  • Soil erosion and overgrazing are negative pollution.

Case Study of Organic Farming

Integrated organic farming is a cyclical, zero-waste procedure, where waste products from one process are cycled as nutrients for other processes. This allows the maximum utilization of resources and increases the efficiency of production. Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, is doing just this. He includes bee-keeping, dairy management, water harvesting, composting, and agriculture in a chain of processes, which support each other and allow an extremely economical and sustainable venture.

There is no need to use chemical fertilizers for crops, as cattle excreta (dung) are used as manure. Crop waste is used to create compost, which can be used as a natural fertilizer or can be used to generate natural gas for satisfying the energy needs of the farm. Enthusiastic about spreading information and help on the practice of integrated organic farming, Dagar has created the Haryana Kisan Welfare Club, with a cur- rent membership of 5000 farmers.

Global Environment Change

CO2, CH4, N2O, and CFCs are radiatively active gases (also called greenhouse gases). The increased amounts of these gases in atmosphere are affecting the global climate. This phenomenon is known as global climatic change.

Greenhouse Gases and Global Warming

  • The term “greenhouse effect” was coined by Arrhenius.
  • Greenhouse gases trap the long-wave radiations. A part of this energy is re-radiated back to the surface of the earth. The downward flux of long-wave radiations by greenhouse gases is called greenhouse flux.
  • The phenomenon of keeping the earth warm due to the presence of certain radiatively active gases in the atmosphere is called greenhouse effect, without which the average temperature of the earth would have been -18°C-20°C rather than the present average of 15°C.

NEET Biology Environmental Issues Relative contribution of different greenhouse gases to global warming

  • The excessive increase in the concentrations of these gases in the atmosphere would retain more and more infrared radiation, resulting in enhanced greenhouse effect.
  • CFC is the most effective greenhouse gas (effectiveness is 14,000 times more than CO2).

Effects of Greenhouse Gases

  • CO2 fertilization effect: An increase in the atmospheric concentration of CO2 increases the productivity of C3 plants and decreases the rate of transpiration due to partial stomatal closure.
  • The possible effects of global warming are as follows:
    • Increasing of global temperature (increased 0.6°C, most of it during the last three decades) and more extreme climatic conditions (El Nino effect).
    • Warming of troposphere and cooling of stratosphere and thermosphere.
    • Melting of ice caps.
    • Rising of sea level; changes in rainfall pattern.
    • Global warming will push tropics into temperate areas and temperate areas towards pole (shifting of climatic zones) and higher altitudes in mountains resulting in changed species distribution.
  • Control measures: Reduced deforestation, cutting down use of fossil fuels, planting trees, and slowing down population growth.
  • Ozone depletion
    • Ozone layer is present in stratosphere at an altitude of 23-25 km (conc. 0.3 ppm). It acts as shield against UV radiation.
    • A large hole has appeared in the ozone shield over Antarctica and a smaller one over North Pole (discovered by Farman in 1985).
    • Ozone is commonly called chemical weed.
    • CFC, CH4, CCl4, halogens, and N2O cause the destruction of O3. These are ozone depleting substances (ODS).
    • CFCs are the most damaging. These release Cl atoms in the stratosphere which destroy O3.
    • Thinning of the ozone layer results in an increase in the UV-B radiation.
    • UV-B causes snow blindness.
    • Nowadays, CFCs are being replaced by hydro- fluorocarbons (HFCS) and hydrochlorofluorocarbons (HCIFCs).

Radioactive Wastes

  • The use of nuclear energy has two very serious inherent problems. The first is accidental leakage, as occurred in the Three Mile Island and Chernobyl incidents and the second is safe disposal of radioactive wastes.
  • It causes mutations to occur at a very high rate. At high doses, nuclear radiation is lethal but at lower doses, it creates various disorders, the most frequent of all being cancer.
  • It has been recommended that the storage of nuclear waste, after sufficient pre-treatment, should be done in suitably shielded containers buried within the rocks, about 500 m deep below the earth’s surface.

Degradation By Improper Resource Utilities And Maintenance

Soil Erosion and Desertification

  • The fertile top-soil formation takes centuries. But it can be removed very easily due to human activities such as over-cultivation, unrestricted grazing, deforestation, and poor irrigation practices, resulting in arid patches of land. These barren patches extend and meet over time and create a desert.
  • Desertification is becoming a major problem, particularly due to increased urbanization.

Water-logging and Soil Salinity

Water Logging

Water logging means a kind of physiological dry soil in which water is present but not available from plants.

Soil Salination

Soil salination is increase in the concentration of salts in a soil. It may develop due to the following reasons:

  • The formation of soil from rocks having salts.
  • Poor drainage and elevated water table.
  • Nearness to sea.
  • Continuous addition of fertilizers, etc.

Water logging and soil salinity are some of the problems that have come in the wake of the Green Revolution.

Noise Pollution

Noise pollution is that form of sound energy which is not appreciated by human ears, i.e., it is undesired high level of sound.

  • The frequency of sound is measured in hertz (Hz) while the unit of sound is decibel (dB).
  • Moderate conversation = 60 dB
    Loud conversation = 70 dB
    Scooter = 30 de
    Truck/bus = 90 dB
    Jet aeroplane 150 dB
    Rocket = 180 dB
  • Zone-wise permissible ambient noise levels are given in Table 16.2 (according to the Central Pollution Control Board).
  • Green Muller scheme: It is growing of trees and shrubs in rows around the noisy area and road-sides to reduce intensity.

NEET Biology Environmental Issues Green Muller scheme

Effects of Noise Pollution

  • A regular exposure to sound of 80 dB reduces hearing by 15 dB in 10 years.
  • A sudden high intensity noise can damage ear drums.
  • Noise pollution leads to anxiety, stress, insomnia, emotional disturbance, and hypertension.

Deforestation

  • Deforestation is the conversion of forested areas to non-forested ones. It is estimated that almost 40% forests have been lost in the tropics, compared to only 1% in the temperate region.
  • At the beginning of the 20th century, forests covered about 30% of the land of India. By the end of the century, it shrunk to 19.4%, whereas the National Forest Policy (1988) of India has recommended 33% forest cover for the plains and 67% for the hills.
  • Trees are axed for timber, firewood, cattle ranching, and several other purposes. Slash-and-burn agriculture, commonly called as Jhum cultivation in the north-eastern states of India, has also contributed to deforestation.
  • One of the major effects is enhanced carbon dioxide concentration in the atmosphere. It also causes loss of biodiversity due to habitat destruction, disturbs hydrologic cycle, causes soil erosion, and may lead to desertification in extreme cases.
  • Reforestation is the process of restoring a forest. It may also occur naturally in a deforested area.

Case Study of People’s Participation in Conservation of Forests

  • A Bishnoi woman of Khejarli village, Jodhpur, Rajasthan, named Amrita Devi showed exemplary courage by hugging a tree.
  • The Amrita Devi Bishnoi Wildlife Protection Award is given to individuals or communities from rural areas that have shown extraordinary courage and dedication in protecting wildlife.
  • Chipko Movement: It is the movement which was initially meant for protecting trees and not for the preservation of environment including habitat and wildlife. The Chipko Movement was born in March, 1973, in Gopeshwar in Chamoli district. The movement has two leaders: Chandi Prasad Bhatt of Gopeshwar and Sunder Lal Bahugana of Silyara in Tehri region. A similar movement was undertaken by Pandurang Hedge in the South. It is known as the Appiko Movement.
  • The Government of India in 1980’s introduced the concept of joint forest management (JFM).

 

Assertion-Reasoning Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).

  1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).
  2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
  3. If Assertion is true but Reason is false, then mark (3).
  4. If both Assertion and Reason are false, then mark (4).

Question 1. Assertion: Euro 2 norms are framed to reduce the content of CO and aromatic compounds from fuels.

Reason: These compounds lead to reduced visibility and carboxyhemoglobin formation.

Answer. 4. If both Assertion and Reason are false, then mark (4).

Question 2. Assertion: Sewage discharge in a water body causes eutrophication.

Reason: This increases the organic content in water body and, hence, the growth of algal blooms.

Answer. 2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).

Question 3. Assertion: Biomagnification of DDT can enhance the de- cline in bird population.

Reason: DDT causes thinning of egg shell and their premature breaking by disturbing calcium metabolism.

Answer. 1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

Question 4. Assertion: Ecological sanitation is a sustainable system for handling human excreta.

Reason: It is a practical and hygienic method of using dry composting toilets.

Answer. 1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

Question 5. Assertion: El Nino is a climatic change which causes deleterious environmental changes.

Reason: Increased tropospheric ozone due to El Nino causes shift of climatic regions.

Answer. 3. If Assertion is true but Reason is false, then mark (3).

NEET Biology Multiple Choice Questions – Environmental Issues

Environmental Issues Multiple Choice Questions

Question 1. Euro-2 (April 2000) is the emission norm for reducing

  1. O3 and CO
  2. NO2 and N2O
  3. Sulfur and aromatic hydrocarbons
  4. CO4 and particulate matter

Answer. 3. Sulfur and aromatic hydrocarbons

Question 2. Corrosion of Taj Mahal is due to the conversion of CaCO3 into

  1. CaSO4 and CaNO3
  2. Ca(OH)2
  3. CaO
  4. All of these

Answer. 1. CaSO4 and CaNO3

Question 3. ____________ is highly hazardous to animal health but on plants, this gas does not seem to show adverse effect.

  1. CO
  2. CO2
  3. SO2
  4. NO2

Answer. 1. CO

Question 4. The most effective greenhouse gas is

  1. CFC
  2. CO2
  3. Methane
  4. O2

Answer. 1. CFC

Question 5. Acid rain is due to

  1. 03, PAN
  2. Oxides of nitrogen and sulfur
  3. Greenhouse effect
  4. All of these

Answer. 2. Oxides of nitrogen and sulfur

Question 6. Pollutant responsible for causing phaeophytization is

  1. SO2
  2. NOX
  3. CO2
  4. Aeroallergens

Answer. 1. SO2

Question 7. Greenhouse gases are

  1. Absorbers of long-wave radiations from the earth
  2. Transparent to both solar radiations and long-wave radiations from the earth
  3. Absorbers of solar radiations for warming the atmosphere
  4. Transparent to emissions from the earth for passage into outer space

Answer. 1. Absorbers of long-wave radiations from the earth

Question 8. Ultraviolet radiations produce the photo oxidant

  1. SO2
  2. Flouride
  3. CO
  4. 03

Answer. 4. 03

Question 9. Major air pollutant is

  1. CO2
  2. N2
  3. CO
  4. S

Answer. 3. CO

Question 10. The products resulting from the atmospheric rea tions of hydrocarbons and nitrogen oxides in the presence of sunlight are called

  1. Primary pollutants
  2. Secondary pollutants
  3. Tertiary pollutants
  4. Non-pollutants

Answer. 2. Secondary pollutants

Question 11. Which of the following is a reddish-brown pollutant gas?

  1. NO
  2. N2O
  3. NO2
  4. NH3

Answer. 3. NO2

Question 12. Acid rain

(a) Causes necrosis

(b) Convert chlorophyll-a into pheophytin

(c) Responsible for the formation of PAN

  1. Only (a) and (b) are correct
  2. Only (b) and (c) are correct
  3. Only (a) is correct
  4. Only (c) is correct

Answer. 1. Only (a) and (b) are correct

Question 13. Which is not an effect of global warming?

  1. More extreme weather condition.
  2. Poleward shifting of organism.
  3. Rise of sea level.
  4. Good fungal growth in soil.

Answer. 4. Good fungal growth in soil.

Question 14. Which of the following conference obtained commitments from different countries for reducing overall greenhouse gas emission at a level 5% below 1990 level by 2008-2012?

  1. Kyoto Protocol, 1997
  2. Earth Summit, Rio-de-Janeiro, 1992
  3. Montreal Protocol, 1987
  4. Helsinki Declaration, 1989

Answer. 1. Kyoto Protocol, 1997

Question 15. Which plant has the maximum power of absorbing CO2 and oxides of nitrogen in a polluted area?

  1. Eucalyptus
  2. Coleus indica
  3. Robinia pseudoacacia
  4. Daucus carota

Answer. 3. Robinia pseudoacacia

Question 16. Arrange CFC, CH4, N2O, and CO2 in decreasing order according to their contribution in greenhouse effect:

  1. CO2 > N2O > CFC > CH4
  2. CFC > CO2 > CH4> N2O
  3. CH,>CFC>N,O>CO,
  4. CO, >CH_>CFC>N,O

Answer. 4. CO, >CH_>CFC>N,O

Question 17. Which is not a natural source of CH, in the environment?

  1. Biomass burning
  2. Termites
  3. Gut of ruminants
  4. Rice fields

Answer. 1. Biomass burning

Question 18. The controlled aerobic combustion of wastes inside chambers at temperature of 900-1300°C is known as

  1. Incineration
  2. Recycling
  3. Pyrolysis
  4. Sanitary dumping

Answer. 1. Incineration

Question 19. Aerosol is a suspension of

  1. Liquid or solid particles of more than 1 mm
  2. Liquid drops in air
  3. Liquid or solid particles of less than 1 mm
  4. Solid particles in air

Answer. 3. Liquid or solid particles of less than 1 mm

Question 20. Ozone hole was first discovered by

  1. Robert Augus
  2. Molina
  3. Farman
  4. Rowland

Answer. 3. Farman

Question 21. Which is not an effect of acidic rain in a pond?

  1. Increased fungal growth.
  2. Decreased insect population.
  3. Increased growth of green algae.
  4. NO, and SO, saturation.

Answer. 3. Increased growth of green algae.

Question 22. The smog which is formed at high temperature is

  1. London smog
  2. Classical smog
  3. Los Angeles smog
  4. Sulfurous smog

Answer. 3. Los Angeles smog

Question 23. Brown air and gray air is due to the oxides of

  1. Sulfur
  2. Nitrogen
  3. Carbon
  4. Phosphorus

Answer. 2. Nitrogen

Question 24. Third pollution is

  1. Pollution caused by the addition of an undesirable substance in air, water, soil, or land
  2. Deterioration in the quality of air, water, soil, etc., due to removal or reduction in the quality of an important or vital ingredient
  3. Ground water pollution due to seepage of minerals, toxic chemicals, and sewage
  4. Landscape pollution caused by throwing of rubbish, wastes, and garbage over land

Answer. 4. Landscape pollution caused by throwing of rubbish, wastes, and garbage over land

Question 25. Which is not a control measure to reduce particulate matter in environment?

  1. Cyclonic separators
  2. Scrubbers
  3. Effluent treatment
  4. Electrostatic precipitator

Answer. 3. Effluent treatment

Question 26. A chemical weed in troposphere and protectant in stratosphere is

  1. CH4
  2. 0
  3. CFC
  4. NO2

Answer. 3. CFC

Question 27. Ganga Action Plan for controlling pollution in Ganges started in

  1. 1985
  2. 1981
  3. 1987
  4. 1989

Answer. 1. 1985

Question 28. The presence of 20 or more genera of algae in a water body is an indication of high organic pollution. It is

  1. Water index
  2. Algal diversity index
  3. Pollution index
  4. Algal genus index

Answer. 4. Algal genus index

Question 29. The presence of E. coli in water indicates

  1. Water is clear
  2. Water is fully polluted
  3. Inorganic pollution
  4. Fecal pollution

Answer. 4. Fecal pollution

Question 30. Blue-baby syndrome is due to

  1. Air pollution
  2. Soil pollution
  3. Thermal pollution
  4. Radioactive pollution

Answer. 2. Soil pollution

Question 31. The release of phosphates and nitrates in water bodies (i.e., in rivers and lakes) leads to

  1. Nutrient enrichment (eutrophication)
  2. Reduced algal growth
  3. Increased algal growth
  4. Increased growth of decomposers

Answer. 3. Increased algal growth

Question 32. Soil fertility is depleted due to

  1. Pan breaking
  2. Terracing
  3. Intensive agricultur
  4. Contour bunding

Answer. 3. Intensive agriculture

Question 33. Spraying of pesticide is an example of

  1. Point source water pollution
  2. Diffuse water pollution
  3. Both (1) and (2)
  4. Pyrolysis

Answer. 2. Diffuse water pollution

Question 34. Ecological backlash (or ecological boomerang) is

  1. Heat emission due to bomb explosion
  2. Production of useful ecological effect by a previously useful chemical
  3. Formation of secondary pollutant from the reaction of primary pollutants
  4. Production of adverse ecological effect by a previously useful chemical

Answer. 4. Production of adverse ecological effect by a previously useful chemical

Question 35. Minamata disease is due to

  1. Oil spill in water
  2. Arsenic in the atmosphere
  3. Industrial waste having mercury in water
  4. Organic waste in drinking water

Answer. 3. Industrial waste having mercury in water

Question 36. Oil slick causes mass-scale death of fishes due to

  1. Clogging of gills
  2. Disruption of food chain
  3. Non-availability of food
  4. All of these

Answer. 1. Clogging of gills

Question 37. Wastes may be sealed in concretefilled drums and discharged to a depth of about 500 m. This specific statement is true for

  1. Radiation pollutants
  2. UV radiation pollutants
  3. Particle pollutants
  4. All radioactive pollutants

Answer. 4. All radioactive pollutants

Question 38. Bone cancer is caused by

  1. Iodine 127
  2. Strontium 90
  3. Cesium 137
  4. None of these

Answer. 2. Strontium 90

Question 39. As a general rule, ionizing radiation is most damaging to

  1. Mature, stable cells
  2. Actively dividing cells
  3. Highly specialized cells
  4. Cells in which food is stored

Answer. 2. Actively dividing cells

Question 40. Volcanic eruptions let out large quantities of

  1. Harmful dust and sulfurous gases
  2. Harmful dust and nitrous gases
  3. Harmful dust and carbonous gases
  4. Harmful dust and phosphorous gases

Answer. 3. Harmful dust and carbonous gases

Question 41. Painful skeletal deformity called itai-itai is caused due to

  1. Cd
  2. Hg
  3. CO
  4. NO2

Answer. 1. Cd

Question 42. Acoustic zoning is related with

  1. Soil pollution
  2. Noise pollution
  3. Water pollution
  4. Air pollution

Answer. 2. Noise pollution

Question 43. Montreal Protocol was aimed to

  1. Reduce greenhouse gases
  2. Limit the production and use of ODS
  3. Mitigate climatic change
  4. Implement Agenda 21

Answer. 2. Limit the production and use of ODS

Question 44. The Government of India has introduced a concept to work closely with local communities for protection and management of forests called

  1. Jhum cultivation
  2. Chipko Movement
  3. Appiko Movement
  4. Joint Forest Management

Answer. 4. Joint Forest Management

Question 45. The National Forest Policy of India has recommended percent forest cover for hilly areas.

  1. 67
  2. 33
  3. 19.4
  4. 30

Answer. 1. 67

Question 46. To spread information and help on the practice of integrated organic farming is started by a group of farmers in

  1. Haryana
  2. Bangalore
  3. Delhi
  4. Jodhpur

Answer. 1. Haryana

Question 47. Find the odd one out with respect to e-waste:

  1. India
  2. Pakistan
  3. China
  4. America

Answer. 4. America

Question 48. Minerals, metals, and fossil fuels are which type of resources of energy?

  1. Renewable
  2. Non-renewable
  3. Biodegradable
  4. Degradable

Answer. 2. Non-renewable

Question 49. Thermal pollution is caused by

  1. Power plants
  2. Industries
  3. Automobiles
  4. All of the above

Answer. 4. All of the above

Question 50. The addition of any substance to water which leads to change in its physical and chemical characteristics is defined as water pollution. It results in

  1. Decreased turbidity
  2. Increased oxygenation
  3. Increased photosynthesis
  4. Increased turbidity and deoxygenation

Answer. 4. Increased turbidity and deoxygenation

Question 51. Which of the following is not a greenhouse gas?

  1. CH4
  2. N2O
  3. H2O
  4. CO2

Answer. 3. H2O

Question 52. High BOD indicates

  1. Highly polluted water
  2. Less pollution in H2O
  3. Less sewage
  4. Less microorganism

Answer. 1. Highly polluted water

Question 53. Increasing the concentration along food chain is of accumulated pollutant

  1. Biomagnification
  2. Bioaccumulation
  3. Eutrophication
  4. Biodiversity

Answer. 1. Biomagnification

Question 54. Which one of the following is a renewable source of energy?

  1. Petroleum
  2. Coal
  3. Nuclear fuel
  4. Trees

Answer. 4. Trees

Question 55. Spraying of DDT produces pollution of

  1. Air only
  2. Air and soil only
  3. Air, soil, and water
  4. Air and water only

Answer. 3. Air, soil, and water

Question 56. Sewage water is purified for recycling by the action of

  1. Light
  2. Microorganisms
  3. Aquatic plants
  4. Fishes

Answer. 2. Microorganisms

Question 57. Which one is not dangerous?

  1. Biopollutants
  2. Ozone layer
  3. Nuclear blast
  4. Deforestation

Answer. 2. Ozone layer

Question 58. Which of the following a set is greenhouse gases?

  1. CFC, CH4, CO2, N20
  2. CO2, CH4, N2, O2
  3. CO2, CH4, N2O3
  4. CO2, CFC, N2, O2

Answer. 1. CFC, CH4, CO2, N20

Question 59. Acid rain is due to pollution by

  1. CO2
  2. SO2 and NO2
  3. Dust particles
  4. Automobiles

Answer. 2. SO2 and NO2

Question 60. Which of the following is a biodegradable pollutant?

  1. Sewage
  2. Plastic
  3. Polythene
  4. DDT

Answer. 1. Sewage

Question 61. The most hazardous metal pollutant of automobile exhaust is

  1. Cadmium
  2. Lead
  3. Mercury
  4. Copper

Answer. 2. Lead

Question 62. Air quality indicator is

  1. Lichen
  2. Moss
  3. Algae
  4. None of these

Answer. 1. Lichen

Question 63. Blood hemoglobin has high affinity for

  1. CO2
  2. CO
  3. O2
  4. H2

Answer. 2. CO

Question 64. Minamata disease caused due to water pollution is due to

  1. Lead poisoning
  2. Arsenic chloride poisoning
  3. Mercury poisoning
  4. Ammonia pollution

Answer. 3. Mercury poisoning

Question 65. Effect of pollution is first marked on

  1. Microorganisms
  2. Green vegetation of an area
  3. Food crop
  4. None of these

Answer. 2. Green vegetation of an area

Question 66. Pollution is not caused by

  1. Thermal power plant
  2. Automobile
  3. Radioactive power plant
  4. Hydroelectric power plant

Answer. 4. Hydroelectric power plant

Question 67. Taj Mahal marble is affected by

  1. SO2
  2. O2
  3. O3
  4. NO2

Answer. 1. CO2

Question 68. Minamata disease first occurred in

  1. Japan
  2. China
  3. Korea
  4. Russia

Answer. 1. Japan

Question 69. Increase in the BOD of water reservoir is due to

  1. Algae
  2. Soil
  3. Moss
  4. Waste product

Answer. 4. Waste product

Question 70. Number of wildlife is continuously decreasing. What is the main reason behind this?

  1. Predation
  2. Cutting down of forest
  3. Destruction of habitat
  4. Hunting

Answer. 3. Destruction of habitat

Question 71. One of the following is associated with the conservation of forests. Find the one.

  1. Kaziranga
  2. Ghana
  3. Silent valley
  4. Gir

Answer. 3. Silent valley

Question 72. Which one of the following is a pair of endangered species?

  1. Garden lizard and Mexican poppy
  2. Rhesus monkey and sal tree
  3. Indian peacock and carrot grass
  4. Hornbill and Indian aconite

Answer. 4. Hornbill and Indian aconite

Question 73. If the Bengal Tiger becomes extinct,

  1. Hyenas and wolves will become scare
  2. The wild areas will be safe for man and domestic animals
  3. Its gene pool will be lost forever
  4. The populations of beautiful animals such as deers will get stabilized

Answer. 3. Its gene pool will be lost forever

Question 74. If high-altitude birds become rare or extinct, the plants which may disappear along with them are

  1. Pine
  2. Oak
  3. Orchids
  4. Rhododrons

Answer. 4. Rhododrons

Question 75. Which one of the following pairs of geographical areas shows maximum biodiversity in our country?

  1. Sunderbans and Rann of Kutch
  2. Eastern Ghats and West Bengal
  3. Eastern Himalaya and Western Ghats
  4. Kerala and Punjab

Answer. 3. Eastern Himalaya and Western Ghats

Question 76. One of the ex situ conservation methods for endangered species is

  1. Wildlife sanctuaries
  2. Biosphere reserves
  3. Cryopreservation
  4. National parks

Answer. 3. Cryopreservation

Question 77. Reason for the elimination of wildlife is

  1. Deforestation
  2. Forest fire
  3. Floods
  4. Less rainfall

Answer. 1. Deforestation

Question 78. The main reason of disturbance of biological diversity is

  1. Greenhouse effect
  2. Hunting
  3. Soil erosion
  4. Destruction of natural habitats

Answer. 4. Destruction of natural habitats

Question 79. The best method to preserve the wild relatives of plants is

  1. By growing them in natural habitats
  2. Gene library
  3. By storing seeds
  4. Cryopreservation

Answer. 1. By growing them in natural habitats

Question 80. Species diversity is the maximum in

  1. Tropical rain forest
  2. Temperate forest
  3. Deserts
  4. Hill slopes

Answer. 1. Tropical rain forest

Question 81. According to the Forestry Commission report 1997, the total forest cover of India was

  1. 11%
  2. 19.5%
  3. 17%
  4. 18.7%

Answer. 2. 19.5%

Question 82. What shall be the effect of destruction of wildlife?

  1. Wild gene of disease resistance will not be obtained
  2. Soil erosion
  3. Floods
  4. Greenhouse effect

Answer. 1. Wild gene of disease resistance will not be obtained

Question 83. The reason behind the occurrence of endemic species in South America and Australia is

  1. The species has been extinct from other regions
  2. Continental separation
  3. There is no terrestrial route to these places
  4. Retrogressive evolution

Answer. 2. Continental separation

Question 84. In your opinion, which is the most effective way to conserve the plant diversity of an area?

  1. By creating biosphere reserve
  2. By creating botanical garden
  3. By developing seed bank
  4. By tissue culture method

Answer. 1. By creating biosphere reserve

Question 85. The Biodiversity Act of India was passed by the Parliament in the year

  1. 2002
  2. 1992
  3. 1996
  4. 2000

Answer. 1. 2002

Question 86. According to the IUCN Red List, what is the status of red panda (Ailurus fulgens)?

  1. Critically species
  2. Vulnerable species
  3. Extinct species
  4. Endangered species

Answer. 4. Endangered species

Question 87. One of the most important functions of botanical gardens is that

  1. They provide a beautiful area for recreation
  2. One can observe tropical plants there
  3. They allow ex situ conservation of germplasm
  4. They provide the natural habitat for wildlife

Answer. 3. They allow ex situ conservation of germplasm

Question 88. Which of the following pairs of animal and plant represents endangered organisms in India?

  1. Cinchona and leopard
  2. Banyan and black buck
  3. Bentinckia nicobarica and red panda
  4. Tamarind and rhesus monkey

Answer. 3. Bentinckia nicobarica and red panda

Question 89. Which one of the following is not included under in situ conservation?

  1. Biosphere reserve
  2. National park
  3. Sanctuary
  4. Botanical garden

Answer. 4. Botanical garden

Question 90. Which one of the following is the correctly matched pair of endangered animal and national park?

  1. Wild ass-Dudhwa National Park
  2. Great Indian-Keoladeo National Park Bustard
  3. Lion-Corbett National Park
  4. Rhinoceros-Kaziranga National Park

Answer. 4. Rhinoceros-Kaziranga National Park

Question 91. Which of the following is considered a hot-spot of biodiversity in India?

  1. Eastern Ghats
  2. Aravalli Hills
  3. Western Ghats
  4. Indo-Gangetic Plain

Answer. 3. Western Ghats

Question 92. Identify the odd combination of the habitat and the particular animal concerned:

  1. Rann of Kutch-Wild ass
  2. Dachigam National Park-Snow leopard
  3. Sunderbans-Bengal tiger
  4. Periyar-Elephant

Answer. 2. Dachigam National Park-Snow leopard

Question 93. Which one of the following pairs of organisms are exotic species introduced in India?

  1. Nile perch, Ficus religiosa
  2. Ficus religiosa, Lantana camara
  3. Lantana camara, Water hyacinth
  4. Water hyacinth, Prosopis cinereia

Answer. 3. Lantana camara, Water hyacinth

Question 94. Which one of the following is not observed in biodiversity hotspots?

  1. Lesser inter-specific competition
  2. Species richness
  3. Endemism
  4. Accelerated species loss

Answer. 1. Lesser inter-specific competition

Question 95. Tiger is not a resident in which one of the following national parks?

  1. Jim Corbett
  2. Ranthambhor
  3. Sunderbans
  4. Gir

Answer. 4. Gir

Question 96. Which one of the following is an example of ex situ conservation?

  1. Wildlife sanctuary
  2. Seed bank
  3. Sacred groves
  4. National park

Answer. 2. Seed bank

Question 97. The Indian Rhinoceros are a natural inhabitant of which Indian state?

  1. Uttar Pradesh
  2. Himachal Pradesh
  3. Assam
  4. Uttarakhand

Answer. 3. Assam

Question 98. Which of the following is the non-conventional source of energy?

  1. Coal
  2. Petroleum
  3. Electricity from nuclear power plants
  4. Solar radiations

Answer. 4. Solar radiations

Question 99. Petroleum resource is

  1. Renewable
  2. Non-renewable
  3. Synthetic and biodegradable
  4. Infinite and unconventional,

Answer. 2. Non-renewable

Question 100. Biological oxygen demand (BOD) is a measure of

  1. Industrial wastes poured into water bodies
  2. Extent to which water is polluted with organic compounds
  3. Amount of carbon monoxide inseparably combined with hemoglobin
  4. Amount of oxygen needed by green plants during night

Answer. 2. Extent to which water is polluted with organic compounds

Question 101. In almost all Indian metropolitan cities such as Delhi, the major atmospheric pollutant/s is/are

  1. Suspended particulate matter (SPM)
  2. Oxides of sulfur
  3. Carbon dioxide and carbon monoxide
  4. Oxides of nitrogen

Answer. 1. Suspended particulate matter (SPM)

Question 102. Nitrogen oxides produced from the emission of automobiles and power plants are the source of fine air borne particles which lead to

  1. Photochemical smog
  2. Dry acid deposition
  3. Industrial smog
  4. Wet acid deposition

Answer. 2. Dry acid deposition

Question 103. A lake with an inflow of domestic sewage rich in organic waste may result in

  1. Drying of the lake very soon due to algal bloom
  2. An increased production of fish due to lots of nutrients
  3. Death of fish due to lack of oxygen
  4. Increased population of aquatic food web organisms

Answer. 3. Death of fish due to lack of oxygen

Question 104. Minamata disease was caused due to the consumption of

  1. Sea food containing a lot of cadmium
  2. Fish contaminated with mercury
  3. Oysters with a lot of pesticide
  4. Sea food contaminated with selenium

Answer. 2. Fish contaminated with mercury

Question 105. Which one of the following statements pertaining to pollutants is correct?

  1. DDT is a non-biodegradable pollutant.
  2. Excess fluoride in drinking water causes osteoporosis.
  3. Excess cadmium in drinking water causes black foot disease.
  4. Methyl mercury in water may cause “itai itai” disease.

Answer. 1. DDT is a non-biodegradable pollutant.

Question 106. If CO2 is absent in the atmosphere of earth, then

  1. Temperature will decrease
  2. Temperature will increase.
  3. Plants will flourish well
  4. No effect

Answer. 1. Temperature will decrease

Question 107. CO is harmful because

  1. It forms stable compound with hemoglobin
  2. It blocks mitosis
  3. It is mutagenic
  4. It causes defloation

Answer. 1. It forms stable compound with hemoglobin

Question 108. Besides CH, and CO2, other greenhouse gas from agriculture area is

  1. SO2
  2. NH3
  3. NO2
  4. CFC

Answer. 3. NO2

Question 109. Temperature variation in Pacific Ocean in present time is called

  1. Cyclone effect
  2. El Niño effect
  3. Greenhouse effect
  4. Gaudikov’s effect

Answer. 2. El Niño effect

Question 110. Sewage purification is performed by

  1. Microbes
  2. Fertilizers
  3. Antibiotics
  4. Antiseptics

Answer. 1. Microbes

Question 111. The best economic method to harvest the solar energy is

  1. Solar cell
  2. Energy plantation
  3. Cultivation of sugarcane; then energy obtained by burning it
  4. Solar cooker

Answer. 2. Energy plantation

Question 112. The Bhopal Gas Tragedy is related with

  1. Methane
  2. Carbon monoxide
  3. Methyl isocyanate (MIC)
  4. SO2

Answer. 3. Methyl isocyanate (MIC)

Question 113. The concentration of DDT is the highest in

  1. Primary consumer
  2. Producers
  3. Top consumer
  4. Decomposers

Answer. 3. Top consumer

Question 114. Lichens can be used

  1. Bioindicator for water and air pollution
  2. Initial vegetation for waste lands
  3. Source of wood
  4. To check air pollution

Answer. 1. Bioindicator for water and air pollution

Question 115. What is phytotron?

  1. A device to grow plants in controlled environment.
  2. Growing plants in greenhouse.
  3. Radiation chamber to induce mutations.
  4. Apparatus to study the effect of light on plants.

Answer. 1. A device to grow plants in controlled environment.

Question 116. Which of the following is a secondary pollutant?

  1. PAN
  2. CO
  3. NO2
  4. SO2

Answer. 1. PAN

Question 117. Maximum DDT is present in birds feeding on

  1. Fishes
  2. Meat
  3. Insects
  4. Seeds

Answer. 1. Fishes

Question 118. Which one is associated with occupational hazard?

  1. Fluorosis
  2. Pneumoconiosis
  3. Silicosis
  4. Asthama

Answer. 2. Pneumoconiosis

Question 119. Greenhouse effect is

  1. Gardening outside the house
  2. Global cooling
  3. Global warming
  4. Green color house

Answer. 3. Global warming

Question 120. What is BOD?

  1. The amount of O2 utilized by organisms in water.
  2. The amount of O2 utilized by microorganisms for decomposition.
  3. The total amount of O2 present in water.
  4. All of the above.

Answer. 2. The amount of O2 utilized by microorganisms for decomposition.

Question 121. What is the intensity of sound in normal conversation?

  1. 10-20 db
  2. 30-60 db
  3. 70-90 db
  4. 120-150 db

Answer. 2. 30-60 db

Question 122. Which of the following is absent in polluted water?

  1. Hydrilla
  2. Water hyacinth
  3. Larva of stone fly
  4. Blue green algae

Answer. 3. Larva of stone fly

Question 123. The maximum greenhouse gas is released by which country?

  1. India
  2. France
  3. USA
  4. Britain

Answer. 3. USA

Question 124. Lead concentration in blood is considered alarming if it is

  1. 30 mg/100 ml
  2. 4-6 mg/100 ml
  3. 10 mg/100 ml
  4. 20 mg/100ml

Answer. 3. 10 mg/100 ml

Question 125. In 1984, the Bhopal Gas Tragedy took place because methyl isocyanate

  1. Reacted with ammonia.
  2. Reacted with CO2
  3. Reacted with water
  4. Reacted with DDT

Answer. 3. Reacted with water

Question 126. Blood analysis of a patient reveals an unusually high quantity of carboxyhemoglobin content. Which of the following conclusion is the most likely to be correct? The patient has been inhaling polluted air containing unusually high content of

  1. Carbon monoxide
  2. Carbon disulfide
  3. Chloroform
  4. Carbon dioxide

Answer. 1. Carbon monoxide

Question 127. The common indicator organism of water pollution is

  1. Entamoeba histolytica
  2. Lemna paucicostata
  3. Eichhornia crassipes
  4. Escherichia coli

Answer. 4. Escherichia coli

Question 128. Which one of the following pairs in mismatched?

  1. Nuclear power – Radioactive wastes
  2. Solar energy – Greenhouse effect
  3. Fossil fuel burning – Release of CO2
  4. Biomass burning-Release of CO2

Answer. 2. Solar energy – Greenhouse effect

Question 129. Identify the correctly matched pair?

  1. Kyoto Protocol-Climatic change
  2. Montreal Protocol – Global warming
  3. Basal convention Biodiversity conservation
  4. Ramsar convention-Ground water pollution

Answer. 1. Kyoto Protocol-Climatic change

Question 130. Prolonged liberal irrigation of agricultural fields is likely to create the problem of

  1. Acidity
  2. Aridity
  3. Salinity
  4. Metal toxicity

Answer. 3. Salinity

Question 131. Which of the following is not used for the disinfection of drinking water?

  1. Chlorine
  2. Ozone
  3. Chloramine
  4. Phenyl

Answer. 4. Phenyl

Question 132. The limit of BOD prescribed by the Central Pollution Control Board for the discharge of industrial and municipal waste waters into natural surface waters is 

  1. < 100 ppm
  2. <30 ppm
  3. <3 ppm
  4. < 10 ppm

Answer. 2. <30 ppm

Question 133. The “blue baby” syndrome results from

  1. Excess of dissolved oxygen
  2. Excess of TDS (total dissolved solids)
  3. Excess of chloride
  4. Methaemoglobinaemia

Answer. 4. Methaemoglobinaemia

Question 134. Montreal Protocol, which calls for appropriate action to protect the ozone layer from human activities, was passed in the year

  1. 1988
  2. 1985
  3. 1986
  4. 1987

Answer. 4. 1987

Question 135. Photochemical smog pollution does not contain

  1. Carbon dioxide
  2. PAN (peroxy acyl nitrate)
  3. Ozone
  4. Nitrogen dioxide

Answer. 1. Carbon dioxide

Question 136. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of pollution?

  1. CO
  2. SO2
  3. NO
  4. SPM

Answer. 4. SPM

Question 137. Which one of the following is not a bioindicator of water

  1. Sewage fungus
  2. Sludge worms
  3. Blood-worms
  4. Stone flies

Answer. 4. Stone flies

Question 138. Which one of the following is the correct percentage of the two (out of the total of four) greenhouse gases that contribute to the total global warming?

  1. N,O 6%, CO, 86%
  2. Methane 20%, N2O 18%
  3. CFCs 14%, methane 20%
  4. CO2 40%, CFCs 30%

Answer. 3. CFCs 14%, methane 20%

Question 139. The World Summit on Sustainable Development (2002) was held in

  1. Argentina
  2. South Africa
  3. Brazil
  4. Sweden

Answer. 2. South Africa

Question 140. About 70% of total global carbon is found in

  1. Ocean
  2. Forests
  3. Desert
  4. Rain forest

Answer. 1. Ocean

Question 141. A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this?

a. Lots of urea and phosphate fertilizers were used in the crops in the vicinity.

b. The area was sprayed with DDT by an aircraft.

c. The lake water turned green and stinky.

d. Phytoplankton population in the lake declined initially thereby greatly reducing photosynthesis.

Which two of the above were the main causes of fish mortality in the lake?

  1. (a), (c)
  2. (a), (b)
  3. (b), (c)
  4. (c), (d)

Answer. 1. (a), (c)

Question 142. According to the Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometers) of the air pollutants is responsible for the greatest harm to human health?

  1. 1.0 or less
  2. 5.2-2.5
  3. 2.5 or less
  4. 1.5 or less

Answer. 3. 2.5 or less

Question 143. The Montreal Protocol aims at

  1. Control of CO2 emission
  2. Reduction of ozone depleting substances
  3. Biodiversity conservation
  4. Control of water pollution

Answer. 2. Reduction of ozone depleting substances

Question 144. The Chipko Movement was launched for the protection of

  1. Wet lands
  2. Grasslands
  3. Forests
  4. Livestock

Answer. 3. Forests

Question 145. Steps taken by the Government of India to control air pollution include

  1. Use of non-polluting compressed natural gas (CNG) only as fuel by all buses and trucks
  2. Compulsory mixing of 20% ethyl alcohol with petrol and 20% biodiesel with diesel
  3. Compulsory PUC (pollution under control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons
  4. Permission to use only pure diesel with a maximum of 500 ppm sulfur as fuel for vehicles

Answer. 1. Use of non-polluting compressed natural gas (CNG) only as fuel by all buses and trucks

Question 146. Biochemical oxygen demand (BOD) in river water

  1. Increases when sewage gets mixed with river water
  2. Remains unchanged when algal bloom occurs
  3. Has no relationship with the concentration of oxygen in water
  4. Gives a measure of Salmonella in water

Answer. 1. Increases when sewage gets mixed with river water

Question 147. DDT residues are rapidly passed through food chain causing biomagnification because DDT is

  1. Water soluble
  2. Fat soluble
  3. Moderately toxic

Non-toxic to aquatic animals

Answer. 2. Fat soluble

Question 148. Global agreement in specific control strategies to reduce the release of ozone depleting substances was adopted by 

  1. The Vienna Convention
  2. Rio de Janeiro Conference
  3. The Montreal Protocol
  4. The Koyoto Protocol

Answer. 3. The Montreal Protocol

Question 149. Breeding of crops with high levels of minerals, vitamins, and proteins is called

  1. Somatic hybridization
  2. Biofortification
  3. Biomagnification
  4. Micropropagation

Answer. 2. Biofortification

Question 150. The two gases making the highest relative contribution to the greenhouse gases are

  1. CO2 and CH4
  2. CH, and N2O
  3. CFCs and N2O
  4. CO2 and N2O

Answer. 1. CO2 and CH4

Question 151. A renewable exhaustible natural resource is

  1. Coal
  2. Petroleum
  3. Minerals
  4. Forest.

Answer. 4. Forest.

Question 152. When domestic sewage mixes with river water,

  1. The increased microbial activity releases micronutrients such as iron
  2. The increased microbial activity uses up dissolved oxygen
  3. The river water is still suitable for drinking as impurities are only about 0.1%
  4. Small animals such as rats will die after drinking river water

Answer. 2. The increased microbial activity uses up dissolved oxygen

Question 153. Measuring BOD is a method used for

  1. Working out the efficiency of oil driven automobile engines.
  2. Measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale
  3. Working out the efficiency of RBCs about their capacity to carry oxygen
  4. Estimating the amount of organic matter in sewage water

Answer. 4. Estimating the amount of organic matter in sewage water

Question 154. Which one of the following is a wrong statement?

  1. Ozone in the upper part of atmosphere is harmful to animals.
  2. Greenhouse effect is a natural phenomenon.
  3. Eutrophication is a natural phenomenon in fresh water bodies.
  4. Most of the forests have been lost in tropical areas.

Answer. 1. Ozone in the upper part of atmosphere is harmful to animals.

Question 155. Which one of the following areas in India is a hotspot of biodiversity?

  1. Gangetic Plain
  2. Sunderbans
  3. Western Ghats
  4. Eastern Ghats

Answer. 3. Western Ghats

Question 156. Select the correct statement about biodiversity:

  1. The desert areas of Rajasthan and Gujarat have a very high level of desert animal species as well as numerous rare animals.
  2. Large scale planting of Bt cotton has no adverse effect on biodiversity.
  3. Western Ghats have a very high degree of species richness and endemism.
  4. Conservation of biodiversity is just a fad pursued by the developed countries.

Answer. 3. Western Ghats have a very high degree of species richness and endemism.

NEET Biology Multiple Choice Questions – Biodiversity And Conservation

Biodiversity And Conservation Multiple Choice Questions

Question 1. Out of more than 1.5 million known species, insects are of the total animals.

  1. 70%
  2. 25%
  3. 50%
  4. 75%

Answer. 1. 70%

Question 2. Which is not true regarding genetic diversity?

  1. It enables a population to adapt to its environment.
  2. It is also the basis of speciation.
  3. Ecotype formation depends upon it.
  4. Higher diversity increases uniformity.

Answer. 4. Higher diversity increases uniformity.

Question 3. Regional diversity is also called

  1. Alpha diversity
  2. Beta diversity
  3. Gamma diversity
  4. Ecosystem diversity

Answer. 3. Gamma diversity

Question 4. Which of the following biogeographical regions in India has the highest coverage?

  1. Deccan Peninsula
  2. NE Himalayas
  3. Western Ghats
  4. Gangetic Plain

Answer. 1. Deccan Peninsula

Question 5. Which is not a reason of maximum diversity in tropics?

  1. Higher pest pressure
  2. Evolutionary older zone
  3. High rate of out-crossing
  4. Greater environmental variations

Answer. 4. Greater environmental variations

Question 6. Threats to biodiversity come from

  1. Habitat loss
  2. Over exploitation
  3. Intensive agriculture
  4. All of the above

Answer. 4. All of the above

Question 7. The disappearance of cheetah from India and its existence in other part of the world is an example of

  1. Extinction
  2. Extirpation
  3. Background extinction
  4. Anthropogenic extinction

Answer. 2. Extirpation

Question 8. Silent Valley of Kerala is being preserved because it has

  1. Rare plants and animals
  2. Only natural forest of India
  3. Costly timber plants
  4. Recreational value

Answer. 1. Rare plants and animals

Question 9. Anti-forest conservation is

  1. Selective felling
  2. Control of forest fire
  3. Large-scale clearing
  4. Ban on hunting

Answer. 1. Selective felling

Question 10. The species which are likely to be in the danger of extinction in the near future if the factors threatening their extinction continue are known as

  1. Threatened species
  2. Rare species
  3. Vulnerable species
  4. Endangered species

Answer. 3. Vulnerable species

Question 11. In India, forests constitute about

  1. 19.4% of the land area
  2. 33.7% of the land area
  3. 33% of the land area
  4. 67% of the land area

Answer. 1. 19.4% of the land area

Question 12. Bamboos are abundant in

  1. Dry moist deciduous tropical forests
  2. Coniferous forests
  3. Alpine forests
  4. Rain forests

Answer. 1. Dry moist deciduous tropical forests

Question 13. 85% of world’s food comes from

  1. < 20 plant species
  2. < 50 plant species
  3. < 5 plant species
  4. < 100 plant species

Answer. 1. < 20 plant species

Question 14. A population characteristic of a species susceptible to extinction is

  1. Low trophic level in food chain
  2. Inability to switch over to alternate food source
  3. Wide range of distribution
  4. High biotic potential

Answer. 2. Inability to switch over to alternate food source

Question 15. The number of red list categories prepared by WCU (IUCN) is

  1. 6
  2. 7
  3. 8
  4. 9

Answer. 3. 8

Question 16. According to IUCN, when a taxon is facing an extremely high risk of extinction in the immediate future, it is

  1. Extinct in the wild
  2. Endangered
  3. Critically endangered
  4. Vulnerable

Answer. 3. Critically endangered

Question 17. Projected areas are examples of

  1. In situ conservation
  2. Ex situ conservation
  3. Cryopreservation
  4. Green houses

Answer. 1. In situ conservation

Question 18. The zone of biosphere reserve where no human activity is permitted is known as

  1. Buffer zone
  2. Core zone
  3. Manipulation zone
  4. None of these

Answer. 2. Core zone

Question 19. Floods can be prevented by

  1. Making the soil less sloppy
  2. Removing forests
  3. Removing soil cover
  4. Planting trees on slopes and building dams

Answer. 4. Planting trees on slopes and building dams

Question 20. Indian rhinoceros is the most important protected species in

  1. Gir National Park
  2. Bandipur National Park
  3. Corbett National Park
  4. Kaziranga National Park

Answer. 4. Kaziranga National Park

Question 21. The Government of India has provided private ownership rights in

  1. A national park
  2. A sanctuary
  3. A biosphere reserve
  4. Zoo

Answer. 2. A sanctuary

Question 22. Wild populations of plants and animals and traditional life styles of tribals are protected in

  1. Biosphere reserve
  2. Sanctuary
  3. National park
  4. None of these

Answer. 1. Biosphere reserve

Question 23. Man-made mass extinction of species represents a severe depletion of biodiversity called

  1. Mass extinction
  2. Natural extinction
  3. Anthropogenic extinction
  4. Human extinction

Answer. 3. Anthropogenic extinction

Question 24. Which of the following exotic species has become menace to many water bodies in India?

  1. Lantana camara
  2. Eichhomia crassipes
  3. Parthenium hysterophorus
  4. Eupatorium odoratum

Answer. 2. Eichhomia crassipes

Question 25. Which is not a criterion used for determining hot spots?

  1. Number of endemic species
  2. Degree of habitat destruction
  3. Haying traditional strategy for protection of biodiversity
  4. Degree of exploitation

Answer. 3. Haying traditional strategy for protection of biodiversity

Question 26. Which anticancerous botano-chemical is obtained from a gymnosperm?

  1. Ephedrine
  2. Strychnine
  3. Taxol
  4. Reserpine

Answer. 3. Taxol

Question 27. Which potato species is nematode resistant?

  1. Solanum spegazzini
  2. S. demissum
  3. S. acaule
  4. S. stoloniferum

Answer. 1. Solanum spegazzini

Question 28. A few years ago, the brown plant hopper (Nilaparvata lunges) threatened the cultivation of

  1. Wheat
  2. Rice
  3. Maize
  4. Millets

Answer. 2. Rice

Question 29. An important international effort or convention for biodiversity conservation is

  1. UNESCO
  2. WWF
  3. IBWL
  4. NBPGR

Answer. 2. WWF

Question 30. Find the odd one out (with respect to weed):

  1. Lantana camara
  2. Eicchornia
  3. Parthenium argentatum
  4. Parthenium hysterophorus

Answer. 3. Parthenium argentatum

Question 31. How many species became extinct in the last 500 years?

  1. 338
  2. 359
  3. 784
  4. 2000

Answer. 3. 784

Question 32. How many hot spots cover India’s high biodiversity regions?

  1. 25
  2. 3
  3. 34
  4. 2

Answer. 2. 3

Question 33. Overexploitation has resulted in the extinction of

  1. Steller’s cow
  2. Lantana
  3. Passenger pigeon
  4. Both (1) and (3)

Answer. 4. Both (1) and (3)

Question 34. Wildlife (protection) Act 1972 includes which of the following objectives?

  1. Setting up and managing sanctuaries and national parks
  2. Restriction and prohibition on hunting animals
  3. Protection of specified plants
  4. All of the above

Answer. 4. All of the above

Question 35. Best way to preserve the wildlife is

  1. To kill the predators
  2. Vaccinize the animals
  3. Optimize the breeding habit
  4. To preserve their natural habitat

Answer. 4. To preserve their natural habitat

Question 36. Wildlife conservation aims at

  1. Maintaining the ecological process
  2. Enriching the wildlife diversity with exotic species
  3. Preventing migration of species
  4. Maintaining the diversity of life

The correct statements are:

  1. (1), (4)
  2. (3), (4)
  3. (1), (2)
  4. (2), (3)

Answer. 1. (1), (4)

Question 37. All forms of life should be conserved because

  1. They will be otherwise lost
  2. They have economic values
  3. They maintain diverse genetic resources
  4. They are important for maintaining balance of nature

Answer. 3. They maintain diverse genetic resources

Question 38. Which of the following types of animals does man chiefly protect?

  1. Week animals
  2. Harmless animals
  3. Those likely to perish
  4. Economically useful animals

Answer. 3. Those likely to perish

Question 39. The national bird of India is

  1. Peacock
  2. The hornbill
  3. Black swan
  4. House sparrow

Answer. 1. Peacock

Question 40. Scientific name of our national bird is

  1. Gallus gallus
  2. Columba livia
  3. Pava cristatus
  4. Corvus splendens

Answer. 3. Pava cristatus

Question 41. The biological name of the domestic cat is

  1. Felis leo
  2. Panthera indica
  3. Panthera domestica
  4. Felis domestica

Answer. 4. Felis domestica

Question 42. The “Sangai” of Manipur is a

  1. Great pied hornbill
  2. Black-necked crane
  3. Brow antlered deer
  4. Retienlated python

Answer. 3. Brow antlered deer

Question 43. Sarus is also known as

  1. Crane
  2. Spotbill
  3. Plovers
  4. Flamingoes

Answer. 1. Crane

Question 44. Black buck is

  1. Cervulus muntiac
  2. Antilope cervicapra
  3. Moschus moschiferus
  4. Boselaphus trogocamelus

Answer. 2. Antilope cervicapra

Question 45. Which among the following is an Indian monkey?

  1. Simia
  2. Gorilla
  3. Macaca
  4. Pongidae
  5. Ramapithecus

Answer. 3. Macaca

Question 46. Number of wildlife is continuously decreasing. What is the main reason for this?

  1. Hunting
  2. Predation
  3. Cutting down forest
  4. Destruction of habitat

Answer. 4. Destruction of habitat

Question 47. Most of the endangered species are victims of

  1. Acid rain
  2. Over-hunting
  3. Habitat destruction
  4. Competition with introduced species

Answer. 3. Habitat destruction

Question 48. The main reason for extinction of species is

  1. Hunting
  2. Destruction of habitat
  3. Pollution
  4. None of these

Answer. 2. Destruction of habitat

Question 49. Wildlife is destroyed most when

  1. Mass scale hunting for foreigan trade
  2. Natural habitat is destroyed
  3. There is lack of proper care
  4. There is natural calamity

Answer. 2. Natural habitat is destroyed

Question 50. Wildlife is conserved in

  1. In situ
  2. Ex situ
  3. Both (1) and (2)
  4. None of these

Answer. 3. Both (1) and (2)

Question 51. Establishment of national parks and sanctuaries is a strategy for

  1. Conservation of wildlife
  2. Studying wildlife biology
  3. Creating awareness about wildlife
  4. Preventing wild animals entering villages

Answer. 1. Conservation of wildlife

Question 52. India now has

  1. 10 biosphere reserves, 50 national parks, and 400 wildlife sanctuaries
  2. 14 biosphere reserves, 50 national parks, and 400 wildlife sanctuaries
  3. 10 biosphere reserves, 90 national parks, and 448 wildlife sanctuaries
  4. 10 biosphere reserves, 96 national parks, and 441 wildlife sanctuaries

Answer. 4. 10 biosphere reserves, 96 national parks, and 441 wildlife sanctuaries

Question 53. An example for in situ biological conservation method is to establish

  1. Zoos
  2. Seed banks
  3. Botanical gardens
  4. Biosphere reserves

Answer. 4. Biosphere reserves

Question 54. Dachigam National Park in Srinagar is associated with the animal

  1. Hangul
  2. Rhino
  3. Musk deer
  4. Nilgiri tahr

Answer. 1. Hangul

Question 55. Dachigam sanctuary is located in

  1. WB
  2. MP
  3. J&K
  4. Rajasthan

Answer. 3. J&K

Question 56. Identify the odd combination of the habitat and the particular animal concerned:

  1. Periyar – Elephant
  2. Rann of Kutch – Wild ass
  3. Sunderbans – Bengal tiger
  4. Dachigam National Park – Snow leopard

Answer. 4. Dachigam National Park – Snow leopard

Question 57. National animal of India is

  1. Lion
  2. Tiger
  3. Antelope
  4. Elephant

Answer. 2. Tiger

Question 58. “Project Tiger” in India was launched in the year

  1. 1973
  2. 1981
  3. 1985
  4. 1988

Answer. 1. 1973

Question 59. “Project Tiger” in India was launched following the recommendation of

  1. IBWL
  2. BNHS
  3. CITES
  4. NWAP

Answer. 1. IBWL

Question 60. Identify the correct match between tiger reserve and its state?

  1. Palamu – Odisha
  2. Manas – Assam
  3. Bandipur – Tamil Nadu
  4. Corbett – Madhya Pradesh

Answer. 2. Manas – Assam

Question 61. Bandipur National Park is associated with

  1. Tiger
  2. Deer
  3. Elephant
  4. Rhinoceros

Answer. 1. Tiger

Question 62. Bandipur in Karnataka is the site of

  1. Project Tiger
  2. Project Hangul
  3. Project Peacock
  4. Project Elephant

Answer. 1. Project Tiger

Question 63. Which of the following is the smallest tiger reserve?

  1. Simlipal
  2. Palamau
  3. Namdapha
  4. Ranthambore

Answer. 4. Ranthambore

Question 64. The Ranthambore National Park is located in

  1. Gujarat
  2. Rajasthan
  3. Uttar Pradesh
  4. Maharashtra

Answer. 2. Rajasthan

Question 65. Kanha National Park is famous for

  1. Birds
  2. Tigers
  3. Crocodiles
  4. Rhinoceros

Answer. 2. Tigers

Question 66. Recently attempts are being made to reintroduce tigers in this famous National Park:

  1. Sarika
  2. Kanha
  3. Corbett
  4. Bandavgarh

Answer. 1. Sarika

Question 67. Sarika Tiger Reserve is located in

  1. Odisha
  2. Assam
  3. Rajasthan
  4. West Bengal

Answer. 3. Rajasthan

Question 68. Royal Bengal Tiger is conserved in

  1. Gir forest
  2. Sunderbans
  3. Kanha National Park
  4. Jim Corbett National Park

Answer. 2. Sunderbans

Question 69. The largest number of tigers is reported from

  1. Manas
  2. kanha
  3. Simlipal
  4. Sunderbans

Answer. 4. Sunderbans

Question 70. All Sunderban tigers are

  1. Man-eaters
  2. Good swimmers
  3. Eaters of fish and crabs
  4. All of the above

Answer. 4. All of the above

Question 71. The first white tiger in the world was found in

  1. Gir in Saurashtra
  2. Sunderbans in Bengal
  3. Rewa in Madhya Pradesh
  4. Jim Corbett National Park in Uttarakhand

Answer. 2. Sunderbans in Bengal

Question 72. Which is correct about white tiger?

  1. It is a type of albino.
  2. It is a recessive mutant.
  3. It is a transgenic animal.
  4. It is a part of subspecies of Indian tiger.

Answer. 2. It is a recessive mutant.

Question 73. If the Bengal Tiger becomes extinct,

  1. Its gene pool will be lost for ever
  2. Hyenas and wolves will become scarce
  3. The wild areas will be safe for man and domestic animals
  4. The populations of beautiful animals like deers will get stabilized

Answer. 1. Its gene pool will be lost for ever

Question 74. Sacred groves are found in

  1. Bihar
  2. Punjab
  3. Meghalaya
  4. Jammu and Kashmir

Answer. 3. Meghalaya

Question 75. Conservation of organism in natural habitat is called

  1. Ex situ conservation
  2. In situ conservation
  3. Both (1) and (2)
  4. None of the above

Answer. 2. In situ conservation

Question 76. In situ conservation of natural genetic resources can be achieved by establishing

  1. National Parks
  2. Wildlife sanctuaries
  3. Biosphere reserves
  4. All of these

Answer. 4. All of these

Question 77. What is common to the techniques (1) in vitro fertilization, (2) cryopreservation, and (3) tissue culture?

  1. All are in situ conservation methods.
  2. All are ex situ conservation methods.
  3. All require ultra modern equipment and large space.
  4. All are methods of conservation of extinct organisms.Answer. 2. All are ex situ conservation methods.

Question 78. BNHS is the abbreviated form for

  1. Border Natural History Society
  2. Bombay National History Society
  3. Border National History Services
  4. Bombay Natural History Societes

Answer. 4. Bombay Natural History Societes

Question 79. The emblem of Bombay Natural History Society (BNHS) is given. Identify the bird.

NEET Biology Biodiversity And Conservation Question 46

  1. Eagle
  2. Erget
  3. Kingfisher
  4. Hornbill

Answer. 4. Hornbill

Question 80. Which one of the following bird is endangered?

  1. Kite
  2. Parrot
  3. Hornbill
  4. Pigeon

Answer. 3. Hornbill

Question 81. The World Animal Welfare Day is celebrated on

  1. March 21
  2. June 5
  3. October 3
  4. October 4

Answer. 4. October 4

Question 82. 21st March is

  1. World Forest Day
  2. World Animal Day
  3. World Environment Day
  4. World Habitat Day

Answer. 1. World Forest Day

Question 83. The world biodiversity day is celebrated annually on

  1. 5th June
  2. 22nd April
  3. 29th December
  4. 16th September

Answer. 3. 29th December

Question 84. World Wildlife Week is celebrated on

  1. June 15-22
  2. March 1-7
  3. October 1-7
  4. June 1-7

Answer. 3. October 1-7

Question 85. Who have recently tried to put price tags on nature’s life support services?

  1. Nile Perch and his colleagues
  2. Herbert Boyer and his colleagues
  3. Ramdeo Misra and his colleagues
  4. Robert Costanza and his colleagues

Answer. 4. Robert Costanza and his colleagues

Question 86. Match Column 1 with Column 2 and select the correct answer using the codes given.

Column 1                                   Column 2

A. World Habitat Day              1. December 3

B. World Environment Day     2. October 3

C. World Conservation Day    3. March 21

D. World Forestry Day            4. June 5

  1. A = 4, B = 1, C = 3, D = 2
  2. A = 2, B = 4, C = 1, D = 3
  3. A = 2, B = 1, C=4, D=3
  4. A = 3, B = 4, C=2, D=1

Answer. 2. A = 2, B = 4, C = 1, D = 3

Question 87. Choose the wrongly matched pair:

  1. Carrot grass – Lantana
  2. Wildlife safari parks – Ex situ conservation
  3. Amazon rain forest – Lungs of the planet
  4. Khasi and Jaintia Hills – Meghalaya
  5. World Summit on Sustainable – Johannesburg Development, 2002

Answer. 1. Carrot grass – Lantana

Question 88. The relation between species richness and area is described on a logarithmic scale by the equation [where S is species richness, A is area, Z is the slope of the line (regression coefficient), C is the Y-intercept].

  1. log S = log C
  2. log S = Z log A
  3. log S = log C-Z log A
  4. log S = log C+ Z log A
  5. log C = log S+ Z log A

Answer. 4. log S = log C+ Z log A

Question 89. Sacred groves are specially useful in

  1. Preventing soil erosion
  2. Year round flow of water in river
  3. Generating environment awareness
  4. Conserving rare and threatened species

Answer. 4. Conserving rare and threatened species

Question 90. Select the correct statement about biodiversity:

  1. The desert areas of Rajasthan and Gujarat have a very high level of desert animal species as well as numerous rare animals.
  2. Large scale planting of Bt-cotton has no adverse effect on biodiversity.
  3. Western Ghats have a very high degree of species richness and endemism.
  4. Conservation of biodiversity is just a fad pursued by the developed countries.

Answer. 3. Western Ghats have a very high degree of species richness and endemism.

Question 91. Which of the following plants are commonly found in Sunderban Biosphere Reserve?

  1. Cactus
  2. Conifers
  3. Juniperus
  4. Mangroves

Answer. 4. Mangroves

Question 92. All the following are included under in situ conservation except

  1. National park
  2. Sanctuary
  3. Botanical garden
  4. Biosphere reserve

Answer. 3. Botanical garden

Question 93. Slash and burn agriculture is the other name of

  1. Step farming
  2. Crop rotation
  3. Organic garden
  4. Jhum cultivation

Answer. 4. Jhum cultivation

Question 94. Which one of the following is not a wildlife conservation project?

  1. Project Dodo
  2. Project Tiger
  3. Project Hangul
  4. Project Indian Bustard

Answer. 1. Project Dodo

NEET Biology Notes – Biodiversity And Conservation

Biodiversity And Conservation Introduction

The occurrence of different types of genes, gene pools, species, habitats, and ecosystem in a particular place and various parts of the earth is called biodiversity (term popularized by Edward Wilson).

Currently, the number of predescribed species of all plants and animals is slightly more than 1.5 million.

Robed May estimated global species diversity at about 7 million (means only 22% of total diversity has been recorded so far).

Estimates Of Species Number On Earth And In India

  • Of the total estimate, more than 70% are animals while plants (including fungi) comprise no more than 22%. The most species-rich taxonomic group is insect (70% of animals).
  • The number of fungal species in the world is more than the combined total of fishes, amphibians, reptiles, and mammals.
  • No estimations are available for prokaryotes as consell giventional taxonomic methods are not suitable, and many of them are not culturable. We may accept bio-chemical/molecular criteria of estimation of diversity in this group.
  • India has 2.4% of world’s land, with 8.1% of global diversity. So, India is among 12 mega-diverse countries.
  • Nearly 45,000 plant species and twice as many animal species have been recorded from India.
  • Applying May’s method, more than 1,00,000 plant and 3,00,000 animals species are yet to be discovered and described.
  • Approximately 15,000 new species are discovered every year.

Read and Learn More NEET Biology Notes

Levels Of Biodiversity

There are three types of biodiversity:

  • Genetic diversity
    • It is a measure of variety in genetic information contained in the organism, e.g., 10-150 genes in virus, 450-700 genes in Mycoplasma, and 32,000-50,000 genes in Oryza sativa.
    • It enables a population to adapt to its environment, e.g., Rauwolfia vomitoria in Himalayan ranges.
    • It helps in the formation of ecotype.
    • It plays a key role in the process of speciation. It maintains diversity at the community level.
  • Species diversity
    • It is the variety of species within a region, e.g., Western Ghats are more diverse than Eastern Ghats.
    • Species richness is the number of species present within a unit area.
    • Species diversity is the product of species richness and species evenness.
    • Maximum/taxonomic diversity occurs where the species of taxonomically different groups occur in almost equal abundance.
    • Species evenness is the proportionate number of individuals of different species.
  • Community or ecosystem diversity

It is of three types (Whittaker):

    • a-diversity (within community diversity): It is also called local diversity. It is diversity within a community.
    • B-diversity (between community diversity): It is calculated by dividing y by a diversity. It is diversity between two communities.
    • y-diversity: It is also called regional diversity. It represents the total richness of species in all the habitats found within a region, geographical area, or landscape. For example, India is more diverse than Norway.

Patterns of Biodiversity

  • The degree of biodiversity shows two master gradients: latitudinal and altitudinal.
  • Biodiversity increases from high to low latitudes, i.e., from the poles to the equator.
  • Biodiversity is minimum in arctic, moderate in temperate, and maximum in tropical regions. With very few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) harbor more species than temperate or polar areas. Colombia located near the equator has nearly 1,400 species of birds while New York at 41° N has 105 species and Greenland at 71° N has only 56 species.
  • India with much of its land area in the tropical latitudes has more than 1200 species of birds. A forest in a tropical region such as Equador has up to 10 times as many species of vascular plants as in a forest of equal area in a temperate region such as the Midwest of the USA. The largely tropical Amazonian rain forest in South America has the greatest biodiversity on the earth.
  • It is home to more than 40,000 species of plants, 3000 of fishes, 1300 species of birds, 427 species of mammals, 427 species of amphibians, 378 species of reptiles, and more than 1,25,000 species of invertebrates. Scientists estimate that in these rain forests, there might be at least 2 million insect species waiting to be discovered and named.
  • Tropics show greater diversity because of the following reasons:
    • Speciation is generally a function of time. Unlike temperate regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and, thus, had a long evolutionary time for species diversification,
    • Tropical environments are less seasonal, are relatively more constant and predictable, can promote niche specialization, and lead to a greater species diversity.
    • Species-area relationships: Alexander Humboldt observed that within a region, species richness increased with increasing explored area, but only up to a limit. In fact, the relation between species richness and area for a wide variety of taxa (angiosperm plants, birds, bats, freshwater fishes) turns out to be a rectangular hyperbola.
      The relationship is a straight line described by the equationlog S = log C + Z log Awhere S is species richness, A is area, Z is the slope of the line (regression coefficient), and C is the Y-intercept.

NEET Biology Biodiversity And Conservation Species area relationship

  • Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or region. If we analyze the species area relationships among very large areas such as the entire continents, the slope of the line will be much steeper (Z values in the range of 0.6 to 1.2). For frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope is found to be 1.15.
  • Diversity decreases from lower to higher altitudes on a mountain, i.e., it is maximum at the base.
  • Conditions favoring growth do not induce biodiversity or speciation; it is called the paradox of enrichment.

Importance of Species Diversity to the Ecosystem

Community with more species is more stable. Stable community should not show too much variation in productivity per year and must be resistant or resilient to occasional disturbances by natural or anthropogenic agencies and alien species. Ecosystem health/balance will be severely affected if species. extinction (particularly key stone) occurs.

Biodiversity Conservation

  • Narrowly utilitarian aspect:
    • Pinus, Abies, and Boswellia are major sources of paper.
    • Pine resin is obtained from Pinus while damar is obtained from Shorea robusta.
    • Gums: Kuteera gum (Stericulia urens), Bengal kino gum (Butea monosperma), salai (Boswellia serrata), dhaora (Anogeissus latifolia), gum Arabic (Acacia senegal), etc.
    • Tannin sources: Uncaria (leaves and young branches), Acacia (bark), Juglans (bark), and Caesalpinia (wood and fruits).
    • Important dyes: Cutch/kattha (heartwood of Acacia catechu), henna (leaves of Lawsonia inermis), and haematoxylon (heartwood of Haematoxylon campechianum).
    • Plants can also be used to manufacture innumerable synthetic products called botanochemicals.

NEET Biology Biodiversity And Conservation Some important drugs

  • Broadly utilitarian aspect: Ecosystem services are important.
  • Ethical aspect: Every species has an intrinsic value.
  • Loss of Biodiversity IUCN Red List documents the extinctions of 784 species (including 338 vertebrates, 359 invertebrates, and 87 plants) in the last 500 years.
  • Some recent extinctions: Dodo (Mauritius), Quagga (Africa), Thylacine (Australia), Steller’s sea cow (Russia), and three subspecies (Bali, Javan, and Caspian) of tiger.
  • 27 species have disappeared in the last 20 years.
  • Presently, 12% birds species, 23% of all mammals, 32% of all amphibians, and 31% of all gymnosperms in the world are facing the threat of extinction (more than 15,500 species).
  • The sixth extinction is 100-1000 times faster.
  • This may lead to decline in plant production, lowered resistance, and increased variability in ecosystem processes, e.g., pest and disease cycle.

Causes of Biodiversity Losses

  • Important factors that cause loss of biodiversity are habitat loss, habitat fragmentation, disturbance, over exploitation, pollution, exotic species, intensive agriculture, and forestry (growing only exploitable forest plants).
  • Habitat destruction or loss is the primary cause of the loss of biodiversity (tropical rain forests were once covering 14% while now they cover 6% only), Amazon valley.
  • Habitat fragmentation reduces the core area and in- creases the edge area.
  • Dodo of Mauritius, messenger pigeon, Steller’s sea cow, and Tasmanian wolf have become extinct due to overexploitation. Heath hen disappeared due to hunting and habitat destruction.
  • Exotic (alien) species becoming invasive is considered another potent factor for the extinction of species.
  • Examples of some exotic species: Water hyacinth (Eichhornia crassipes), Lantana (Lantana camera), congress grass (Parthenium hysterophorus), Nile perch, Eupatorium (Eupatorium cdoratum), and African catfish (Clarias gariepinus).
  • Coextinction: For example, coevolved species.

Susceptibility to Extinction

Species more susceptible to extinction have the following population characteristics:

  • Large body size (e.g., rhinoceros and lion)
  • Small population size and low reproductive rate (e.g., giant panda and blue whale)
  • High trophic level in food chain (e.g., bald eagle and Bengal tiger)
  • Fixed habitat and migratory routes (e.g., whooping crane and blue whale)

IUCN Red List

  • World Conservation Union (WCU) which was formerly known as International Union for the Conservation of Nature and Natural Resources (IUCN), headquarter at Mc-den, Switzerland, has recognized eight Red List categories of species. They are extinct, extinct in wild, critically endangered, endangered, vulnerable, lower risk, data deficient, and not evaluated.
  • Critically endangered, endangered, and vulnerable species are called threatened species.
  • Rare species have a small population and these are nei- ther vulnerable nor endangered but are at risk.
  • A taxon is critically endangered when it is facing an extremely high risk of extinction in the wild in the immediate future.
  • A taxon is endangered when it is facing a high risk of extinction in the wild in the near future.
  • A taxon is vulnerable when it is facing a high risk of extinction in the wild in the medium term future.

NEET Biology Biodiversity And Conservation IUCN Red List

Conservation of Biodiversity

There are two types of conservation strategies: in situ (on site) and ex situ (off site).

In situ Conservation

  • Examples of protected areas: National parks, wildlife sanctuaries, and biosphere reserves.
  • World Conservation Monitoring Center has recognized 37,000 protected areas.
  • There are 448 wildlife sanctuaries and 90 national parks in India.
  • In wildlife sanctuaries, protection is given only to animal life while in national parks, both flora and fauna are protected.
  • The concept of biosphere reserves was launched under the MAB program of UNESCO (started in 1975).Total biosphere reserves in India are 14.
  • A biosphere reserve is made of core, buffer, and transition zones. In core or natural zone, no human activity is allowed.
  • Research and educational activities are allowed in buffer zone.
  • Activities such as settlements, cropping, grazing, forestry, and tourism are allowed in transition zone.

NEET Biology Biodiversity And Conservation Conservation of Biodiversity

Scared Grooves

  • Sacred forests (islands of pristine forests): Examples are forests of Jaintia and Khasi (Meghalaya), Aravalli (Rajasthan), Western Ghats (Maharashtra and Karnataka), Surguja, Chanda, and Bastar area (MP).
  • Sacred lakes: Examples are Pushkar lake in Rajasthan and Khecheopalri lake in Sikkim.
  • Sacred plants: Examples are Ocimum sanctum (tulsi), Elaeocarpus floribundus, and Ficus religiosa.

Ex situ Conservation Strategies

  • These include botanical gardens, zoological parks and wildlife safari parks, arboreta, aquaria, seed bank, DNA banks, tissue culture, horticultural trade, etc.
  • Cryopreservation (at temperature 196°C) is useful for conserving vegetatively propagated crops, e.g., potato. There are two types of cryopreservation:
    • Very rapid cooling (e.g., storing seeds)
    • Gradual cooling and simultaneous dehydration (e.g., tissue culture)
  • More than 1500 botanical gardens and arboreta and 800 professionally managed zoos are present around the world.

Biodiversity Hotspots

  • The concept was developed by Norman Myers in 1988. Spots with accelerated habitat loss are priority areas for in situ conservation. These areas show high species richness and high endemism.
  • India with 2.4% land area accounts approximately 8% species of the world.
  • Initially 25 terrestrial hotspots were identified glob- ally. But now the number is raised to 34 with an area of less than 2%.
  • Among 34, three (Western Ghats and Sri Lanka, Indo Burma, and Himalayas) are found in India. Eastern Himalayas are active center of evolution of many angiosperms and have many primitive angiosperms.
  • The protection of these areas can reduce mass extinction by almost 30%.
  • IUCN and WWF (World Wide Fund for Nature) are leading international organizations concerned with biodiversity conservation.

Some Abbreviations

  • NEERI: National Environment Engineering Research Institute
  • UNEP: United Nations Environment Program
  • CAZRI: Central Arid Zone Research Institute (Jodhpur)
  • BRP: Biosphere Reserve Program
  • MAB: Man and Biosphere
  • IBWL: Indian Board of Wild Life
  • CITES: Convention on International Trade in Endangered Species
  • CBD: Convention on Biological Diversity (The Earth Summit, 1992)

 

Assertion-Reasoning Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).

  1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).
  2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
  3. If Assertion is true but Reason is false, then mark (3).
  4. If both Assertion and Reason are false, then mark (4).

Question 1. Assertion: Western Ghats are included among the hot spots of biodiversity.

Reason: Western Ghats have greater amphibian diversity than Eastern Ghats.

Answer. 2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).

Question 2. Assertion: Tropical regions are more diversity-rich in comparison to temperate areas.

Reason: Availability of more solar energy directly affects the presence of more species in these areas.

Answer. 3. If Assertion is true but Reason is false, then mark (3).

Question 3. Assertion: The process of extinction is random.

Reason: Any species not adapted to environmental conditions cannot survive.

Answer. 4. If both Assertion and Reason are false, then mark (4).

Question 4. Assertion: Habitat destruction is the main reason of loss of biodiversity.

Reason: This actually causes the increase in edge area and reduction in core area.

Answer. 3. If Assertion is true but Reason is false, then mark (3).

Question 5. Assertion: Pristine forests are among in situ conservation strategies.

Reason: These are sacred grooves where biota is protected on site.

Answer. 1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

NEET Biology Multiple Choice Questions – Ecosystem

Ecosystem Multiple Choice Questions

Question 1. Which is not true regarding ecosystem?

  1. Self-sufficient unit.
  2. Cyclic exchange of materials between living beings and environment.
  3. Only requirement is input of energy.
  4. Characterized by a major vegetation type.

Answer. 4. Characterized by a major vegetation type.

Question 2. Which is not a structural aspect of ecosystem?

  1. Productivity
  2. Species composition
  3. Diversity
  4. Life cycle

Answer. 1. Productivity

Question 3. The amount of living material and nutrients present in different trophic levels and soils at any given time are called, respectively,

  1. Standing state and standing crop
  2. Standing crop and standing state
  3. Standing state and standing quality
  4. Biomass and standing crop

Answer. 2. Standing crop and standing state

Question 4. An ecosystem contains

  1. Green plants and animals
  2. Green plants and decomposers
  3. Green plants, animals, decomposers, and abiotic environment
  4. Producers and consumers

Answer. 3. Green plants, animals, decomposers, and abiotic environment

Question 5. When a habitat is subdivided into parts which show distinct properties, it is called

  1. Mini-habitat
  2. Micro-habitat
  3. Mega-habitat
  4. Macro-habitat

Answer. 2. Micro-habitat

Question 6. Which of the following are artificial aquatic ecosystems?

  1. Large dams and reservoirs
  2. Lakes and canals
  3. Aquarium and pond
  4. All of these

Answer. 4. All of these

Question 7. The amount of biogenetic nutrients present in the abiotic environment per unit area at any time is called

  1. Standing state
  2. Standing crop
  3. NPP
  4. Nutrients immobilization

Answer. 1. Standing state

Question 8. Which of the following is a functional aspect of an ecosystem?

  1. Species composition
  2. Inorganic nutrients
  3. Homeostasis
  4. Topography

Answer. 3. Homeostasis

Question 9. Which of the following are called key industry animals?

  1. Autotrophs
  2. Decomposers
  3. Herbivores
  4. Top carnivores

Answer. 3. Herbivores

Question 10. NPP is given by the formula

  1. NPP GPP × 100
  2. NPP = GDP – Secondary productivity
  3. NPP = GPP- Respiration rate
  4. NPP = GPP/100

Answer. 3. NPP = GPP- Respiration rate

Question 11. Which of the following ecosystems has the highest productivity?

  1. Tropical deciduous forest
  2. Temperate coniferous forest
  3. Tropical rain forest.
  4. Desert shrub

Answer. 3. Tropical rain forest.

Question 12. For NPP, energy captured is

  1. 1-5% of incident radiation
  2. 2-5% of PAR
  3. 0.8-4% of incident radiation
  4. 2-10% of PAR

Answer. 3. 0.8-4% of incident radiation

Question 13. Plant life is restricted in sea to

  1. Photic zone or euphotic zone
  2. Aphotic zone
  3. Abyssal area
  4. Continental shelf

Answer. 1. Photic zone or euphotic zone

Question 14. Gross primary productivity is

  1. Rate at which organic molecules are formed in an autotroph
  2. Rate at which organic molecules are used up by autotroph
  3. Storage of organic molecules in the body of an autotroph
  4. Rate at which organic molecules are transferred to the next higher trophic level

Answer. 1. Rate at which organic molecules are formed in an autotroph

Question 15. In tropical rain forest, most of the energy in ecosystem flows through

  1. Grazing food chain
  2. Detritus food chain
  3. Parasitic food chain
  4. Both (1) and (3)

Answer. 2. Detritus food chain

Question 16. The respiratory losses of producers, herbivores, and carnivores are, respectively,

  1. 10%, 20%, 30%
  2. 20%, 30%, 60%
  3. 20%, 40%, 80%
  4. Always 10%

Answer. 2. 20%, 30%, 60%

Question 17. Which of the following ecological pyramids can be both upright and inverted?

  1. Pyramid of number
  2. Pyramid of biomass
  3. Pyramid of energy
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 18. Which of the following ecological pyramids is the most representative of the functional characteristics of an eco-system?

  1. Pyramid of number
  2. Pyramid of biomass
  3. Pyramid of energy
  4. All are equally representative

Answer. 3. Pyramid of energy

Question 19. (NPP/GPP) × 100 is

  1. Assimilation efficiency
  2. Net production efficiency
  3. Ecological efficiency
  4. Photosynthetic efficiency

Answer. 2. Net production efficiency

Question 20. Which is not true for humus?

  1. Dark colored amorphous substance
  2. Highly resistant to microbial action
  3. Acts as reservoir of nutrients and increases water holding capacity of soil
  4. Degradation product of proteins and fats and produced by the process of mineralization

Answer. 4. Degradation product of proteins and fats and produced by the process of mineralization

Question 21. Nutrient immobilization

  1. Prevents leaching of nutrients
  2. Is incorporation of nutrients in microbes.
  3. Is covalent linking of nutrients with one another
  4. More than one option is correct

Answer. 4. More than one option is correct

Question 22. If producer is a large tree that supports a number of herbivorous animals which are further attacked by ectoparasites, the pyramid of number shall be

  1. Inverted
  2. Upright
  3. Irregular
  4. Spindle shaped

Answer. 1. Inverted

Question 23. Ecological pyramids are also called

  1. Pyramids of number
  2. Eltonian pyramids
  3. Pyramids of energy
  4. Pyramids of biomass

Answer. 2. Eltonian pyramids

Question 24. A food web

  1. Increases the variety of food at each trophic level
  2. Delicately balances the inter-relations amongst organisms
  3. Decreases the variety of food but increases the quantity of food at each trophic level
  4. Increases the variety as well as the quantity of food at each trophic level

Answer. 4. Increases the variety as well as the quantity of food at each trophic level

Question 25. Ten percent law of energy transfer in a food chain was enunciated by

  1. Elton
  2. Lindeman
  3. Haeckel
  4. SchimperAnswer. 2. Lindeman

Question 26. The importance of ecosystem lies in

  1. Flow of energy
  2. Cycling of materials
  3. Both (1) and (2)
  4. Consumers

Answer. 3. Both (1) and (2)

Question 27. Earth is an

  1. Open system
  2. Closed system
  3. Both (1) and (2)
  4. None of these

Answer. 3. Both (1) and (2)

Question 28. Biogeochemical cycle having a small gaseous component is found in

  1. Phosphorus
  2. Nitrogen
  3. Carbon
  4. Sulfur

Answer. 4. Sulfur

Question 29. Annually, 1 ha of a healthy forest will

  1. Produce 10 ton of O2 and absorb 10 ton of CO2
  2. Produce 20 ton of O, and absorb 20 ton of CO2
  3. Produce 10 ton of O, and absorb 30 ton of CO2
  4. Produce 30 ton of O, and absorb 30 ton of CO2

Answer. 3. Produce 10 ton of O, and absorb 30 ton of CO2

Question 30. How many overlapping water cycles are found in nature?

  1. Two
  2. Three
  3. One
  4. There is no overlapping cycle

Answer. 1. Two

Question 31. Phosphates remain outside the natural cycle for a long time

  1. When they form compounds with metals
  2. When they are incorporated in bones and teeth
  3. When the bodies of the organisms excrete and decompose
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 32. Human dominated environment is called

  1. Biosphere
  2. Noosphere
  3. Socio-cultural environment
  4. None of these

Answer. 2. Noosphere

Question 33. Energy requirement for the maintenance of body with successively higher trophic level

  1. Decreases
  2. Increases
  3. Remains same
  4. Is always 10%

Answer. 2. Increases

Question 34. In which of the following biogeochemical cycles is atmospheric phase absent/negligible?

  1. Nitrogen
  2. Sulfur
  3. Phosphorus
  4. Water

Answer. 3. Phosphorus

Question 35. Stratification is well developed in

  1. Tropical rain forests
  2. Grasslands
  3. Alpine vegetations
  4. Temperate forests

Answer. 1. Tropical rain forests

Question 36. An orderly sequence of community development on an area is called

  1. Succession
  2. Cover
  3. Establishment
  4. Diversity

Answer. 1. Succession

Question 37. The terminal stage of a successional process is called

  1. Final stage
  2. Climax stage
  3. Seral stage
  4. Pioneer stage

Answer. 2. Climax stage

Question 38. If the pioneer stage is dominated by autotrophs, then the succession is called

  1. Allogenic
  2. Autogenic
  3. Autotrophic
  4. Heterotrophic

Answer. 3. Autotrophic

Question 39. Which is not a characteristic of sera stages?

  1. Simplified food chain
  2. Few and generalized niches
  3. Low NPP
  4. Low energy use efficiency

Answer. 3. Low NPP

Question 40. Succession stage that occurs on a bare rock is called

  1. Psammosere
  2. Xerosere
  3. Lithosere
  4. Haloscre

Answer. 3. Lithosere

Question 41. Serial changes in the previously sterile or total barren area are called

  1. Climatic climax
  2. Secondary succession
  3. Primary succession
  4. Sere

Answer. 3. Primary succession

Question 42. Pond is an example of ecosystem.

  1. Artificial
  2. Natural
  3. Forest
  4. Grassland

Answer. 2. Natural

Question 43. Which of the following is the most productive ecosystem?

  1. Estuary
  2. Open sea
  3. Desert
  4. MountainAnswer. 1. Estuary

Question 44. The pyramid of energy in a forest ecosystem is

  1. Always upright
  2. Always inverted
  3. Both upright and inverted
  4. None of the above

Answer. 1. Always upright

Question 45. The importance of ecosystem is

  1. Flow of energy
  2. Cycling of materials
  3. Both (1) and (2)
  4. None of the above

Answer. 3. Both (1) and (2)

Question 46. Which is the correct path of energy flow in an ecosystem?

  1. Producers → Carnivores Herbivores → Decomposers
  2. Producers → Herbivores → Carnivores → Decomposers
  3. Herbivores → Carnivores → Producers → Decomposers
  4. Herbivores → Producers → Carnivores → Decomposers

Answer. 2. Producers → Herbivores → Carnivores → Decomposers

Question 47. The number of primary producers within a specified area would be maximum in

  1. Grassland ecosystem
  2. Forest ecosystem
  3. Pond ecosystem
  4. Deserts

Answer. 3. Pond ecosystem

Question 48. A food chain starts with

  1. Nitrogen fixation organisms
  2. Photosynthesizing organisms
  3. Respiration
  4. Decomposers

Answer. 2. Photosynthesizing organisms

Question 49. Nepenthes is a

  1. Primary producer
  2. Consumer
  3. Both primary producer and consumer
  4. None of the above

Answer. 3. Both primary producer and consumer

Question 50. Biological equilibrium is found among

  1. Producers and consumers
  2. Producers and decomposers
  3. Producers, consumers, and decomposers
  4. Producers and light

Answer. 1. Producers and consumers

Question 51. The number of individuals of a species in a particular ecosystem at a given time remains constant due to

  1. Man
  2. Parasites
  3. Predators
  4. Available food

Answer. 4. Available food

Question 52. The two components of an ecosystem are

  1. Biotic and abiotic
  2. Plants and animals
  3. Weeds and microorganisms
  4. Plants and light

Answer. 1. Biotic and abiotic

Question 53. The pyramid of number in a grassland ecosystem is

  1. Linear
  2. Upright
  3. Irregular
  4. Inverted

Answer. 2. Upright

Question 54. The cycling of elements in an ecosystem is called.

  1. Chemical cycle
  2. Biogeochemical cycle
  3. Geological cycle
  4. Geochemical cycle

Answer. 2. Biogeochemical cycle

Question 55. Which of the following bacteria has potential for nitrogen fixation?

  1. Nitrosomonas
  2. Nitrobacter
  3. Nitrosococcus
  4. Rhizobium

Answer. 4. Rhizobium

Question 56. Ecosystem has

  1. Plant and animal
  2. Air and H2O
  3. Soil and light
  4. Biotic and abiotic components

Answer. 4. Biotic and abiotic components

Question 57. Sal and teak are found in

  1. Tropical rain forest
  2. Tropical deciduous forest
  3. Temperature board leaf forest
  4. Temperature needle leaf forest

Answer. 2. Tropical deciduous forest

Question 58. Decomposers are

  1. Autotrophs
  2. Heterotrophs
  3. Organotrophs
  4. Autoheterotrophs

Answer. 2. Heterotrophs

Question 59. During food chain, the maximum energy is stored in

  1. Producers
  2. Decomposers
  3. Herbivores
  4. Carnivores

Answer. 1. Producers

Question 60. In the phosphorus cycle, weathering makes phosphate available first to

  1. Decomposers
  2. Consumers
  3. Producers
  4. All the above

Answer. 3. Producers

Question 61. In a food chain, the total amount of living material is depicted by

  1. Pyramid of biomass
  2. Pyramid of energy
  3. Pyramid of number
  4. Trophic levels

Answer. 1. Pyramid of biomass

Question 62. Nitrates are converted to nitrogen by

  1. Nitrogen fixing bacteria
  2. Ammonification bacteria
  3. Denitrifying bacteria
  4. Nitrifying bacteria

Answer. 3. Denitrifying bacteria

Question 63. In pond ecosystem, diatoms represent

  1. Producers
  2. Primary consumers
  3. Secondary consumers
  4. Tertiary consumers

Answer. 1. Producers

Question 64. Pyramids of biomass in pond ecosystem are

  1. Inverted
  2. Upright
  3. Linear
  4. Irregular

Answer. 1. Inverted

Question 65. Lion is kept under in Eltonian pyramid as

  1. Producer
  2. Primary consumer
  3. Secondary consumer
  4. Tertiary consumer

Answer. 4. Tertiary consumer

Question 66. Bacteria and fungi developing on dead decaying organisms are

  1. Parasites
  2. Commensals
  3. Saprophytes
  4. Symbionts

Answer. 3. Saprophytes

Question 67. Phytoplanktons are important biotic components of

  1. Grassland
  2. Pond ecosystem
  3. Forest ecosystem
  4. None of these

Answer. 2. Pond ecosystem

Question 68. Which ecological pyramid can never occur in an inverted form?

  1. Pyramid of number
  2. Pyramid of biomass
  3. Pyramid of energy
  4. Pyramid of species richness

Answer. 4. Pyramid of species richness

Question 69. Peacock eats snake and snake eats insect while insect eats green plant. Then the position of peacock is

  1. Primary producer
  2. Secondary producer
  3. Decomposer
  4. Top at the apex of food pyramid

Answer. 1. Primary producer

Question 70. Source of energy in an ecosystem is

  1. Sun
  2. ATP
  3. Sugar made by plant
  4. Green plant

Answer. 3. Sugar made by plant

Question 71. Legume plants are important for atmosphere because they

  1. Help in NO2 fixation
  2. Do not help in NO2 fixation
  3. Increase soil fertility
  4. All of these

Answer. 4. All of these

Question 72. Tropical dense forests are due to

  1. Low rainfall and low temperature
  2. High rainfall and low temperature
  3. Low rainfall and high temperature
  4. High rainfall and high temperature

Answer. 1. Low rainfall and low temperature

Question 73. Energy enters in food chain by

  1. Producer
  2. Primary consumers
  3. Secondary consumers
  4. Tertiary consumers

Answer. 1. Producer

Question 74. In an ecosystem,

  1. Primary producers are more than primary consumers
  2. Primary consumers are larger than primary producers
  3. Secondary consumers are larger than primary producers
  4. Primary consumers least depend on primary producers

Answer. 1. Primary producers are more than primary consumers

Question 75. In which type of forest is humus formed by dry and dead leaves?

  1. Coniferous forest
  2. Deciduous forest
  3. Tundra forest
  4. Alpine

Answer. 2. Deciduous forest

Question 76. A pond is a

  1. Biome
  2. Natural ecosystem
  3. Artificial ecosystem
  4. Community of plants and animals

Answer. 2. Natural ecosystem

Question 77. The importance of ecosystem lies in

  1. Energy flow
  2. Cycling of materials
  3. Both
  4. None

Answer. 3. Both

Question 78. The concept of ecological pyramid was given by

  1. Odum
  2. Elton
  3. Darwin
  4. Reiter

Answer. 2. Elton

Question 79. Stratification is found in

  1. Tundra
  2. Tropical forest
  3. Deciduous forest
  4. Desert

Answer. 2. Tropical forest

Question 80. The driving force of ecosystem is

  1. Producers
  2. Plants with carbohydrates
  3. Biomass
  4. Solar energy

Answer. 4. Solar energy

Question 81. Ecosystem creates

  1. Food chain
  2. Food web
  3. Any of the two
  4. None

Answer. 3. Any of the two

Question 82. The term ecosystem was coined by

  1. P. Maheshwari
  2. Tansley
  3. R. Mishra
  4. P. Odum

Answer. 2. Tansley

Question 83. The importance of ecosystem lies in

  1. Flow of energy
  2. Cycling of materials
  3. Both (1) and (2)
  4. None of the above

Answer. 3. Both (1) and (2)

Question 84. A pond is a

  1. Biome
  2. Natural ecosystem
  3. Artificial ecosystem
  4. Community of plants and animals

Answer. 2. Natural ecosystem

Question 85. Which biotic components mainly help in the recycling of minerals?

  1. Producers
  2. Consumers
  3. Decomposers
  4. All the above

Answer. 3. Decomposers

Question 86. Path of energy flow in an ecosystem is

  1. Herbivorous → Producer → Carnivorous → Decomposer
  2. Herbivorous → Carnivorous → Producer → Decomposer
  3. Producer → Carnivorous → Herbivorous → Decomposer
  4. Producer → Herbivorous → Carnivorous → Decomposer

Answer. 4. Producer → Herbivorous → Carnivorous → Decomposer

Question 87. The number of primary producers in a specified area would be the maximum in

  1. Pond ecosystem
  2. Grassland ecosystem
  3. Forest ecosystem
  4. Desert ecosystem

Answer. 1. Pond ecosystem

Question 88. Carbon cycle includes (the following is a logical sequence)

  1. Producer → Consumer → Decomposer
  2. Decomposer → Consumer → Producer
  3. Producer → Decomposer → Consumer
  4. Consumer → Producer → Decomposer

Answer. 1. Producer → Consumer → Decomposer

Question 89. The bulk of nitrogen in nature is fixed by

  1. Lightening
  2. Chemical industries
  3. Denitrifying bacteria
  4. Symbiotic bacteria

Answer. 4. Symbiotic bacteria

Question 90. Hydrological cycle is controlled by

  1. Grasslands
  2. Forests
  3. Planktons
  4. Epiphytes

Answer. 2. Forests

Question 91. In India, the temperate, evergreen type of vegetation is found mostly in

  1. Western Himalayas above 3500 m
  2. Eastern and Western Himalayas less than 3500 m
  3. Rajasthan and South Punjab
  4. Western Ghats and Assam

Answer. 2. Eastern and Western Himalayas less than 3500 m

Question 92. Savannahs are

  1. Tropical rain forest
  2. Desert
  3. Grassland with scattered trees
  4. Dense forest with close canopy

Answer. 4. Dense forest with close canopy

Question 93. Biosphere refers to

  1. Plants of the world
  2. Special plants
  3. Area occupied by living beings
  4. Plants of a particular area

Answer. 3. Area occupied by living beings

Question 94. Acacia, Prosopis, and Caparis belong to

  1. Deciduous forest
  2. Tropical forest
  3. Thorn forest
  4. Evergreen forest

Answer. 3. Thorn forest

Question 95. The total amount of energy trapped by green plants in food is called

  1. Gross primary production
  2. Net primary production
  3. Standing crop
  4. Standing state

Answer. 1. Gross primary production

Question 96. In which biome may a new plant adapt soon?

  1. Tropical rain forest
  2. Desert
  3. Mangrove
  4. Sea island

Answer. 1. Tropical rain forest

Question 97. Percentage energy transferred to higher trophic level in food chain is

  1. 1%
  2. 10%
  3. 90%
  4. 100%

Answer. 2. 10%

Question 98. What is the reason for the highest biomass in aquatic ecosystem?

  1. Nanoplankton, blue green algae, green algae
  2. Sea grass and slime molds
  3. Benthonic and brown algae
  4. Diatoms

Answer. 3. Benthonic and brown algae

Question 99. Which of the following is a correct pair?

  1. Cuscuta – Parasite
  2. Dischidia – Insectivorous
  3. Opuntia – Predator
  4. Capsella – Hydrophyte

Answer. 1. Cuscuta – Parasite

Question 100. Bamboo plant is growing in a tropical rain forest. Then what will be its trophic level?

  1. First trophic level (T1)
  2. Second trophic level (T2)
  3. Third trophic level (T3)
  4. Fourth trophic level (T4)

Answer. 1. First trophic level (T1)

Question 101. Which of the following is expected to have the highest value (g/m2/yr) in a grassland ecosystem?

  1. Tertiary production
  2. Gross production (GP)
  3. Net production (NP)
  4. Secondary production

Answer. 2. Gross production (GP)

Question 102. An ecosystem which can be easily damaged but can re- cover after some time if the damaging effect stops will have

  1. High stability and low resilience
  2. Low stability and low resilience
  3. High stability and high resilience
  4. Low stability and high resilience

Answer. 4. Low stability and high resilience

Question 103. Which one of the following pairs is mismatched?

  1. Savanna – Acacia trees
  2. Coniferous forest – Evergreen trees
  3. Tundra – Permafrost
  4. Prairies – EpiphytesAnswer. 4. Prairies – Epiphytes

Question 104. Which one of the following is not used for the construction of ecological pyramids?

  1. Rate of energy flow
  2. Fresh weight
  3. Dry weight
  4. Number of individuals

Answer. 2. Fresh weight

Question 105. Which one of the following ecosystem types has the highest annual net primary productivity?

  1. Temperate deciduous forest
  2. Tropical rain forest
  3. Tropical deciduous forest
  4. Temperate evergreen forest

Answer. 2. Tropical rain forest

Question 106. Quercus species is the dominant component in

  1. Scrub forests
  2. Tropical rain forests
  3. Temperate deciduous forests
  4. Alpine forests

Answer. 3. Temperate deciduous forests

Question 107. Consider the following statements concerning food chain?

(a) Removal of 80% tigers from an area resulted in greatly increased growth of vegetation.

(b) Removal of most of the carnivores resulted in an increased population of deers.

(c) The length of food chains is generally limited to 3-4 trophic levels due to energy loss.

(d) The length of food chains may vary from 2 to 8 trophic levels.

Which of the above two statements are correct?

  1. (a), (c)
  2. (a), (b)
  3. (b), (c)
  4. (c), (d)

Answer. 3. (b), (c)

Question 108. The slow rate of decomposition of fallen logs in nature is due to their

  1. Anaerobic environment around them
  2. Low cellulose content
  3. Low moisture content
  4. Poor nitrogen content

Answer. 3. Low moisture content

Question 109. Which one of the following types of organisms occupies more than one trophic level in a pond ecosystem?

  1. Frog
  2. Phytoplankton
  3. Fish
  4. Zooplankton

Answer. 3. Fish

Question 110. Study the four statements, (A)-(D), given and select the two correct ones out of them:

(A) A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers.

(B) Predator starfish helps in maintaining the species diversity of some invertebrates.

(C) Predators ultimately lead to the extinction of prey species.

(D) The productions of chemicals such as nicotine and strychnine by plants are metabolic disorders.

The two correct statements are

  1. (A) and (D)
  2. (A) and (B)
  3. (B) and (C)
  4. (C) and (D)

Answer. 2. (A) and (B)

Question 111. The biomass available for consumption by herbivores and decomposers is called

  1. Net primary productivity
  2. Secondary productivity
  3. Standing crop
  4. Gross primary productivity

Answer. 1. Net primary productivity

Question 112. Which of the following is one of the characteristics of a biological community?

  1. Stratification
  2. Natality
  3. Mortality
  4. Sex-ratio

Answer. 1. Stratification

Question 113. Identify the possible link “A” in the following food chain:

Plant → Insect → Frog → “A” → Eagle

  1. Wolf
  2. Cobra
  3. Parrot
  4. Rabbit

Answer. 2. Cobra

Quercus 114. In an area where DDT had been used extensively, the population of birds declined significantly because

  1. Earthworms in the area got eradicated
  2. Cobras were feeding exclusively on birds
  3. Many eggs laid by birds did not hatch
  4. Birds stopped laying eggs

Answer. 3. Many eggs laid by birds did not hatch

Question 115. The upright pyramid of numbers is absent in

  1. Forest
  2. Lake
  3. Grassland
  4. Pond

Answer. 1. Forest

Question 116. An imaginary pyramid of numbers is given. What can be one of the possibilities about certain organisms at some of the different levels?

NEET Biology Ecosystem Question 76

  1. Level PP is phytoplanktons in sea and top level TC is whale.
  2. Level one PP is pipal trees and level SC is sheep
  3. Level PC is rats and level SC is cats.
  4. Level PC is insects and level SC is small insectivorous birds.

Answer. 4. Level PC is insects and level SC is small insectivorous birds.

Quercus 117. Which one of the following is not a functional unit of an ecosystem?

  1. Decomposition
  2. Productivity
  3. Stratification
  4. Energy flow

Answer. 3. Stratification

Question 118. Which one of the following is not a gaseous biogeochemical cycle in ecosystem?

  1. Phosphorus cycle
  2. Nitrogen cycle
  3. Carbon cycle
  4. Sulfur cycle

Answer. 1. Phosphorus cycle

Question 119. The rate of formation of new organic matter by rabbit in grassland is called

  1. Net productivity
  2. Secondary productivity
  3. Net primary productivity
  4. Gross primary productivity

Answer. 2. Secondary productivity

NEET Biology Notes – Ecosystem

Ecosystem Introduction

According to Tansley (who also coined the term ecosystem), the sum total of interaction between living (biotic) and non-living (abiotic) components which is capable of independent existence is called an ecosystem.

Some other terms used for ecosystem are biocoenosis (by C. Mobius), microcosm (by Forbes), and geobiocoenosis (by Sukhachev).

Important Facts About Ecosystem

  • The flow of energy is from producer to consumers.
  • Cycling of matter takes place between biotic and abiotic components.
  • There exists functional relationship between organisms and the environment.
  • There is a great deal of biotic diversity.
  • Homeostasis (self-regulation): The ecosystem has the capacity to overcome forces which tend to disturb the balance of the ecosystem (resilience).
  • Incomplete ecosystem: An ecosystem lacking one or more structural components is called an incomplete ecosystem, e.g., deep sea and freshly formed rain water pond ecosystem.
  • Artificial ecosystems: These are man-made ecosystems. Examples are modern agriculture, dams, zoo-logical parks, plantations, aquacultures, etc.
  • The characteristics of artificial ecosystems are as follows:
    • Artificial ecosystems do not possess self-regulatory mechanism.
    • These have little diversity.
    • The food chain is simple.
    • Productivity is high.
    • There is little cycling of nutrients.

Structure And Function Of Ecosystem

Structure of Ecosystem

The structure of ecosystem depends upon the following components:

  • Species diversity components of ecosystem
  • Species composition
  • Life cycle
  • Stratification

Read and Learn More NEET Biology Notes

NEET Biology Ecosystem Structure of Ecosystem

Function of Ecosystem

The edaphic functional components of ecosystem are studied with the following aspects:

  • Productivity
  • Mineral cycling
  • Energy flow
  • Food chain and web slopes
  • Efficiency
  • Biotic interrelationships
  • Homeostasis
  • Ecoregulation

Homeostasis in Ecosystem

Ecosystem maintains functional balance or homeostasis among different components. It is due to the following reasons:

  • Carrying capacity
  • Nutrient cycling
  • Self-regulation
  • Feedback

Stratification

Stratification is the structure or recognizable pattern in the spatial arrangement of the members of communities. More specifically, stratification represents vertical zonation in the community. For example, in grassland communities, there is subterranean floor containing basal portions of vegetation. However, stratification in a forest community is the most complicated where as many as five vertical subdivisions may be recognized. These vertical subdivisions are as follows:

  • Subterranean
  • Forest floor
  • Herbaceous vegetation
  • Shrubs
  • Trees

Boundaries of Ecosystems

An ecosystem is generally regarded as a self-sufficient unit and a separate entity. However, it never operates in isolation. Boundaries between one ecosystem and another are indistinct and overlapping and all ecosystems on the earth are joined together to form a single global ecosystem known as biosphere, Some exchange of materials and energy always occurs between different ecosystems through geological, climatic, or biological processes.

Productivity Of Ecosystem

  • Coral reefs, tropical rain forests, and sugarcane are most productive.
  • Deserts and deep sea ecosystems are least productive.

Energy

An ecosystem is maintained by the flow of energy derived from the sun. Energy trapped by plants varies from ecosystem to ecosystem energy absorption at different levels.

NEET Biology Ecosystem Energy

  • Gross primary productivity (GPP): It is the rate of organic matter synthesized by producers per unit area per unit time.
  • Net primary productivity (NPP): It is the rate of organic matter built up or stored by producers in their bodies per unit time and area. Net productivity is equal to gross primary productivity minus loss due to respi- ration and other reasons.
    NPP = GPP- Respiratory loss
    The annual NPP of the whole biosphere is approximately 170 billion ton (dry wt.) of organic matter. Despite occupying about 70% of the surface, the productivity of oceans is only 55 billion ton.
  • Secondary productivity: The rate of increase in energy containing organic matter or biomass by heterotrophs or consumers per unit time and area is known as secondary productivity.
  • Community productivity: It is the rate of net synthesis of built-up of organic matter by a community per unit time and area.
  • Ecological efficiency/trophic level efficiency: The percentage of energy converted into biomass by a higher trophic level over the energy of food resources available at the lower trophic level is called ecological efficiency.
  • Photosynthetic efficiency = Gross primary productivity/Incident total solar radiation
  • Net production efficiency = Net primary productivity/Gross primary productivity x 100

Decomposition

Decomposition is the process of physical and chemical breakdown of complex organic remains by organisms called decomposers, so as to produce inorganic raw materials (CO2, H2O, minerals, etc.) for recycling. The major site for decomposition is the upper layer of soil in terrestrial habitats and the bottom of water bodies. Freshly deposited organic matter constitutes raw material and is called litter. Detritus is degrading dead organic matter.

It is differentiated into above-ground and below-ground detritus. Above-ground detritus consists of dried plant parts (leaves, twigs, bark, and flowers), excreta, and dead remains of animals. Below-ground detritus is also called root detritus because it is mainly composed of dead roots. Underground organisms and their excreta also form a pan of below-ground detritus.

Decomposition Processes

Three types of processes occur simultaneously during the decomposition of detritus, viz. fragmentation, leaching, and catabolism.

  • Fragmentation of detritus: Small invertebrate animals, called detrivores, feed on detritus, e.g., earthworms and termites. They bring about its frag- mentation. A part of detritus eaten by detrivores comes out in a highly pulverized state in their feces. Due to fragmentation during eating and pulverization in digestive tracts, detritus is changed into fine particles which have a large surface area.
  • Leaching: Parts of soluble substances present in the fragmented and decomposing detritus (e.g., sugars and inorganic nutrients) get leached to the upper layers of soil by percolating water.
  • Catabolism: It is carried out by saprotrophic bacteria and fungi. They secrete digestive enzymes over the fragmented detritus. The enzymes change complex organic compounds into simple compounds. Inorganic substances are also released in the process.

The rate of catabolic action or breakdown of different complex substances is different. This differential decomposition produces two substances: humus and inorganic nutrients in processes, respectively, called humification and mineralization, which occurs in soil.

  • Humification: It is the process of particle decomposition of detritus to form humus. Humus is a dark-colored amorphous partially decomposed organic matter rich in cellulose, lignin, tannins, resin, etc., because of its highly resistant nature. It is slightly acidic, colloidal, and functions as a reservoir of nutrients.
  • Mineralization: It is the release of inorganic substances (e.g., CO2, H2O, and minerals) from organic matter during the process of decomposition. These are formed along with simple and soluble organic substances when digestive enzymes are poured over organic matter by saprotrophic microbes.

Factors Affecting Decomposition

The rate of decomposition of detritus is controlled by a number of factors.

  • Chemical nature of detritus: The decomposition of detritus is slow if it contains lignin, chitin, tannins (phenolics), and cellulose. It is rapid if detritus possesses more of nitrogenous compounds (such as proteins and nucleic acids) and reserves carbohydrates.
  • Soil pH: Detrivores are fewer in acidic soils. Microbial activity is also low in such soils. Therefore, the rate of decomposition of organic matter is slow in acidic soils. Partially decomposed organic matter piles up over such soils. Detrivores are abundant in neutral and slightly alkaline soils while decomposer microbes are rich in neutral and slightly acidic soils.
  • Temperature: At a temperature of more than 25°C, decomposers are very active in soils having good moisture and aeration. In humid tropical regions, it does not take more than 3-4 months for complete decomposition of detritus. However, under low temperature conditions (> 100°C) of soils, the rate of decomposition is very slow even if moisture and aeration are optimum.
  • Moisture: Optimum moisture helps in quicker decomposition of detritus. Reduction in moisture reduces the rate of decomposition in areas of prolonged dryness such as tropical deserts where otherwise the temperature is quite high. Excessive moisture also impedes decomposition.
  • Aeration: It is required for the activity of decomposers and detrivores. A reduced aeration will slow down the process of decomposition.

Energy Flow

  • Food chain: It is a sequence of living organisms in which one organism consumes another due to interdependence.
  • Key industry animals: These are herbivores who convert plant matter into animal matter.
    There are three types of industry animals:

    • Grazing food chain (GFC)/predator food chain major in aquatic ecosystems
    • Detritus food chain-major in terrestrial ecosystems
    • Parasitic food chain
  • DFC
    • Source of energy is detritus not sun.
    • It is composed of a long chain of detritus-eating organisms (detritivores).
    • In some ecosystems (e.g., tropical rain forests), more energy flows in this chain than in the GFC.
  • Food web: The interconnected food chains operating in an ecosystem are called food webs. It is, thus, a collection of food chains.
  • Standing state or standing quality: It is the amount of inorganic substances present in an ecosystem per unit area at a given time.
  • Standing crop: It is the amount of living material present in different trophic levels at a given time. It is commonly expressed as the number of organisms per unit area.

Ecological Pyramids

Ecological pyramids (Eltonian pyramids) were developed by Charles Elion in 1927. They are graphical representation of dif- ferent ecological parameters. In the pyramid, producers form the base and top carnivores the tip. The pyramid can be upright, inverted, or spindle shaped. These are of three types:

  • Pyramid of number: Upright for grassland and pond and inverted for parasitic ecosystem.
  • Pyramid of biomass: Upright for terrestrial habitats and inverted for aquatic habitats.
  • Pyramid of energy: Always upright.

Ecological Succession (By Hult)

Every community undergoes a series of changes until a group of organisms is established which can live and reproduce most successfully in the area. This is called biotic succession. A biotic community normally undergoes continuous changes. The interactions among organisms in a community collectively constitute biotic factors; these influence the structure, composition, and function of a community.

Generally, a definite and orderly sequence of communities gradually appears in an area over a period of time. The first community which appears on an area is called pioneer community. A specific sequence of development of a community is related to a particular set of physical and chemical conditions. This is known as a sere, and is composed of a number of biotic communities replacing each other in the course of time called seral communities. The last community is called climax or a climatic climax (as it mostly depends upon climate).

  • Primary succession: It occurs on biologically sterile area which has no record of any previous vegetation. The conditions are extreme and it takes very long time (1000 years) to complete, i.e., establishing climax community, e.g., newly created pond.
  • Secondary succession: It occurs on an area that was previously occupied by vegetation and was later destroyed by fire, deforestation, over-grazing, volcanic eruptions, and floods. Humus is already present and environment is not so hostile. Therefore, it takes lesser time.
  • Autogenic and allogenic succession: When a community replaces the other due to the modification of the environment by the community itself, the succession is called autogenic. On the contrary, when a community replaces the other largely due to the forces other than the effects of communities on the environment, the succession is said to be allogenic.
  • Autotrophic and heterotrophic succession: Autotrophic succession is characterized by early dominance of autotrophic organisms and begins in predominantly inorganic environment. On the contrary, heterotrophic succession is characterized by early dominance of heterotrophs and begins in a predominantly organic environment.

Process of Succession

Major steps in a primary autotrophic succession are as follows:

  • Nudation: An area is exposed.
  • Migration: The process of dispersal of seeds, spores, and other structures of propagation of the species to bare area is known as migration.
  • Germination: It occurs when conditions are favorable.
  • Ecesis: Successful germination of propagules and their establishment in a bare area is known as ecesis.
  • Colonization and aggregation: After ecesis, the individuals of the species increase in number as a result of reproduction.
  • Competition and co-action: Due to limited resources, species show both inter and intraspecific competition. This results in the elimination of unsuitable and weaker plants.
  • Invasion: Various other types of plants try to establish in the spaces left by the elimination of plants due to competition.
  • Reaction: The newly arrived plants interrupt with the existing ones. As a result of reaction, the environment is modified and becomes unsuitable for the existing community which sooner or later is replaced by another community.
  • Stabilization: It is the process when the final climax community becomes more or less stabilized for a longer period of time and can maintain itself in equilibrium with the climate of the area. As compared to the seral stage community, the climax community has larger size of individuals, complex organization, complex food chains and food webs, more efficient energy use, and more nutrient conservation.

Major Trends During Succession

  • There is an increase in structural complexity.
  • Diversity of species tends to increase.
  • Biomass and standing crop increase.
  • There is a decrease in net community production. There is an increase in non-living matter.
  • Food chain relationship becomes complex.
  • Niche becomes specific and narrower.
  • Energy use and nutrient conservation efficiency increase.
  • Stability increases.

Contents of Ecological Succession

  • Lithosere (succession on desert/rock):
    • Lichen stage: Wind borne lichen propagules settle on the wet rock surface soon after rain or heavy dew. They develop attaching structure rhizenes. The pioneer lichens are usually crustose lichens, e.g., Graphis, Rhizocarpon, etc. They secrete lichen acids and carbonic acid. The acids slowly corrode rock surface and release minerals required for the proper growth of larger lichens, i.e., foliose lichens, e.g., Parmelia.
    • Moss stage: Foliose lichens growing on rocks make the conditions favorable for the growth of hardy mosses. Ultimately, the spot becomes suitable for invasion by the next stage (e.g., Hypnum and Bryum).
    • Annual grass stage: The mat formed by mosses on the partially fragmented rock becomes sufficiently moist during the rainy season for the germination of seeds of annual grasses and other hardy herbs, e.g., Aristida, Poa, and Eleusine.
    • Perennial grass stage: Annual grasses are replaced by perennial grasses due to increased moisture and soil in the rock crevices. The perennial grasses have runners and rhizomes which rapidly spread the grasses, e.g., Cymbopogon and Heteropogon.
    • Shrub stage: Seeds and rhizomes of xerophytic shrubs invade the area occupied by perennial grasses, e.g., Zizyphus, Capparis, Rhus, and Rubus. Shrubs are larger and their roots reach greater depth causing further cracks in the rocky substratum and, hence, helping in more soil formation.
    • Climax community: Several hardy and light demanding trees grow in the area occupied by shrubs. Slowly the environment becomes more moist and shadier so that plants. of climax community spread in the area. The type of climax community depends upon the climate. Therefore, it is also called climatic climax community.
  • Hydrosere (succession on pond):
    • Plankton stage: It is the pioneer stage of hydrosere. Planktons reach the water body through wind or animals. The first to appear are minute autotrophic organisms called phytoplankton, e.g., diatoms; green flagellates; single-celled, colonial, or filamentous green algae; as well as blue green algae. They multiply rapidly. Soon a balance is created by the appearance of zooplankton which feeds on ohytoplankton.
    • Submerged stage: The bottom lined by soft mud having organic matter is favorable for the growth of submerged plants such as Hydrilla, Potamogeton, and Najas.
    • Floating stage: Floating leaved anchored plants (e.g., Nymphaea, Nelumbo, and Nuphar) appear where water becomes shallow. These plants have subterranean stems like rhizome and tuber. The plants make the water rich in mineral and organic matter. It becomes suitable for the growth of free floating plants such as Lemna, Spirodela, Wolffia, Azolla, and Eichhornia.
    • Reed swamp stage: Amphibious plants grow when the water body becomes shallow (0.3-1 m). Examples are Phragmites, Typha, Scirpus, and Sagittaria. The plants of swamp stage transpire nice quantities of water.
    • Sedge or marsh meadow stage: The shores built up in reed swamp stage are invaded by Carex (sedge); Cyperus; Juncus; grasses such as Themeda; and herbs such as Campanula, Caltha, and Polygonum. The plants transpire rapidly and add abundant humus.
    • Scrub/woodland stage: The periphery of sedge meadow stage is invaded by some rhizome bear- ing shrubby plants which can tolerate bright sunlight as well as water logged conditions, e.g., Cornus (bogwood), Cephalanthus (button brush); etc. They invite invasion by trees capable of bearing bright sunlight and water logging, e.g., Populus (cottonwood) and Alnus (alder).
    • Climax forest: New trees invade the area. They have shade-loving seed plants. These trees grow to greater heights.

Nutrient Cycling

Nutrient cycling is of three types:

  • Gaseous: Examples are carbon (absorbed as CO2), nitrogen, oxygen (as vapors), and main reservoir pool (as atmosphere or water).
  • Sedimentary: Biogenetic materials are nongaseous and have lithosphere as the main reservoir pool. Examples are P, Ca, and Mg. Both sedimentary and gaseous phases occur in case of sulfur.
  • Mixed: Nutrients have both gaseous and nongaseous states, e.g., sulfur. Tundra consists of plains with snow, ice, and frozen soil (permafrost).

Aquatic Biomes

Five general categories of aquatic ecosystems are usually recognized:

  • Marine pelagic areas within the water mass of oceans with water of high salinity
  • Marine benthic areas on the ocean floor with water of high salinity
  • Estuaries, bodies, or oceanic water near the mouths of freshwater rivers with intermediate salinity
  • Freshwater lotic with flowing water of low salinity Freshwater lentic with non-flowing water of low salinity

Marine Biome

The marine environment is characterized by its high concentration of salt (about 3.5% in open sea) and mineral ions (mostly sodium and chloride followed by sulfur, magnesium, and calcium). All ocean basins are roughly of the shape of a wash basin (or an inverted hat).

From the coastline, a gradually sloping region extends to about 160 km into the sea. This zone, with a depth of 8-200 m, is called the continental shelf. The angle of the slope then abruptly steepens to form the continental slope which levels off into a more or less horizontal expanse forming the ocean floor.

The vertical zones of the ocean are determined on the basis of availability of light for photosynthesis.

  • The well-lit upper 200 m forms the photic or euphotic zone.
  • The next zone up to the depth 200-2000 m gets less light which is insufficient for photosynthesis and forms disphotic zone.
  • Below 2000 m is the area of perpetual darkness-the abyssal zone/dark zone.

Freshwater Biomes (Lakes and Ponds)

Freshwater biomes are stationary water bodies. Ponds are small and shallow. Lakes are larger and deeper. Lakes develop in na- ture due to the following reasons:

  • Glaciation
  • Natural or man-made depressions
  • Oxbow lakes which develop from the main stream of a river

Depending upon productivity, lakes are of three types:

  • Oligotrophic lakes: These lakes are deep with rocky steep sides and with less circulation of nutrients. They have little biota but are rich in green algae. Brackish lakes are oligotrophic and also occur in arid areas, e.g., Sambhar Lake in Rajasthan.
  • Eutrophic lakes: These lakes are rich in biota and have quick circulation of nutrients. These are shallow with abundant blue green algae, e.g., Dal Lake in Kashmir.
  • Dystrophic lakes: These lakes are rich in humic acid and are less productive.

Life Forms

Raunkiaer (1934) has distinguished plants into five forms on the basis of size, shape, branching, crown, life span, and perennation.

  • Phanerophytes: Perennial herbs, shrubs and trees, epiphytes, succulents, lianas, etc., where perennating buds occur at a height of 10 cm or more above the ground level.
  • Chemaephytes: Small plants of cold areas where perennating buds or shoot apices lie at or above the ground level.
  • Hemieryptophytes: Perennating structures occur at the ground level. Aerial shoots die with the onset of winter, e.g., rosette plants.
  • Cryptophytes: Perennial plants with underground storage parts. These are of different types such as
    • Geophytes: These Subterranean perennating structure (root, root tuber, bulb, stem tuber, rhizome, corm).
    • Halophytes (marshy plants): Perennating structure embedded in mud.
    • Hydrophytes (aquatic plants)
    • Thorophytes: Plants which perennate in the form of seeds.

Ecosystem Services

The products of ecosystem processes are called ecosystern services, e.g., healthy forest ecosystems purify air and water, mitigate droughts and floods, cycle nutrients, generate fertile soils, provide wildlife habitat, maintain biodiversity, pollinate crops, provide storage site for carbon, and also provide aesthetic, cultural, and spiritual values.

Researchers like Robert Constanza et. al. have put an average price tag of US$ 33 trillion a year on these fundamental ecological services (i.e., nearly twice the value of a global GNP – US$ 18 trillion).

Out of total cost, soil formation accounts for about 50%, recreation and nutrient cycling less than 10% each, and climate regulation and habitat for wildlife account for about 6% each.

 

Assertion-Reasoning Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).

  1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).
  2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
  3. If Assertion is true but Reason is false, then mark (3).
  4. If both Assertion and Reason are false, then mark (4).

Question 1. Assertion: Agriculture and aquacultures are man-maintained ecosystems.

Reason: All biotic and abiotic factors are managed by humans in these ecosystems.

Answer. 1. In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).

Question 2. Assertion: Warm and moist environment can enhance the rate of decomposition.

Reason: Warm and moist climate leads to create anaerobic condition which promotes decomposition.

Answer. 3. If Assertion is true but Reason is false, then mark (3).

Question 3. Assertion: Detritus food chain begins with decomposers.

Reason: Detrivores, like fungi and bacteria, are major decomposers in such food chains.

Answer. 3. If Assertion is true but Reason is false, then mark (3).

Question 4. Assertion: Ecological pyramids cannot explain all vital functions of any ecosystem.

Reason: Pyramids actually do not explain the role of organisms working at more than one trophic level.

Answer. 2. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

Question 5. Assertion: Successional process starts only in those areas where no living organisms ever existed.

Reason: These areas are not supported by physical environmental conditions.

Answer. 4. If both Assertion and Reason are false, then mark (4)

NEET Biology Multiple Choice Questions – Organisms And Populations

 Organisms And Populations Multiple Choice Questions

Question 1. The term “ecology” was given by

  1. Odum
  2. Haeckel
  3. Tansley
  4. R. Misra

Answer. 2. Haeckel

Question 2. A large regional unit characterized by a specific flora and fauna is called

  1. Biome
  2. Biosphere
  3. Ecosystem
  4. Landscape

Answer. 1. Biome

Question 3. A group of individuals living in a particular geographical area at a particular time is called

  1. Local population
  2. Deme
  3. Community
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 4. The functional role and status of a species in a community is called

  1. Performance
  2. Ecological niche.
  3. Tolerance
  4. Organization

Answer. 2. Ecological niche.

Question 5. Organisms living in arctic and antarctic climatic zones are called

  1. Megatherms
  2. Mesotherms
  3. Microtherms
  4. Hekistotherms

Answer. 4. Hekistotherms

Question 6. The two climatic factors which largely determine the vegetation and soil types are

  1. Temperature and precipitation
  2. Temperature and light
  3. Light and precipitation
  4. Light and weather

Answer. 1. Temperature and precipitation

Question 7. Chylorhizy is found in

  1. Opuntia
  2. Euphorbia
  3. Asparagus
  4. Aloe

Answer. 3. Asparagus

Question 8. The value of lapse rate is

  1. 1.6°C per 100 m elevation
  2. 6.5°C per 100 m elevation
  3. 6.5°C per 1000 m elevation
  4. 6.5°C per 10 m elevation

Answer. 3. 6.5°C per 1000 m elevation

Question 9. Solar constant is _____________ cal cm2/mm.

  1. 2
  2. 4
  3. 6
  4. 8

Answer. 1. 2

Question 10. The most harmful radiation is

  1. UV-A
  2. UV-B
  3. UU-C
  4. All are equally harmful

Answer. 2. UV-B

Question 11. The timing of seasonal activity of plants in relation to environmental conditions is called

  1. Physiognomy
  2. Phenology
  3. Stratification
  4. Agrostology

Answer. 2. Phenology

Question 12. The bottom zone in a lake is called

  1. Limnetic
  2. Profundal
  3. Benthic
  4. Littoral

Answer. 3. Benthic

Question 13. The number of temperature zones in a summer lake is

  1. 2
  2. 3
  3. 4
  4. 5

Answer. 2. 3

Question 14. In meromictic lakes, the number of turnovers of water per year is

  1. 1
  2. 2
  3. Many
  4. Zero

Answer. 4. Zero

Question 15. The turnover in a lake in spring and autumn results in

  1. Free mixing of O, and nutrients
  2. Algal bloom
  3. Temperature inversion
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 16. Shorter body extremities in animals living in colder climate is explained by

  1. Allen’s rule
  2. Bergman’s rule
  3. Gloger’s rule
  4. Jordan’s rule

Answer. 1. Allen’s rule

Question 17. Permanent wilting percentage (PWP) is the highest in

  1. Silt
  2. Sandy soil
  3. Loam
  4. Clay soil

Answer. 2. Sandy soil

Question 18. In soil profile, the zone of eluviation is

  1. O-zone
  2. A-zone
  3. B-zone
  4. C-zone

Answer. 2. A-zone

Question 19. A good soil is that which

  1. Allows little water to enter in it
  2. Allows extra water to percolate slowly
  3. Holds water entering it
  4. Allows water to pass through it quickly

Answer. 2. Allows extra water to percolate slowly

Question 20. The size of clay particles is

  1. Between 0.00002 and 0.02 mm
  2. Less than 0.002 mm
  3. 0.5-1.0 mm
  4. 0.02-0.2 mm

Answer. 2. Less than 0.002 mm

Question 21. Alluvial soils are mostly found in

  1. Northern India
  2. Eastern India
  3. Southern India
  4. Ganges and Yamuna plains

Answer. 4. Ganges and Yamuna plains

Question 22. Which of the following soils shows cracks and shrinks most when it dries?

  1. Porous soil
  2. Clay soil
  3. Loam soil
  4. Sandy soil

Answer. 2. Clay soil

Question 23. Soil porosity is the maximum in

  1. Sandy soil
  2. Clay soil
  3. Silt
  4. Loan

Answer. 2. Clay soil

Question 24. Mull humus is characterized by

  1. Nutrient deficiency
  2. Layered composition
  3. Ca+2 deficiency
  4. Rich bacterial growth

Answer. 4. Rich bacterial growth

Question 25. What is the percentage of air in the soil?

  1. 50
  2. 10
  3. 45
  4. 25

Answer. 4. 25

Question 26. The law of tolerance was given by

  1. Shelford
  2. Haeckel
  3. J. Grinnel
  4. Gause

Answer. 1. Shelford

Question 27. The critical minimum and maximum value of an environmental factor is called

  1. Limiting factor
  2. Law of minimum
  3. Limits of tolerance
  4. Carrying capacity

Answer. 3. Limits of tolerance

Question 28. Weeds are usually

  1. Eurytopic
  2. Stenotopic
  3. Amensal
  4. Smoother crops

Answer. 1. Eurytopic

Question 29. A genotypically adapted local population is called

  1. Ecad
  2. Ecotype
  3. Ecocline
  4. Ecotone

Answer. 2. Ecotype

Question 30. Phreatophytes are/have

  1. True xerophytes
  2. Deep roots
  3. Indicator plants
  4. All of these

Answer. 4. All of these

Question 31. Chemicals which provide physiological adaptations to plants against high temperature and saline conditions are

  1. Chaperonins
  2. Proline, glycerol
  3. Betaine, sorbital
  4. All of these

Answer. 4. All of these

Question 32. Vivipary and prop roots are the characteristics of

  1. Coastal plants
  2. Hot desert plants
  3. Mangrove plants
  4. Cold desert plants

Answer. 3. Mangrove plants

Question 33. Which of the following characters does not characterize a hydrophyte?

  1. Abundant air space and air chambers
  2. Abundant xylem and sclerenchyma
  3. Leaves having stomata only on upper side or none
  4. Poor development of roots

Answer. 2. Abundant xylem and sclerenchyma

Question 34. Plants are killed in the winter by frost

  1. Because of desiccation and mechanical damages to the tissues
  2. Because no photosynthesis takes place at such low temperature
  3. Because respiration ceases at such low temperature
  4. Because there is no transpiration

Answer. 1. Because of desiccation and mechanical damages to the tissues

Question 35. Ephemerals are xeropytes that are

  1. Drought enduring
  2. Drought escaping
  3. Drought resisting
  4. None of these

Answer. 2. Drought escaping

Question 36. The factors which include the form, surface, and behavior of the earth with special reference to slopes, mountains, and valleys are called

  1. Edaphic factors
  2. Biotic factors
  3. Climatic factors
  4. Topographic factors

Answer. 4. Topographic factors

Question 37. The capacity to blend with surroundings is called

  1. Hibernation
  2. Mimicry
  3. Camouflage
  4. Aestivation

Answer. 3. Camouflage

Question 38. A behavioral strategy of adaptation called echolocation is found in

  1. Bats
  2. Monarch butterfly
  3. Praying mantis
  4. Arctic tern

Answer. 1. Bats

Question 39. Natality under actual conditions is called

  1. Biotic potential
  2. Maximum natality
  3. Ecological natality
  4. Reproductive potential

Answer. 3. Ecological natality

Question 40. Vital index of a population is

  1. (B/D) × 100
  2. B-D
  3. (D/B) × 100
  4. B+D

Answer. 1. (B/D) × 100

Question 41. An urn-shaped population-age pyramid represents

  1. Growing population
  2. Static population
  3. Declining population
  4. Threatened population

Answer. 3. Declining population

Question 42. The ability of an environment to support a population is called its

  1. Biotic potential
  2. Purifying capacity
  3. Carrying capacity
  4. Environmental resistance

Answer. 3. Carrying capacity

Question 43. In the equation for S-shaped population growth, r represents

  1. Carrying capacity
  2. Environmental resistance
  3. Biotic potential
  4. Population size

Answer. 3. Biotic potential

Question 44. Which of the following statements is not true for J-shaped growth curve?

  1. Exponential phase is prolonged.
  2. Population never grows beyond carrying capacity.
  3. Population crash occurs.
  4. Population seldom reaches equilibrium.

Answer. 2. Population never grows beyond carrying capacity.

Question 45. In the formula of population growth, rN represents the

  1. Environmental resistance
  2. Reproductive potential
  3. Growth rate
  4. Carrying capacity

Answer. 1. Environmental resistance

Question 46. Which statement is not related to S-shaped population curve?

  1. Environmental resistance suddenly becomes effective.
  2. Exponential phase is followed by decline phase.
  3. Mass mortality and population crash occurs.
  4. Both (1) and (3).

Answer. 4. Both (1) and (3).

Question 47. The periodic departure and return is known as

  1. Migration
  2. Immigration
  3. Emigration
  4. Mutation

Answer. 1. Migration

Question 48. When an animal group is centered around a dominant female, it is called

  1. Patriarchy
  2. Matriarchy
  3. Swarm
  4. Flock

Answer. 2. Matriarchy

Question 49. Altruistic behavior is not found in

  1. White ants
  2. Spotted deer
  3. Honey bees
  4. Bitch

Answer. 4. Bitch

Question 50. Territory is defended against

  1. Predator
  2. Any intruder
  3. Intruder of another species
  4. Intruder of the same species

Answer. 4. Intruder of the same species

Question 51. The inability of different organisms to interbreed is called

  1. Sterility
  2. Parasitism
  3. Reproductive isolation.
  4. Monogamy

Answer. 3. Reproductive isolation.

Question 52. The increased number and density of species in the region of ecotone is called

  1. Edge effect
  2. Sympatric speciation
  3. Dominance
  4. Abundance

Answer. 1. Edge effect

Question 53. Which of the following associations is not an example of symbiosis?

  1. Lichen
  2. Mycorrhiza
  3. Root nodules
  4. Epiphytes

Answer. 4. Epiphytes

Question 54. Which is not an effect of competition?

  1. Regulation of population size
  2. Generalization of niche
  3. Establishment of social hierarchy
  4. Help in speciation

Answer. 2. Generalization of niche

Question 55. Competitive exclusion principle was given by

  1. J. Grinnel
  2. Gause
  3. Lindeman
  4. Bates

Answer. 2. Gause

Question 56. Which of the following shows biological antagonism or allelopathy?

  1. Amensalism
  2. Proto-cooperation
  3. Competition
  4. Parasitism

Answer. 1. Amensalism

Question 57. The interaction between two living organisms of different species which is beneficial to both but is not obligatory because they can live without each other is known as

  1. Proto-cooperation
  2. Mutualism or symbiosis
  3. Commensalism
  4. Amensalism

Answer. 1. Proto-cooperation

Question 58. Find the odd one out:

  1. Lianas in tropical rain forest
  2. E. coli in large intestine of man
  3. Pilot fish remora and shark
  4. Rafflesia on the roots of a forest tree

Answer. 4. Rafflesia on the roots of a forest tree

Question 59. Find the odd one out:

  1. Mating
  2. Competition
  3. Aggregation
  4. Altruism

Answer. 2. Competition

Question 60. A toxic chemical against nematode is secreted by

  1. Tagetes
  2. Black walnut
  3. Penicillium
  4. Grevillea robusta

Answer. 1. Tagetes

Question 61. Which one of the following is a hemiparasite?

  1. Viscum
  2. Cuscuta
  3. Rafflesia
  4. None of these

Answer. 1. Viscum

Question 62. Competition for food, light, and space is most severe between two

  1. Distantly related species growing in different habitats
  2. Distantly related species growing in the same habitat
  3. Closely related species growing in different habitats
  4. Closely related species growing in the same area

Answer. 4. Closely related species growing in the same area

Question 63. The species which are present in large numbers and have large size are called

  1. Ecological equivalent
  2. Ecological dominants
  3. Link species
  4. Keystone species

Answer. 2. Ecological dominants

Question 64. The transition zone between two communities is called

  1. Ecocline
  2. Ecotone
  3. Buffer zone
  4. Thermocline

Answer. 2. Ecotone

Question 65. Which of the following is a keystone species?

  1. Fig
  2. Deer
  3. Mycorrhiza
  4. Pollinator

Answer. 1. Fig

Question 66. Find the odd one out:

  1. Viceroy butterfly resembling monarch butterfly
  2. Stick insect resembling thin, dry branches
  3. Caterpillars of geometrid moth resembling small branches
  4. Leaf insect resembling green leaf

Answer. 1. Viceroy butterfly resembling monarch butterfly

Question 67. Mimicry is a device for

  1. Concealing from predator
  2. Concealing from prey
  3. Both (1) and (2)
  4. Becoming conspicuous

Answer. 3. Both (1) and (2)

Question 68. Match the following columns:

Column 1                                Column 2

a. Oxylophytes                (1) Calcium-rich soils

b. Eremophytes              (2) Waste land

c. Chrysophytes              (3) Deserts, steppes

d. Calciphytes                 (4) Acidic soils

  1. a (1), b (2), c (3), d (4)
  2. a (1), b (3), c (4), d (2)
  3. a (4), b (3), c (2), d (1)
  4. a (4), b (3), c (1), d (2)

Answer. 3. a (4), b (3), c (2), d (1)

Question 69. Which of the following statements is correct?

  1. Two species within a given community can have exactly the same niche.
  2. Two species within a given community cannot have exactly the same niche.
  3. Two species can live permanently together
  4. Both (2) and (3).

Answer. 4. Both (2) and (3).

Question 70. Biotic potential refers to

  1. Increase of population under optimum conditions
  2. Increase of population under given conditions
  3. Increase of population under natural conditions
  4. Increase of population under stress conditions

Answer. 1. Increase of population under optimum conditions

Question 71. Edge effect refers to

  1. Occurrence of ecophenes and ecotypes in a community
  2. Low diversity of organisms in ecotone
  3. High diversity of organisms in ecotone
  4. Defense of territories by organisms

Answer. 3. High diversity of organisms in ecotone

Question 72. In India, tropical rain forests are generally found in

  1. Western Ghats
  2. North-eastern Himalayas
  3. Gangetic Plains in India
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 73. The forests which show contrasting seasonal aspects are

  1. Tropical rain forests
  2. Temperate broad-leaf forests
  3. Tropical deciduous forests
  4. Temperate needle-leaf forests

Answer. 3. Tropical deciduous forests

Question 74. Which is not a characteristic feature of grassland?

  1. Extensive root system
  2. High productivity
  3. Periodic fire
  4. Developed stratification

Answer. 4. Developed stratification

Question 75. Most of the deserts are distributed between

  1. 150-350 latitude
  2. 400-600 latitude
  3. 600-800 latitude
  4. Only in Southern Hemisphere

Answer. 1. 150-350 latitude

Question 76. A biome having a well-developed grass cover interspersed with scattered trees is a

  1. Grassland
  2. Savannah
  3. Desert
  4. Temperate forest

Answer. 2. Savannah

Question 77. The taiga region is also known as

  1. Deciduous forest
  2. Tropical rain forest
  3. Northern conifer forest
  4. Tropical savannah

Answer. 3. Northern conifer forest

Question 78. The grassland vegetation of Africa is known as

  1. Prairies
  2. Pampas
  3. Steppes
  4. Veldts

Answer. 4. Veldts

Question 79. Arctic tundra is

  1. Highest latitudinal biome
  2. Located in rain shadow
  3. Characterized by Capparis and Prosopis species
  4. Highest altitudinal biome

Answer. 1. Highest latitudinal biome

Question 80. Ethology is the study of

  1. Behaviour of animals
  2. Past life of organism
  3. Disease causing pathogens
  4. None of these

Answer. 1. Behaviour of animals

Question 81. Humus is

  1. Dead and decayed organic matter
  2. Living matter
  3. Fertilizers
  4. Living animal/plants/microbes

Answer. 1. Dead and decayed organic matter

Question 82. Name the famous plant ecologist:

  1. Jagdish Chandra Bose
  2. Birbal Shani
  3. Ramdeva Misra
  4. Charles Darwin

Answer. 3. Ramdeva Misra

Question 83. The correct percentage of CO, in atmosphere is

  1. 0.03%
  2. 0.3%
  3. 1%
  4. 1.1%

Answer. 1. 0.03%

Question 84. In aquatic environment, microscopic animals and plants are collectively known as

  1. Commensals
  2. Herbivores
  3. Fauna and Flora
  4. Planktons

Answer. 4. Planktons

Question 85. June 5 is

  1. World Environment Day
  2. Wold AIDS Day
  3. World Womens Day
  4. World Polio Day

Answer. 1. World Environment Day

Question 86. Plants developing in dry condition are

  1. Xerophytes
  2. Mesophytes
  3. Lithophytes
  4. Hydrophytes

Answer. 1.Xerophytes

Question 87. Soil carried by gravity is

  1. Alluvial
  2. Colluvial
  3. Elluvial
  4. Glacial

Answer. 2. Colluvial

Question 88. Velamen tissue is found in

  1. Mesophytes
  2. Epiphytes
  3. Hydrophytes
  4. Xerophytes

Answer. 2. Epiphytes

Question 89. Pneumatophores are characteristic feature of

  1. Hydrilla
  2. Rhizophora
  3. Typha
  4. None of these

Answer. 2. Rhizophora

Question 90. Factors relating to form and behavior of the earth’s surface are called

  1. Edaphic
  2. Topographic
  3. Climatic
  4. Biotic

Answer. 2. Topographic

Question 91. Aerenchyma is helpful in plants by

  1. Providing buoyancy in hydrophytes
  2. Absorption in stilt roots
  3. Giving mechanical strength to plants
  4. Giving flexibility to plants

Answer. 1. Providing buoyancy in hydrophytes

Question 92. Plants growing in saline soil are called

  1. Xerophyte
  2. Hydrophyte
  3. Halophyte
  4. Heliophyte

Answer. 3. Halophyte

Question 93. Which one of the following is a well-developed tissue present in hydrophytes?

  1. Aerenchyma
  2. Collenchyma
  3. Stomata
  4. Root system

Answer. 1. Aerenchyma

Question 94. Penumetophores are found in

  1. Orchid
  2. Piper
  3. Ficus
  4. Rhizophora

Answer. 4. Rhizophora

Question 95. The term “autecology” refers to the study of

  1. Plant community
  2. Individual organism
  3. Environment
  4. Soil form

Answer. 2. Individual organism

Question 96. Autoecology refers to

  1. Plant ecology
  2. Animal ecology
  3. Ecological study of individual species
  4. Ecological study of group of species, which is grown together

Answer. 3. Ecological study of individual species

Question 97. Which part of the pond ecosystem does not get affected by temperature?

  1. Epilimnion
  2. Metalimnion
  3. Hypolimnion
  4. All

Answer. 3. Hypolimnion

Question 98. Root cap is absent in

  1. Mesophytes
  2. Hydrophytes
  3. Epiphytes
  4. Xerophytes

Answer. 2. Hydrophytes

Question 99. Which of the following have sunken stomata?

  1. Nerium
  2. Mangifera
  3. Hydrilla
  4. Zea mays

Answer. 1. Nerium

Question 100. Velamen and spongy tissue are found in

  1. Breathing roots
  2. Parasitic roots
  3. Tuberous roots
  4. Epiphytic roots

Answer. 4. Epiphytic roots

Question 101. Root cap is absent in

  1. Lithophytes
  2. Xerophytes
  3. Hydrophytes
  4. Mesophytes

Answer. 3. Hydrophytes

Question 102. Which of the following is the example of xerophytes?

  1. Brassica
  2. Cuscuta
  3. Capparis
  4. Hydrilla

Answer. 3. Capparis

Question 103. Organisms inhabiting a common environment belong to the same

  1. Species
  2. Genus
  3. Population
  4. Community

Answer. 4. Community

Question 104. Insectivorous plants usually survive in

  1. Water rich soil
  2. N2 deficient soil
  3. N2 rich soil
  4. Sugar deficient medium

Answer. 2. N2 deficient soil

Question 105. A group of two or more than two plants species is called

  1. Plant community
  2. Animal ecosystem
  3. Plant ecosystem
  4. Ecological niche

Answer. 1. Plant community

Question 106. Two vegetations of ecosystem are separated by

  1. Ecotone
  2. Ecoline
  3. Ecosytem
  4. Ecesis

Answer. 1. Ecotone

Question 107. In plant succession, the last community is called

  1. Ecotone
  2. Climax community
  3. Seral community
  4. Ecocystem

Answer. 2. Climax community

Question 108. In which of the following habitats the diurnal temperature of soil surface varies the most?

  1. Forest
  2. Desert
  3. Grassland
  4. Shrub land

Answer. 2. Desert

Question 109. People who have migrated from the planes to an area adjoining Rohtang Pass about 6 months back

  1. Are not physically fit to play games like football
  2. Suffer from altitude sickness with symptoms like nausea, fatigue, etc.
  3. Have the usual RBC count but their hemoglobin has very high binding affinity to O2
  4. Have more RBCs and their hemoglobin has a lower binding affinity to O2

Answer. 4. Have more RBCs and their hemoglobin has a lower binding affinity to O2

Question 110. Sacred groves are especially useful in

  1. Generating environmental awareness
  2. Preventing soil erosion
  3. Year-round flow of water in rivers
  4. Conserving rare and threatened species

Answer. 4. Conserving rare and threatened species

Question 111. The second stage of hydrosere is occupied by plants like

  1. Azolla
  2. Typha
  3. Salix
  4. Vallisneria

Answer. 4. Vallisneria

NEET Biology Notes – Organisms And Populations

Organisms And Populations

Habitat: A specific place (or locality) where an organism usually lives. It is a physical entity comprising the sum total of the abiotic factors to which a species or a group of species is exposed.

Ecological niche (J. Grinnel): It represents the functional role and status of a species in the environment. It represents habitat and trophic level of a species. No two species can have the same niche even if they are found in the same environment

Population: A group of individuals of the same species in a well-defined geographical area which share or compete for similar resources and can potentially interbreed. Their study links ecology to genetics and evolution of a population.

Community: A number of interrelated populations of different species sharing a common environment.

Ecosystem: A functional unit of nature in which living organisms interact with one another and with their surrounding physical environment.

Biosphere: Any part of atmosphere inhabited by organisms.

Ecology deals with the various principles which govern the relationships between organisms and their environment. The term “ecology” was first used by Reiter in 1868. Ernst Haeckel (1886) first correctly defined ecology as the science dealing with reciprocal relationship of organisms and the external world. Warming (1895) employed this science for the study of plants. E.P. Odum (1963) defined it as the “study of structure and function of nature.”

Clarke, Warming, Weaver, Clements, Schimper, Dauben-malre, Raunkiaer, E.P. Odum, and H.T. Odum are some renowned ecologists. Prof. R. Misra is known as the “Father of Ecology in India.” Other famous Indian ecologists include G.S. Puri and S.C. Pandeya. Ecology gives a holistic perspective to biology.

Read and Learn More NEET Biology Notes

Branches Of Ecology

  • Autecology: Ecology of individuals or species, essentially physiological ecology.
  • Synecology: Study of relationships between communities and environment.
  • Genecology: Study of ecological adaptations in relation to genetic variability.
  • Paleoecology: Study of relationship between organisms and environment in the past.
  • Applied ecology: Application of ecological concepts for human welfare.
  • Systems ecology: Interpretation of ecological concepts in terms of mathematical principles.

Organisms And Their Environment

Environment is the sum total of all external factors, substances, and conditions which influence organisms without becoming their constituent part. Environment is usually divided into two parts: physical environment and biotic environment.

Factors such as components, conditions, and forces of environment which have a direct and indirect effect on the form, functioning, behavior, survival, and reproduction of organisms are called environmental factors. These are of two types: abiotic and biotic. Abiotic factors are divisible into three categories: atmospheric, edaphic, and topographic. Atmospheric factors are light, temperature, water, and wind. Edaphic factors are related to soil. Topographic factors are abiotic or physical factors related to slope, altitude, etc., connected with the surface behavior of the earth. Biotic factors are influences produced by living organisms.

Biome (Major Ecosystems)

A biome is a large natural ecosystem which is distinct in its climatic conditions and has its specific group of climax plants and associated animals. Rainfall, temperature range, nature of soil, barriers, latitude, and altitude determine the nature and extent. of biomes.

The major biomes of India are as follows:

  • Tropical rain forests: In India, tropical rain forests are found mainly along Western Ghats and in north-eastern Himalayas. Dipterocarpus and hopea are the most common tree species in Indian rain forests. They show a 30-40 m tall canopy with four-five strata. Woody climbers and epiphytes grow profusely in these forests. The soil of such forests is highly leached and has a low base content. They require a mean annual temperature of 23-27 °C and 2000-3500 mm rainfall.
  • Tropical deciduous forests: They occur in the northern and southern parts of our country in plains and low hilly areas. Sal, teak, and tendu are the common trees of these forests. These forests show a short structure of 10-20 m. During rainy season, the forest is lush green with dense foliage, whereas in summer, the forest is largely leafless. The soil of these forests is rich in nutrients due to less leaching. They require a mean annual temperature of 22-32°C and mean annual rainfall of 900-1600 mm.
  • Desert: In these biomes, vegetation is very sparse due to extreme temperatures and very little rainfall (below 10 cm). Hot deserts are characterized by high rate of evapotranspiration and albedo. In cold deserts, the conditions are physiologically xeric and they exhibit permafrost, while in hot deserts, the conditions are physically xeric. Important trees of Indian desert are Prosopis cineraria, Acacia sp., Salvadora sp., and Tamarix sp. The common succulents are species of Euphorbia and many members of family Cactaceae.

NEET Biology Organisms And Populations Biome distribution with respect to annual temperature and precipitation

  • Coastal biome: Coastal areas are zones of transition between oceanic and terrestrial habitats and, so, are very sensitive. These are detritus-based biomes, where plants have to adapt to salinity and water-logged conditions. Mangroves are the major types along salt marshes or swamps. Mangroves are characterized by the presence of pneumatophores and viviparous seed germination. Common examples are Rhizophora, Sonneratia, Avicennia, and Laguncularia. Besides, Phoenix, Pandanus, and Casuarina are also found commonly in coastal areas.

Major Abiotic Factors

Temperature

Ecologically, it is the most relevant factor as temperature variation affects the enzyme kinetics, basal metabolic activities, and physiological functions of organisms. So, thermal tolerance de- cides to a large extent the geographical distribution of different species.

Stenothermal

Such organisms live in areas where the temperature is uniform throughout the year. These organisms cannot tolerate temperature variation.

Eurythermal

Such organisms can tolerate large changes in temperature. These organisms are classified into four temperature groups on the basis of their occurrence in different climatic zones.

  • Megatherms: High temperature throughout the year as found in tropical zone.
  • Mesotherms: They are adapted to winters and high summer temperature. These organisms live in subtropical zone.
  • Microtherms: They live in temperate areas where the winter temperature is low but the summer temperature is moderate.
  • Hekistotherms: These organisms are adapted to a brief period of summer below 10°C and a long snowy winter period. This condition occurs in arctic or alpine zone.

Some effects of temperature are defined as under:

  • Bergman’s rule: Warm-blooded animals (birds and mammals) have a larger body size in cold climate than in hotter areas..
  • Allen’s rule: Extremities (legs, ears, tail, and mouth) of warm-blooded animals become smaller in colder areas as compared to the animals of warmer areas.
  • Renton’s rule: In a colder climate, birds possess narrow and acuminate wings as compared to broader wings of birds found in warmer areas.
  • Jordan’s rule: As the temperature is lowered, some fishes possess a larger size with a larger number of vertebrae.

Thermoperiodicity

Thermoperiodicity or thermoperiodism is the response of living organisms to regular changes of temperature. It is of two types: diurnal and seasonal.

  • Diurnal thermoperiodicity: It is the response of organisms to daily changes of temperature. Generally, the day-time temperature is higher while the night-time temperature is lower.
  • Seasonal thermoperiodicity: It is the response of organisms to seasonal changes in temperature. Along with photoperiodicity, it controls the growth of plants.

Thermal Stratification in Lakes

The occurrence of different temperatures in different horizontal layers as in a forest or a deep water body is called thermal stratification. A deep-water body, such as a lake, has three temperature strata: epilimnion, metalimnion, and hypolimnion.

  • Eplimnion: It is the upper stratum in the water body. Epilimnion is warmer during summer and cooler during winter.
  • Metalimnion: It is a short transitional zone between epilimnion and hypolimnion. The middle part of metalimnion is called thermocline. It is the area of maximum temperature changes.
  • Hypolimnion: It is the lower stratum of a water body with lesser temperature fluctuations.

Water

Water is an important component of protoplasm, which is a general solvent. Water is also present over more than 71% surface of the earth as oceans, lakes, rivers, ice caps, and glaciers. The seawater has a high percentage of salt content (3.5%). Water present on land is called fresh water. Its salt content is low-less than 0.5%. The salt concentration (measured as salinity in parts per thousand) is less than 5% in inland water, 30-35% in the sea, and more than 100% in some hypersaline lagoons.

The regular movement of water among various regions and components of biosphere, viz., aquatic systems, air, and land, constitutes a water cycle. Water comes over land and water bodies as precipitation or rainfall. The total global rainfall is 4.46 G. Precipitation comes from water vapors present in air. At any time, the atmosphere contains only 0.13 G of water vapors (1 G or geogram

Animals found in coastal water are called neritic and those found in open water are termed as pelagic. Pelagic organisms are plankton (if microscopic), neuston (if macroscopic and found on the surface), and nekton (if actively swimming). Organisms found at the bottom of water bodies are called benthos.

Light

Light has a wide range of spectrum. The electromagnetic spectrum is a complete range of oscillating waves that travel together through space at a speed of 3 x 105 km/s. At 83 km above the surface of the earth, solar radiation carries an energy equivalent to 2 cal/cm2/min. This value is called solar constant.

Shortwave radiations are cosmic rays (with a wavelength less than 10-5 nm), gamma rays (103-105 nm), X-rays (10-1–10-2 nm), and UV rays (100-400 nm).

All shortwave radiations are extremely harmful. Most of them are trapped in ionosphere and mesosphere. UV rays are also harmful.

NEET Biology Organisms And Populations Light

UV-C and half of UV-B radiations are absorbed by the ozone layer of the stratosphere. A large amount of the rest is dissipated by the particles of troposphere; only a small amount reaches the earth.

Light affects photosynthesis, growth, reproduction, movement, stratification, photoperiodism, and phenology in plants, whereas it affects migration, reproduction, development, pigmentation, locomotion, and the period of activity in animals.

Light Zonation of Lakes

  • Littoral zone: It is exposed to wave action and is highly productive.

NEET Biology Organisms And Populations Littoral zone

  • Limnetic zone: It is an open water body.
  • Euphotic zone: This zone receives maximum light above the light compensation point.
  • Disphotic zone: This zone receives diffused light at or below the light compensation point. It is also known as the twilight zone.
  • Profundal (dark, abyssal) zone: It has no light.
  • Benthic zone: It lies at the bottom of the sea.

Soil

Soil Composition

Soil consists of four components: two solid and two nonsolid. The solid components are mineral particles and organic matter. The nonsolid components are air and water. A fifth component of variable nature is soil organisms.

NEET Biology Organisms And Populations Soil Composition

Chief characteristics of soil are studied with the help of a soil profile. The type of soil profile depends upon the climate and vegetation of the area. The smallest three-dimensional volume of the soil required to study the profile is called pedon. Most soils possess three-four horizons and a number of subhorizons. A soil horizon is a horizontal layer approximately parallel to the soil surface that possesses distinctive properties which are unlike the ones present in adjoining regions. In general, a profile consists of O, A, B, C, and R horizons.

  • Weathering: It is the breaking of rocks into fine particles as present on the soil. Weathering occurs by the following methods:
    • Physical weathering: It is caused by alternate heating and cooling, alternate wetting and drying, and action of frost, snow, rain, and wind.
    • Chemical weathering: Oxidation, reduction, carbonation, and solubilization are performed to break the rock.
    • Biological weathering: It is caused by lichens, mosses, and other organisms.
  • Humification: It is addition of organic matter or humus to a weathered rock. Humification is essential to starting biological activity and nutritional cycling. Humus is a dark-colored amorphous substance. It is slightly acidic and colloidal and is a reservoir of nutrients. The main functions of humus are biogeochemical cycling, preventing soil from compaction, helping in the formation of soil crumbs, and improving the aeration and water-holding capacity of the soil. It also makes the soil spongy, therefore, rendering it easy for penetration by roots.
  • Eluviation and illuviation: The two processes bring about transport and deposition of materials in the soil. Eluviation is washing down of materials from the upper strata of soil and helping in enriching the different layers of soil with minerals. Illuviation is deposition of minerals in the lower strata of soil.
  • Mineral matter: It consists of inorganic substances present as particles of different sizes and composition.
    • Gravel: It is made of fine pebbles with a size of 2-10 mm.
    • Sand: It consists of grains of quartz or silicon dioxide (SiO2). Size varies from 0.02-2.0 mm. Sand is chemically inert. It allows quick percolation of rain or irrigation water. Aeration is good.
    • Silt: It is formed of fine grains of quartz. The size is 0.002-0.02 mm. It is chemically inert.
    • Clay: It is made of Al, Fe, and Si. The size is less than 0.002 mm. Clay particles are chemically active and have fine interspaces that can hold abundant water, but aeration is poor.
    • Soil air: It is the air present in macropores with a size between 20 and 50 μm. A good soil should have 25% air by volume. Soil air is required for the respiration of roots and several microorganisms. Soil air is richer in CO2 and poorer in O2.
    • Soil porosity: It is the percentage of interspaces present per unit dry weight of soil. The value of soil porosity is 30% in sandy soil, 45% in loam soil, and 50% in clay soil. There are two types of soil pores: micropores and macropores. Micropores are small sized interspaces having a diameter of 20 μm or less. These hold water by capillarity. Macropores are interspaces with a size of more than 20 μm.
      Residual soils develop in situ. Transported soils are brought from other places through gravity (colluvial), running water (deposited on flood plains and called alluvial), wind (colian or acolian), and glacier (glacial soil).

Soil Types

  • Red soils: These are acidic laterite soils which are deficient in lime, magnesium, phosphorus, and potassium but rich in organic matter, iron, and aluminum. These soils support tea, coffee, rubber, cardamom, areca nut, and paddy plantation.
  • Black soils: Also called black cotton soils, locally known as regular, these soils have dark brown or black color from organic matter, clay/hydrated iron, aluminum silicate, and undifferentiated B-horizon (A-C soil).
  • Terai/Bhabar soils: These soils are mostly colluvial and highly productive.

Soil Texture

There are three main types of soil textures.

  • Sandy soils: These soils contain about 80% or more of sand, the remaining being silt and clay. Sandy soils are porous and loose. Their water-holding capacity is poor and there is little chemical nutrition.
  • Clay soils: These are soils having 40-50% clay, the rest being silt. Sand is little. Clay soils have abundant capillary pores; therefore, their water-holding capacity is high. Inorganic nutrients are available in good quantity. However, aeration is poor.
  • Loam soils: These soils contain 20% clay, 40% sand, and 40% silt. These have good mineral nutrition, aeration, and hydration. Therefore, loam soils are the best for plant growth.

Soil pH

Soil pH determines the type of soil microorganisms, solubility of different minerals, and the type of plants which will grow on it. In alkaline soils (pH above 7), there is reduced availability of Zn, Mn, Cu, and Fe. In acidic soils, there is an abundance of Fe, Mn, and Al but deficiency of Ca, Mg, and K. Certain soils possess excess of salts, especially of Na and Mg. These are called saline soils. Salinity increases with excessive irrigation. Another category of infertile soil is alkali soil.

Topography

Topography, i.e., surface configuration of an area (physical features like hills, plains, or slopes), also influences the distribution of organisms. For example, the center and edge of a pond or a stream, the top side and underside of a rock, and the north and south face of a ridge or a mountain are usually inhabited by different species of organisms,

Response To Abiotic Factors

A change in one environmental factor leads to change in others also. In other words, all factors are integrated. An organism would have evolved various mechanisms to maintain its internal environment at homeostasis to perform its physiological and biochemical functions. This constancy is necessary for its overall fitness or maximum performance. This may be maintained naturally or artificially.

NEET Biology Organisms And Populations Diagrammatic representation of organismic response

  • Regulate: All birds and mammals and a few lower vertebrates and invertebrates maintain homeostasis by physiological or behavioral means such as thermoregulation and osmoregulation. But plants do not have such mechanisms to regulate homeostasis. The evolutionary success of mammals is believed largely due to this ability.
  • Conform: When organisms cannot maintain thermal and osmotic balance with their environment, they adopt this mechanism, e.g., approximately 99% plants and animals. Thermoregulation is energetically expensive, especially for small animals having large surface area relative to their volume. Due to this, very small animals are rare in polar regions. Some species have the ability to regulate up to a limited range beyond which they become conform (partial regulators).
    For localized or short outburst of stressful conditions, organisms show migration or suspended growth.
  • Migrate: It is the temporary movement of organisms from a stressful area to a more favorable one in terms of food, shelter, spawning, or climate. For example, Siberian cranes migrate from Siberia to Keoladeo National Park, also known as Bharatpur Bird Sanctuary, in Rajasthan. Locums migrate for food and salmon fish migrates for spawning. Similarly, ungulate’s migration in Africa takes place for food.
  • Suspend: It is a stage in the life cycle of organisms where they change their developmental/physiological structural/biochemical behavior to pass through unfavorable conditions. Examples are thick-walled spores in bacteria, fungi, and lower plants; dormancy in seeds and other vegetative parts in higher plants; and hibernation (winter sleep) among organisms which are un- able to migrate, e.g., bears.
  • Aestivation: It is the metabolic inactivity of organisms during hot desiccating summer, e.g., snails and fish.
  • Diapause: It is the stage of temporary suspension of development under unfavorable conditions, e.g., zoo- plankton in lakes and ponds.

Adaptation

Adaptation is an attribute of an organism that enables it to survive and reproduce in its habitat. Adaptations may be morphological, physiological, or behavioral. These are either fixed genetically or remain epigenetic.

Some examples of adaptation are as follows:

  • The kangaroo rat of North American desert fulfills its water demands by internal oxidation of fats. It also has the ability to concentrate its urine.
  • Mammals from a colder climate generally have shorter ears and limbs to minimize heat loss. Here, Allen’s rule is at work.
  • Seals have a thick layer of fat (blubber) below the skin to reduce loss of body heat.
  • Altitude sickness can be expressed at high altitudes where body does not get enough oxygen due to low atmospheric pressure, causing nausea, fatigue, and heart palpitations. Under these conditions, the body increases RBC production, decreases the binding capacity of fibrils, and increases breathing rate. These physiological adaptations allow organisms to respond quickly to stressful conditions.
  • Archaebacteria can flourish at a temperature exceeding 100°C, while humans can perform metabolism in a narrow range (37°C).
  • Antarctic fishes can survive below 0°C, and a variety of invertebrates and fishes are adapted biochemically to survive great depths with crushing pressure.
  • Desert lizards lack the physiological ability to cope with extreme temperatures, but manage the body temperature by behavioral means.

Water-Based Adaptations

On the basis of dependence of plants on water and their relationship with water, Warming (1909) recognized three kinds of plant communities: hydrophytes, xerophytes, and mesophytes.

Hydrophytes: They live in abundance of water with at least their lower parts (roots) and leaves submerged.

Roots of hydrophytes are poorly developed/completely absent in Wolffia, Ceratophyllum, etc.

  • Stems in hydrophytes are of three kinds:Reduced in free floating plants (e.g., Pistia).
  • Narrow and slender in submerged, suspended plants (e.g., Hydrilla and Ceratophyllum).
  • Well-developed in amphibious plants and rhizome growing through the mud (e.g., Nymphaea and Typha).

Leaves in hydrophytes are of the following kinds:

  • Usually long ribbon-like (e.g., Potamogeton) or finely divided (e.g., Ranunculus).
  • In some hydrophytes, leaves of different forms are produced by the same plant-aerial leaves are not dissected but submerged ones are dissected (e.g., Ra-nunculus aquatilis and Limnophila. This is known as heterophylly.
  • Petioles become long, swollen, and spongy (e.g., Nymphaea, Nelumbo, and Saggitaria).

Hydrophytes show the following anatomical adaptations:

  • There is no cuticle over the epidermis.
  • Stomata either are absent or are dysfunctional.
  • Aerenchyma is well developed.
  • Epidermal cells contain chloroplasts.
  • Mechanical tissues such as sclerenchyma and collenchyma are poorly developed.
  • Vascular tissues are poorly developed,
  • Secondary growth is absent.
  • Vegetative propagation is common by runners (e.g., Marsilea), offsets (e.g., Pistia and Eichhornia), rhizomes (e.g., Typha), and turions (fleshy buds, e.g., Potamogeton).
  • Xerophytes: These plants show anatomical and physiological adaptations.Anatomical adaptations: Thick-walled epidermal cells, multiple epidermis (e.g., Nerium), thick cuticle, hypodermis sclerenchymatous, stomata sunken and covered by hair (e.g., Nerium, Casuarina, and Ephedra), water storing parenchyma well developed, conducting and mechanical tissues well developed, palisade multilayered, and cells of succulents contain abundant mucilage.
  • Physiological adaptations: Reduction of transpiration, high osmotic potential, and resistance to desiccation of mucilage to hold water.

On the basis of the nature of soil and causes of unavailability of water, xerophytes are divided into the following categories:

  • Physical xerophytes: These plants grow in soils. which are physically dry (due to shortage of water), e.g., Opuntia, Casuarina, Ruscus, Muehlenbeckia (Coccoloba), etc.
  • Physiological xerophytes: These plants grow in soils having sufficient water which is not available due to high salt concentration (salinity) or very low temperature.

On the basis of life cycle and water storage, xerophytes are divided into the following categories:

  • Ephemerals: These plants are short-living, i.e., have a brief lifespan (6-8 weeks). These evade dry season by disappearing, leaving behind their seeds. Hence, these plants are not true xerophytes, rather drought evaders and drought escapers, e.g., Cassia tora and Tribulus.
  • Succulents (fleshy xerophytes): These plants absorb a large quantity of water during rainy season and store it in different body parts. These suffer only externally. Hence, these are drought avoiding or drought-resistant xerophytes. These are further divided into the following:
    • Stem succulents: e.g., Opuntia, Euphorbia antiquorum, E. splendens, E. tirucolli, and Cereus.
    • Leaf succulents: e.g., Aloe, Agave, Begonia, and Bryopnyiium.
    • Root succulents: e.g., Asparagus and Hebe parviflora.
  • Nonsucculents: These plants are drought endurers and true xerophytes, and can withstand long drought periods (perennial nonsucculents), e.g., Casuartna, Zizyphus, Nenrium, Calotropis, Acacia, and Capparis.

Halophytes: Halophytes are special types of xerophytic plants which grow in saline soils with high concentrations of salts such as NaCl, MgCl2, and MgSO (hence, physiologically dry soil). Halophytic communities growing on swamps are called halophytes.

Population

Population is of two types. One is called deme, which stands for local population living in a specific area. The other is meta population, which consists of the whole set of local populations connected by dispersing individuals.

For the purpose of ecological studies, a group of individuals resulting from asexual reproduction is also considered population.

Population Attributes/Group Attributes

Some characteristics are unique to the group and are not the characteristics of the individuals forming it; for example, an organism is born and dies, and has a specific age, but it does not have birth rate, death rate, and age ratio.

Population characteristics can be best expressed by statistical methods. Some important characteristics are discussed next.

Population Density

Density is the number of individuals per unit area; e.g., millions of Spirogyra filaments in a pond or 200 Parthenium plants in an area. This can also be expressed as “the population biomass per unit area or volume” when we have to count a large number of organisms or find out the role of a single huge banyan tree in an area.

Relative density is a good measure of finding out the total density of fishes in a lake by counting the number of fishes caught per trap. Another example of measuring the size of a population is tiger census in India. This census is based on pug marks and fecal pellets which are used to indirectly estimate the population size of tigers.

Age Ratio Pyramids

An age pyramid is a graphic representation of the proportion of various age groups in a population. There are three types of age pyramids: triangular, bell-shaped, and urn-shaped.

Triangular pyramid: It is the graphic representation of a young or growing population and has a very high proportion of pre-reproductive individuals.

Bell-shaped pyramid: The pyramid is bell-like with pre-reproductive individuals only marginally more than the reproductive individuals. The population is mature or stable.

Urn-shaped pyramid: It has a small number of pre-reproductive individuals, a larger number of reproductive individuals, and a small number of post- reproductive individuals. Such a population shows negative growth.

NEET Biology Organisms And Populations Representation of age pyramids for human population

Population Growth

Some attributes of population are used to estimate its growth as population size may fluctuate in a given habitat in a given period due to changes in the four basic processes discussed as under.

  • Natality: It is the birth rate (an inherent ability of a population to increase) and refers to the number of births in the population during a given period that are added to its initial density.
    The per individual change in a population due to natal- ity can be estimated using AN/Nat,
    where AN, is the number of new individuals produced, Nis the initial population, and At is the change in time.
  • Mortality: It is the death rate (the number of individual dying in a population in a given period).
  • Immigration: It is one-way permanent inward movement of individuals of the same species into a habitat with existing population. This may help to speed up the growth or prevent extinction of a smaller population. In plants, it is a settlement of disseminules.
  • Emigration: It is one-way permanent outward movement of a number of individuals from a population to other habitat area, hence, reducing the size of that local population. Plants are fixed and, so, do not show emigration.

By these population characteristics, the density of a population (M) at time t can be expressed after a period of time t+1 as

N(+1) = N; + [(B + 1) − (D + E)]

where B is the number of births, I is the number of immigrants, D is the number of deaths, and E is the number of emigrants.

NEET Biology Organisms And Populations Schematic of population growth

So, it can be concluded that births and deaths are the most important factors influencing population density.

Growth Models

Biotic potential and environmental resistance: Biotic potential (r) is the maximum or potential natality. The sum of environmen- tal factors that limits the population size is called environmental resistance. Environmental resistance rises with the rise in popula- tion size. The influence of environmental resistance over biotic potential is denoted by (K – N)/N.

Carrying capacity (K): The maximum number of individuals of a population which can be supported with optimum resources for their survival is called the carrying capacity of the environment. The growth of a population depends on its biotic potential, death rate, and birth rate. Depending upon the amplitude of these three, a population may show exponential growth and logistic growth.

  • Exponential growth: Darwin believed a population grows geometrically when the resources are unlimited, as each species realizes its inherent potential to grow. This intrinsic rate of natural increase is called r. The value of r is an important parameter to assess the impact of environmental factors on population growth.
    • Any increase or decrease in a population N during time t (dNidt) will be dN/dt = (b-d) x N, where b is the per capita birth rate and d is the per capita death rate. If (bd) = r, then, dN/dt = rN.
    • The magnitude of r was 0.0205 for human population in India, while it reached 0.0176 in 2001. For Norway rat, it is 0.015 and for flour beetles, it is 0.12.
    • Equation dN/dt = rN describes geometric growth resulting in a J-shaped curve. Such population stops abruptly due to environmental resistance, which suddenly becomes effective, or depletion of a resource. Decline in a J-shaped population is density-triggered, e.g, algal blooms insect population.

NEET Biology Organisms And Populations Population growth curve

  • Logistic growth: This growth form is characterized by a function of carrying capacity (K) for a given population, giving it a more realistic form. Such forms are represented under limited resource conditions, where a population finally reaches an asymptote. This growth form can be described as the Verhulst-Pearl logistic growth and is expressed as
    dN/dt = rN(K-N/K)

    • Life history variation: Any variation in life history is evolved in relation to the selection pressure imposed by environmental factors in order to achieve the most efficient reproductive strategy such as the following:
      • A small number of large-sized individuals are produced (e.g., mammals and birds).
      • A larger number of small-sized individuals are produced (e.g., oysters and fishes).
      • Some organisms breed once in their life time (e.g., Bambusa and Pacific salmon).
      • Some organisms breed many times during their life-time (e.g., mammals and many birds).

Population Interactions

Many populations of different species may require a similar set of environmental gradient where they live and interact with each other and environment in order to survive and perform their activities. These interactions may be assigned “+,” “_” or “0,” where “+” is beneficial, “-” is detrimental, and “0” is neutral.

  • Negative interactions: These are interactions between two species where one species affects others’ growth and survival.
  • Competition: It is a process in which the fitness (r) of one species is significantly lower in the presence of other species.
    • Competition affects plants and herbivores more than carnivores.
    • This may occur between totally unrelated species when they compete for the same resource, e.g., competition for zooplankton between visiting flamingoes and resident fishes in South American lakes.
    • Resources need not be limiting for competition to occur; the feeding efficiency of one species might be reduced due to the inhibitory or interfering presence of other species.

According to Gause’s competitive exclusion principle, two closely related species competing for the same resources cannot coexist indefinitely and the competitively inferior species will be eventually eliminated. Gause performed his experiments on two species of Paramecium: P. aurelia and P. caudatum.

Coexistence: Species facing competition might evolve a mechanism to live in the same niche by changing the feeding time or foraging patterns. This is called resource partitioning. For example, five closely related species of warblers avoid competition by changing their foraging pattern..

Habitat diversification can also reduce competition, e.g., Tribolium and Oryzaephilus. Tribolium Trifolium model best explains both exclusion and coexistence. There are some circumstantial evidences which support the exclusion of species due to competition. For example,

  • Introduction of goats resulted in the exclusion of Abingdon tortoise from Galapagos Islands.
  • The same interaction occurs between Balanus and Chthamalus on the rocky coasts of Scotland.

Competitive release: There occurs a dramatic increase in the population of a less distributed species in a geographical area when its superior competitor is removed experimentally from that area.

Predation: It is an interaction between species involving killing and consumption of prey.

Predation plays the following roles:

  • Transfer of energy (in ecological sense, herbivores are not very different from predators).
  • Keeping prey population under control.
  • The rabbit population in Australia increased tremendously because the land does not have its natural predators. The introduction of prickly pear cactus (Opuntia) in Australia was controlled only after the introduction of its natural predator moth (Cactoblastis cactorum). Similarly, red foxes in New Zealand have become top carnivores due to the absence of a natural carnivore.
  • Predators help maintain species diversity in a community as they can reduce the intensity of competition among prey species; e.g., experimental removal of Pisaster (star fish) resulted in the extinction of more than ten species of invertebrates.
  • According to the Slobodkin’s principle of prudent predator, a predator does not exterminate its prey by overexploitation.

For their defense, prey species have evolved various adaptations, which are listed as follows:

NEET Biology Organisms And Populations Predation

  • Monarch butterfly is well known for its general unpalatability to its predator birds. This insect is able to sequester highly toxic glycosides present in milkweeds on which its caterpillar stages feed. There larvae develop on milkweed providing the protection to plant against herbivory.
  • Cardiac glycosides are produced by Calotropis. Nicotine, caffeine, quinine, and strychnine are other means of chemical defense in plants.
  • The association of bullhorn Acacia cornigera with Pseudomyrmex ferruginea (acacia ant) is a defense against herbivory. This is also an example of coevolution.

Parasitism: This also depresses the growth rate of a population or may reduce the total size of the population. Parasites are generally smaller. Majority of them are host-specific. A high reproductive potential, loss of digestive system and unnecessary sense organs, and the presence of specific sucking or adhesive organs are some of their characteristics, but they have poor means of dispersal.

Various types of parasites are given as follows:

  • Ectoparasites: Examples are lice on humans, ticks on dogs, copepods on marine fishes, and Cascuta on hedge plants.
  • Endoparasites: These are extremely specialized parasites, with a complex life cycle but simplified morphologically and anatomically. Examples are liver fluke, plasmodium, etc.
  • Brood parasitism: An example of this type of parasitism is cuckoo which lays its eggs in a crow’s nest.
  • Hyperparasites: Examples are bacteriophages, which are parasite over parasitic bacteria. Similarly, Pasteurella pestis is a parasite of rat flea, which is a rat parasite.
  • Amensalism (-, 0): It is both a detrimental and a neutral relationship, where chemical secretion by one organism inhibits the growth of the other. Examples are allelopathic plants such as Prosopis juliflora and black walnut.

Positive interactions: It is an association between two species where one or both populations realize positive effects. This is necessary to achieve homeostasis.

Commensalism (+, 0): It is the simplest form of interaction, in which one species is benefitted while the other is neither harmed nor benefitted. Examples are orchid epiphytes on mango trees, cattle egret and grazing cattle, barnacles growing on the back of a whale, clown fish and sea anemone, and pilot and sucker fish with shark.

Mutualism (+, +): It is an obligatory relation where both species are benefitted. It is essential for their survival on the earth. Examples are mutualistic N2-fixing relation, lichens, mycorrhiza, termite-intestinal flagellate relation, and plant-pollinator relation. Sometimes, it is a one-to-one coevolution- ary relation such as fig and wasp relation, Ophrys and Colpa relation, and Yucca and Pronuba relation.

Some insects such as queens of Bombus affinis cheat plants to steal nectar from the spurs of Aquilegia.

Proto-cooperation (+, +): It is a nonobligatory relation where organisms of both species are benefitted. Examples are oxpecker and rhinoceros, and plover bird and crocodile.

 

Assertion-Reasoning Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).

  1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).
  2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
  3. If Assertion is true but Reason is false, then mark (3).
  4. If both Assertion and Reason are false, then mark (4).

Question 1. Assertion: Holistic approach explains the environmental interactions.

Reason: All environmental factors are integrated with no limits of time and space.

Answer. 3. If Assertion is true but Reason is false, then mark (3)

Question 2. Assertion: Some organisms can maintain internal homeostasis by means of physiological processes and are called “regulates.”

Reason: Regulates can maintain internal homeostasis only up to a limit under stressful conditions.

Answer. 3. If Assertion is true but Reason is false, then mark (3)

Question 3. Assertion: Population ecology is a link of ecology to population genetics and evolution.

Reason: Natural selection operates at population level to evolve the desired traits.

Answer. 1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

Question 4. Assertion: Under unlimited resource conditions, a population can show an exponential growth curve.

Reason: The maximum possible number of individuals can always be supported when enough resources are available.

Answer. 2. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion, then mark

Question 5. Assertion: Insects contribute the maximum to the total diversity of animals.

Reason: Angiosperms and insects are coevolved to perform as plant-pollinator.

Answer. 1. If both Assertion and Reason are true and the reason is the correct explanation of the assertion, then mark (1).

NEET Biology Multiple Choice Questions – Bio Technology And Its Applications

Bio Technology And Its Applications

Question 1. Which one of the following can be used as a permanent cure for ADA deficiency?

  1. Bone marrow transplantation on detection of disorder in adults.
  2. Enzyme replacement therapy at any point in life.
  3. Both (1) and (2).
  4. Gene therapy at early embryonic stages.

Answer. 4. Gene therapy at early embryonic stages.

Question 2. Which one of the following is a transgenic product useful for the treatment of hemophilia?

  1. Factor VIII
  2. Antithrombin II
  3. α-1-antitrypsin
  4. Lysostaphin

Answer. 1. Factor VIII

Question 3. Who is responsible for obtaining interferons through re- combinant DNA technique?

  1. A.R. Bounting
  2. Eli Lily
  3. Charles Weissmann
  4. A. Tiselius

Answer. 3. Charles Weissmann

Question 4. Select the incorrect statement:

  1. RNAi silencing takes place in all eukaryotic organ- isms as a method of cellular defense.
  2. RNAi requires silencing of mRNA by binding of complementary ssDNA molecule.
  3. Complementary nucleic acid could be from mobile genetic elements (transposons).
  4. Ti plasmid with nematode-specific genes has been used in RNAi.

Answer. 2. RNAi requires silencing of mRNA by binding of complementary ssDNA molecule.

Question 5. Which gene controls the transcription of chain A and chain B required for humulin synthesis in E. coli?

  1. B-Lactamase
  2. B-Galactosidase
  3. Polygalacturonase
  4. Chitinase

Answer. 2. B-Galactosidase

Question 6. Transgenic Brassica napus has been used for the synthesis of

  1. Hirudin
  2. Heparin
  3. Polygalacturonase
  4. Cry protein

Answer. 1. Hirudin

Question 7. Which genes encode the protein to control bollworm infection in cotton plants?

  1. Cry II Ab
  2. Cry I Ac
  3. Both (1) and (2)
  4. Amp

Answer. 3. Both (1) and (2)

Question 8. Which is incorrect with respect to GM food?

  1. It contains the protein produced by the transgene in question.
  2. GM food contains antibiotic resistance gene itself.
  3. The enzyme produced by antibiotic resistance gene will not cause allergies.
  4. The bacteria in gut of humans could take by antibiotic resistance gene.

Answer. 3. The enzyme produced by antibiotic resistance gene will not cause allergies.

Question 9. Golden rice-a transgenic variety of rice is principally richer than normal rice in

  1. Cry I Ab
  2. Hirudin
  3. TPA
  4. B-carotene

Answer. 4. B-carotene

Question 10. Southern blotting cannot be performed without

  1. Restriction endonucleases
  2. Agarose
  3. Monoclonal antibodies
  4. Both (1) and (2)

Answer. 4. Both (1) and (2)

Question 11. Plants, bacteria, fungi, and animals whose genes have been altered by manipulation are called genetically modified organisms (GMO). Which of the following statement is not applicable to GM plants?

  1. Reduced reliance on chemical pesticides.
  2. Prevent early exhaustion of fertility of soil.
  3. Crops less tolerant to abiotic stress (cold, drought, salt, and heat).
  4. Enhanced nutritional value of food.

Answer. 3. Crops less tolerant to abiotic stress (cold, drought, salt, and heat).

Question 12. In case of Bacillus thuringiensis, Bacillus itself is not killed by toxic protein crystals produced by it because

  1. Bt toxin protein is not produced in Bacillus
  2. Bt toxin protein is produced in very less amount in Bacillus
  3. Bt toxin exists as inactive toxin
  4. Bt toxin cannot cause any damage to Bacillus

Answer. 3. Bt toxin exists as inactive toxin

Question 13. Bt toxin kills the insect by

  1. Blocking nerve conduction
  2. Damaging the surface of trachea
  3. Creating pores in the tracheal system
  4. Creating pores in the mid gut

Answer. 4. Creating pores in the mid gut

Question 14. Which of the following cry gene codes for the protein which can control the corn borer effectively?

  1. cry I Ac
  2. cry II Ab
  3. cry I Ab
  4. cry II Ac

Answer. 3. cry I Ab

Question 15. RNA interference (RNAi) technique has been devised to protect plants from nematode. In this technique, the mRNA of nematode is silenced by _______ produced by the host plant.

  1. dsDNA
  2. ssDNA
  3. dsRNA
  4. Target proteins

Answer. 3. dsRNA

Question 16. Which of the following peptide chain is removed during the maturation of pro-insulin into insulin?

  1. A peptide
  2. B peptide
  3. C peptide
  4. A and C peptides

Answer. 3. C peptide

Question 17. Eli Lilly, an American company, prepared two DNA se- quences corresponding to A and B chains of human insulin and introduced them in the plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted, and combined by creating

  1. Peptide bonds
  2. Ionic bonds
  3. H-bonds
  4. Disulfide bonds

Answer. 4. Disulfide bonds

Question 18. The first clinical gene therapy was given in 1990 to a 4-year old girl with which of the following enzyme deficiency?

  1. Adenosine deaminase
  2. Tyrosine oxidase
  3. Monamine oxidase
  4. Glutamate dehydrogenase

Answer. 1. Adenosine deaminase

Question 19. Which of the following could be a permanent cure for the treatment of severe combined immunodeficiency (SCID)?

  1. Bone marrow transplantation
  2. Enzyme replacement therapy
  3. Both (1) and (2)
  4. Gene therapy

Answer. 4. Gene therapy

Question 20. Which of the following technique is being used to detect mutations in genes in suspected cancer patients?

  1. PCR
  2. ELISA
  3. Blood analysis
  4. PAGE

Answer. 1. PCR

Question 21. Animals that have had their DNA manipulated to possess and express an extra gene are known as

  1. Foreign animals
  2. Superior animals
  3. Transgenic animals
  4. Intergenic animals

Answer. 3. Transgenic animals

Question 22. About 95% of all existing transgenic animals are

  1. Rabbits
  2. Pigs
  3. Cows
  4. Mice

Answer. 4. Mice

Question 23. Today, transgenic models exist for many human diseases which includes

A. Cancer

B. Cystic fibrosis

C. Rheumatoid arthritis

D. Alzheimer’s disease

  1. (A) and (C) only
  2. (B) and (C) only
  3. (A), (B), and (C) only
  4. All of these

Answer. 4. All of these

Question 24. Which of the following is not a true statement with respect to Bt cotton?

  1. Bt toxin is produced by a bacterium Bacillus thuringiensis.
  2. It is an example of biopesticide.
  3. Bt toxin gene has been cloned in plants to provide resistance to insects.
  4. Bt cotton could decrease the amount of pesticide used.

Answer. 3. Bt toxin gene has been cloned in plants to provide resistance to insects.

Question 25. How many recombinant therapeutics have been approved for human use all over the world?

  1. 12
  2. 30
  3. 20
  4. 18

Answer. 2. 30

Question 26. Which of the following techniques serve the purpose of early diagnosis?

A. Recombinant DNA technology

B. PCR

C. ELISA

  1. (A) only
  2. (A) and (C) only
  3. (A) and (B) only
  4. All of these

Answer. 4. All of these

Question 27. Which of the following technique is based upon the principle of antigen-antibody interaction?

  1. PCR
  2. ELISA
  3. Recombinant DNA technology
  4. RNA interference

Answer. 2. ELISA

Question 28. Which of the following transgenic protein product has been used to treat emphysema?

  1. α-l-Antitrypsin
  2. α-Lactalbumin
  3. Cry protein
  4. C-peptide

Answer. 1. α-l-Antitrypsin

Question 29. How many varieties of rice have been estimated to be present in India?

  1. 2000
  2. 20,000
  3. 2,00,000
  4. 20,00,000

Answer. 3. 2,00,000

Question 30. The use of bioresources by multinational companies and other organizations without proper authorization from the countries and people concerned without compensatory payment is called

  1. Bioethics
  2. Biopiracy
  3. Bioterror
  4. Bioweapon

Answer. 2. Biopiracy

Question 31. Amongst the following, which characteristic is not applicable to Bt cotton?

  1. Bt is the abbreviated term for botulinum toxin.
  2. Such cotton is resistant to armyworms and beetles.
  3. The toxin is activated in the body of the insect.
  4. The toxin is coded by a gene called “cry.”

Answer. 1. Bt is the abbreviated term for botulinum toxin.

Question 32. Which biotechnology company is credited with the synthesis of genetically engineered human insulin for the first time?

  1. Celera genomics
  2. Cipla
  3. Eli Lily
  4. Ranbaxy

Answer. 3. Eli Lily

Question 33. Functional ADA cDNA can be introduced into the cells of the patient receiving gene therapy by using a vector constituted by

  1. E. coli
  2. Reovirus
  3. Retrovirus
  4. Agrobacterium

Answer. 3. Retrovirus

Question 34. Which variety of rice was patented by a US company even though the highest number of varieties of this rice is found in India?

  1. Shamati Sonara
  2. Co-667
  3. Basmati
  4. Lerma Roja

Answer. 3. Basmati

Question 35. Which step has the Government of India taken to cater to the requirement of patent terms and other emergency provisions in this regard?

  1. Biopiracy Act
  2. Indian Patents Bill
  3. RTI Act
  4. Negotiable Instruments Act

Answer. 2. Indian Patents Bill

Question 36. What is another term used for GMO (genetically modified organisms)?

  1. Cybrid organisms
  2. Genomorphic organisms
  3. Transgenic organisms
  4. Conjoint twins

Answer. 3. Transgenic organisms

Question 37. Transgenic models can be used to investigate several human diseases such as

  1. Alzheimer’s disease
  2. Cystic fibrosis
  3. Carcinoma
  4. All of these

Answer. 4. All of these

Question 38. Which GMO is now being developed in order to be used in testing the safety of polio vaccines before they are used in humans?

  1. Transgenic sheep
  2. Transgenic cow
  3. Transgenic mice
  4. Transgenic viruses

Answer. 3. Transgenic mice

Question 39. Which method of cellular defense is common in all eukaryotic organisms?

  1. RNA interference
  2. Reverse transcription
  3. VNTR
  4. Phagocytosis

Answer. 1. RNA interference

Question 40. “Silencing” of mRNA molecule in order to control the production of a harmful protein has been used in the protection of plants from

  1. Nematodes
  2. Beetles
  3. Mosquitoes
  4. Flies

Answer. 1. Nematodes

Question 41. Mark the odd one with respect to the advantages of genetically modified plants:

  1. Production of food with better nutritional value.
  2. Decrease in post harvest losses.
  3. Decreased dependence on fertilizers.
  4. Decreased usage of minerals.

Answer. 4. Decreased usage of minerals.

Question 42. In which disease has the advancement of genetic engineering still not been used as clinical cure?

  1. Emphysema
  2. Cystic fibrosis
  3. Phenylketonuria
  4. Anencephaly

Answer. 4. Anencephaly

Question 43. Which substance is tested in case of toxicity/safety testing using transgenic animals?

  1. Chemicals
  2. Pathogen
  3. The amount of DNA in the cell
  4. The amount of tolerable radiation levels of an organism

Answer. 1. Chemicals

Question 44. Which step proved to be the main challenging obstacle in the production of human insulin by genetic engineering?

  1. Removal of C-peptide from active insulin.
  2. Getting insulin assembled into a mature form.
  3. Addition of C-peptide to pro-insulin.
  4. Splitting A and B polypeptide chains.

Answer. 2. Getting insulin assembled into a mature form.

Question 45. What is the disadvantage of using processed insulin (from pig pancreas) in diabetic patients?

  1. It leads to hypercalcaemia.
  2. It may cause allergic reactions.
  3. It is expensive.
  4. It can lead to mutations in human recipients.

Answer. 2. It may cause allergic reactions.

Question 46. Why are repeated transfusions of genetically engineered cells required in SCID patients?

  1. The transfused cells have limited lifespan.
  2. The introduced gene is mutated.
  3. The enzyme required is degraded after 20 days of transfusion.
  4. Both (2) and (3).

Answer. 1. The transfused cells have limited lifespan.

Question 47. Which Indian plants have either been patented or attempts have been made to patent them by the Western nations for their commercial use?

  1. Basmati rice
  2. Turmeric
  3. Neem
  4. All of these have been targeted

Answer. 4. All of these have been targeted

Question 48. Why is insulin usually not administered orally to a diabetic patient?

  1. Insulin is bitter in taste.
  2. Insulin is a peptide.
  3. Insulin will lead to a sudden decrease in blood sugar if given orally.
  4. Insulin leads to peptic ulcer orally.

Answer. 2. Insulin is a peptide.

Question 49. Which technique would you expect to be completely curative in SCID?

  1. Gene therapy in adult stage.
  2. Gene therapy in embryonic stage.
  3. Bone marrow transplantation.
  4. Enzyme replacement therapy.

Answer. 2. Gene therapy in embryonic stage.

Question 50. A doctor while operating on an HIV+ patient accidentally cut himself with a scalpel. He comes to you, suspecting himself to have contracted the virus. Which test will you advise him to rule out/confirm his suspicion?

  1. PCR
  2. Routine urine examination
  3. TLC
  4. DLC

Answer. 1. PCR

Question 51. Match the following genes in column 1 with the insects that can be protected from with their coded proteins in column 2.

Column 1                    Column 2

a. cry I Ac                   (1) Cotton bollworm

b.cry I Ab                  (2) Beetles

c. Bt toxin gene        (3) Corn borer

  1. a (1), b (3), c (2)
  2. a (2), b (1), c (3)
  3. a (1), b (2), c (3)
  4. a (2), b (3), c (1)

Answer. 1. a (1), b (3), c (2)

Question 52. Which protein would you like to be produced by genetic engineering as cure for diseases such as emphysema?

  1. α-1-Antitrypsin
  2. Trypsin
  3. Chymotrypsin
  4. All of the above are required

Answer. 1. α-1-Antitrypsin

Question 53. “Rosie,” a transgenic cow, is known to produce a type of milk which has all the following characteristics, except

  1. Protein content of 2.4 g/L
  2. Has human a-lactalbumin
  3. More balanced diet than normal cow milk for babies
  4. Was produced for the first time in 2001

Answer. 4. Was produced for the first time in 2001

Question 54. According to the latest estimates, how many documented varieties of basmati rice are grown in India?

  1. 30
  2. 27
  3. 118
  4. 125

Answer. 2. 27

Question 55. Which ingredient was present in high concentrations in genetically modified (GM) rice as compared to the usual rice?

  1. Protein
  2. Carbohydrates
  3. Na+ ions
  4. Vitamin A

Answer. 4. Vitamin A

Question 56. Which of the following cannot be achieved using PCR?

  1. Detect HIV in AIDS suspect.
  2. Detect mutations in cancer patients.
  3. Detect antigen-antibody interactions
  4. Detect specific microorganisms from soil.

Answer. 3. Detect antigen-antibody interactions

Question 57. In electrophoresis, the separation of DNA fragments is based on

  1. Charge
  2. Mass only
  3. Size
  4. Both (1) and (3)

Answer. 4. Both (1) and (3)

Question 58. Pick the odd one out:

  1. DNA microinjection
  2. RNA interference
  3. Retro virus mediated gene transfer
  4. Embryonic stem cell mediated gene transfer

Answer. 2. RNA interference

Question 59. In xenotransplantation, a protein that causes graft rejection usually comes from transgenic

  1. Cow
  2. Mice
  3. Pig
  4. Sheep

Answer. 3. Pig

Question 60. Transgenics has provided many pharmaceuticals in their milk for the treatment of diseases. Which one of the following has not been a successful story?

  1. Phenylketonuria
  2. SCID
  3. Emphysema (hereditary)
  4. CFTR

Answer. 2. SCID

Question 61. Which is not true with respect to transgenic animals and their contribution to human welfare?

  1. Transgenic mice are being tested to ensure safety of polio vaccine.
  2. Rosie’s milk contained human gene insulin.
  3. Transgenic cows produce milk with less lactose.
  4. Transgenic sheep grow more wool.

Answer. 2. Rosie’s milk contained human gene insulin.

Question 62. An antibacterial compound that prevents mastitis in cows is

  1. α-1-Antitrypsin
  2. Lysostaphin
  3. Lysozyme
  4. Alginate lyase

Answer. 2. Lysostaphin

Question 63. Choose the incorrect statement with respect to bioweapons:

  1. They are low-cost weapons.
  2. They cause more casualties than conventional weapons.
  3. They are extremely difficult to detect.
  4. Bacterium E. coli created letter scare in 2001.

Answer. 4. Bacterium E. coli created letter scare in 2001.

Question 64. A set of standards by which a community regulates its behavior and activities in relation to the biological world is termed as

  1. Biopatent
  2. Biopiracy
  3. Patent
  4. Bioethic

Answer. 4. Bioethic

Question 65. Nexia Biotechnologies spliced spider genes into the cells of lactating

  1. Cow
  2. Sheep
  3. Goat
  4. None of these

Answer. 3. Goat

Question 66. Nif gene for nitrogen fixation in cereal crops such as wheat and jowar is introduced by cloning

  1. Rhizobium meliloti
  2. Bacillus thuringiensis
  3. Rhizopus
  4. Rhizophora

Answer. 1. Rhizobium meliloti

Question 67. VNTRS represent

  1. New terminal regions in DNA
  2. Functional genes in DNA
  3. Split genes in sample DNA
  4. Specific non-coding sequences with unique tandem repeats

Answer. 4. Specific non-coding sequences with unique tandem repeats

Question 68. Sheep Dolly was genetically similar to

  1. The mother from which nucleated fertilized egg was taken
  2. The mother from which the nucleus of udder cell was taken
  3. The surrogate mother
  4. Both surrogate mother and nuclear donor mother

Answer. 2. The mother from which the nucleus of udder cell was taken

Question 69. How does a bacterial cell protect its own DNA from restriction enzymes?

  1. By adding methyl groups to adenines and cystosines.
  2. By reinforcing bacterial DNA structure with covalent phosphodiester bonds.
  3. By adding histones to protect the double-stranded DNA
  4. By forming “sticky ends” of bacterial DNA to prevent the enzyme from attaching.

Answer. 1. By adding methyl groups to adenines and cystosines.

Question 70. All cells contain the same genetic information. Why cannot cells other than stem cells differentiate into various tissues?

  1. As cells develop, their genetic makeup changes.
  2. Stem cells are the only cells that can be implanted.
  3. Stem cells are the only cells that do not have an X or Y chromosome and can, therefore, go into either a male or a female.
  4. As cells develop, some genes are turned off permanently.

Answer. 4. As cells develop, some genes are turned off permanently.

Question 71. Polymerase chain reaction technology (PCR-technique) is used for

  1. DNA identification
  2. DNA repair
  3. DNA amplification
  4. Cleave DNA

Answer. 3. DNA amplification

Question 72. Which scientists obtained interferon through recombinant DNA technology?

  1. Kohler and Milstein
  2. Charles Weisman
  3. Nathans and Smith
  4. An American firm

Answer. 2. Charles Weisman

Question 73. When the genotype of an organism is improved by the addition of a foreign gene, the process is called

  1. Tissue culture
  2. Genetic diversity
  3. Genetic engineering
  4. Plastic surgery

Answer. 3. Genetic engineering

Question 74. A genetically manipulated organism containing in its genome one or more inserted genes of another species is called

  1. Transposon
  2. Gene expression
  3. Transgenic organism
  4. Retroposons

Answer. 3. Transgenic organism

Question 75. The use of transgenic plants as biological factories for the production of special chemicals is called

  1. Molecular farming
  2. Molecular genetics
  3. Molecular mapping
  4. Dry farming

Answer. 1. Molecular farming

Question 76. Which vector is commonly used in the transfer of gene in a crop plant?

  1. Plasmids of B. subtilis
  2. Bacteriophages
  3. Ti plasmids of Agrobacterium
  4. E. coli phages

Answer. 3. Ti plasmids of Agrobacterium

Question 77. The tumor inducing capacity of Agrobacterium tumaefaciens is located in large extrachromosomal plasmid called

  1. Ti plasmid
  2. Ri plasmid
  3. Lambda phage
  4. Plasmid pBR322

Answer. 1. Ti plasmid

Question 78. Genetic engineering aims at

  1. Destroying wild gene
  2. Preserving defective gene
  3. Curing human disease by introducing new gene (hemophilia)
  4. All the above

Answer. 3. Curing human disease by introducing new gene (hemophilia)

Question 79. Taq polymerase which is used in amplification of DNA is related with

  1. Hybridoma technique
  2. PCR technique
  3. Gene cloning
  4. rDNA technology

Answer. 2. PCR technique

Question 80. DNA fragments separated by gel electrophoresis are shown. Mark the correct statement:

NEET Biology Bio Technology And Its Applications Question 80

  1. Band 3 contains more positively charged DNA molecules than band 1.
  2. Band 3 indicates more charge density than bands 1 and 2.
  3. Band 1 has longer DNA fragment than bands 2 and 3.
  4. All bands have equal length and charges but differ in base composition.

Answer. 3. Band 1 has longer DNA fragment than bands 2 and 3.

Question 81. Thermal cycle takes place in which technique?

  1. Gel electrophoresis
  2. PCR technique
  3. Centrifugation
  4. Southern blotting

Answer. 2. PCR technique

Question 82. Cry gene, which synthesizes crystal protein, is isolated from

  1. Bacillus thuringiensis
  2. Rhizobium
  3. Bacillus polymyxa
  4. Clostridium

Answer. 1. Bacillus thuringiensis

Question 83. Which of the following risks is associated with genetically modified food?

  1. Toxicity
  2. Allergic reaction
  3. Antibiotic resistance in microorganisms present in alimentary canal
  4. All of the above

Answer. 4. All of the above

Question 84. PCR technique is used in

  1. Production of transgenic microbes
  2. Production of genetically modified food
  3. Forensic investigation
  4. rDNA technique

Answer. 3. Forensic investigation

Question 85. TDF gene is a

  1. Gene present on X-chromosome
  2. Segment of RNA
  3. Proteinaceous factor
  4. Gene present on Y-chromosome

Answer. 4. Gene present on Y-chromosome

Question 86. BACS and YACs are

  1. Natural DNA obtained from bacteria and yeast
  2. Useful vectors for eukaryotic gene transfer
  3. Artificial DNA obtained from bacteria and yeast
  4. (2) and (3) both

Answer. 4. (2) and (3) both

Question 87. Gene therapy was first used in the treatment of

  1. Albinism
  2. Hemophilia
  3. SCID
  4. LIQID

Answer. 3. SCID

Question 88. DNA probe is used for

  1. DNA fingerprinting
  2. Detection of pathogenic bacteria
  3. Medical genetics to find whether a person carries a particular gene or not
  4. All of the above

Answer. 4. All of the above

Question 89. Bt cotton is resistant to

  1. Roundworm
  2. Flukeworm
  3. Bollworm
  4. Pinworm

Answer. 3. Bollworm

Question 90. A genetically engineered microorganism used successfully in the bioremediation of oil spills is a species of

  1. Pseudomonas
  2. Trichoderma
  3. Xanthomonas
  4. Bacillus

Answer. 1. Pseudomonas

Question 91. The first transgenic plant is

  1. Potato
  2. Tomato
  3. Tobacco
  4. Maize

Answer. 3. Tobacco

Question 92. Sheep Dolly was obtained by

  1. Cloning the udder cell (somatic cell) fused with uninucleated oocyte
  2. Cloning of gametes
  3. Tissue culture
  4. None

Answer. 1. Cloning the udder cell (somatic cell) fused with uninucleated oocyte

Question 93. E. coli are used in the production of

  1. Rifampicin
  2. LH
  3. Ecdyson
  4. Interferon

Answer. 4. Interferon

Question 94. A gaint rat is formed in the laboratory. What is the reason?

  1. Gene mutation
  2. Gene synthesis
  3. Gene manipulation
  4. Gene replication

Answer. 3. Gene manipulation

Question 95. The first cloned animal was

  1. Dolly sheep
  2. Polly sheep
  3. Molly sheep
  4. Dog

Answer. 1. Dolly sheep

Question 96. Introduction of food plants developed by genetic engineering is not desirable because

  1. Economy of developing countries may suffer
  2. These products are less tasty as compared to the already existing products
  3. This method is costly
  4. There is danger of introduction of viruses and toxins with introduced crop

Answer. 4. There is danger of introduction of viruses and toxins with introduced crop

Question 97. Which one of the following has found extensive use in genetic engineering work in plants?

  1. Bacillus coagulans
  2. Agrobacterium tumefaciens
  3. Clostridium septicum
  4. Xanthomonas citri

Answer. 2. Agrobacterium tumefaciens

Question 98. The maximum application of animal cell culture technology today is in the production of

  1. Vaccines
  2. Edible protein
  3. Insulin
  4. Interferon

Answer. 1. Vaccines

Question 99. Ti plasmid is often used for making transgenic plants. This plasmid is found in

  1. Yeast as a 2-mm plasmid
  2. Azotobacter
  3. Rhizobium of the roots of leguminous plants
  4. Agrobacterium

Answer. 4. Agrobacterium

Question 100. The cultivation of Bt cotton has been much in the news. Prefix “Bt” means

  1. “Barium-treated” cotton seeds
  2. “Bigger thread” variety of cotton with better tensile strength
  3. Produced by “biotechnology” using restriction enzymes and ligases
  4. Carrying an endotoxin gene from Bacillus thuringienisis

Answer. 4. Carrying an endotoxin gene from Bacillus thuringienisis

Question 101. An example of gene therapy is

  1. Production of injectable hepatitis B vaccine
  2. Production of vaccines in food crops such as potatoes which can be eaten
  3. Introduction of gene for adenosine deaminase in persons suffering from severe combined immunodeficiency (SCID)
  4. Production of test-tube babies by artificial insemination and implantation of fertilized eggs

Answer. 3. Introduction of gene for adenosine deaminase in persons suffering from severe combined immunodeficiency (SCID)

Question 102. Bacteria Pseudomonas is useful because of its ability to

  1. Transfer genes from one plant to another
  2. Decompose a variety of organic compounds
  3. Fix atmospheric nitrogen in the soil
  4. Produce a wide variety of antibiotics

Answer. 2. Decompose a variety of organic compounds

Question 103. Bacillus thuringiensis (Bt) strains have been used for designing novel

  1. Bioinsecticidal plants
  2. Bio-mineralization processes
  3. Biofertilizers
  4. Bio-metallurgical techniques

Answer. 1. Bioinsecticidal plants

Question 104. Which one of the following is a correct statement?

  1. “Bt” in Bt-cotton indicates that it is a genetically modified organism produced through biotechnology.
  2. Somatic hybridization involves the fusion of two complete plant cells carrying desired genes.
  3. The anticoagulant hirudin is being produced from transgenic Brassica napus seeds.
  4. “Flavr Savr” variety of tomato has enhanced the production of ethylene which improves its taste.

Answer. 3. The anticoagulant hirudin is being produced from transgenic Brassica napus seeds.

Question 105. The approximate number of genes contained in the genome of Kalpana Chowla was

  1. 40,000
  2. 30,000
  3. 80,000
  4. 1,00,000

Answer. 2. 30,000

Question 106. In transgenics, the expression of transgene in target tissue is determined by

  1. Reporter
  2. Enhancer
  3. Transgene
  4. Promoter

Answer. 4. Promoter

Question 107. Golden rice is a promising transgenic crop. When released for cultivation, it will help in

  1. Alleviation of vitamin A deficiency
  2. Pest resistance
  3. Herbicide tolerance
  4. Producing a petrol-like fuel from rice

Answer. 1. Alleviation of vitamin A deficiency

Question 108. Agrobacterium tumefaciens contains a large plasmid, which induces tumor in plants. It is termed as

  1. Ti plasmid
  2. Ri plasmid
  3. Recombinant plasmid
  4. Shine-Dalgarno sequence

Answer. 1. Ti plasmid

Question 109. Transgenic crops are modified through genetic engineering to develop natural resistance to insect pests. Which one is a transgenic plant?

  1. Tobacco and cotton
  2. Tomato and rice
  3. Maize and sugarcane
  4. Tomato and wheat

Answer. 1. Tobacco and cotton

Question 110. Genetically engineered human insulin is called

  1. Humulin
  2. Haematin
  3. Hybriodoma
  4. Hybrid

Answer. 1. Humulin

Question 111. Abzymes are

  1. Abnormal enzymes
  2. Enzymes acting on antibodies
  3. Antibodies acting as enzymes
  4. All of these

Answer. 3. Antibodies acting as enzymes

Question 112. Hybridoma technology was developed by

  1. Taggart, 1982
  2. Prie and Saxton, 1987
  3. Vitella et. al., 1982
  4. Kohler and Milstein

Answer. 4. Kohler and Milstein

Question 113. The technique for monoclonal antibody production was discovered by

  1. Steward and Skoog
  2. Arban and Haberlan
  3. Kohler and Milstein
  4. Lister and Koach

Answer. 3. Kohler and Milstein

Question 114. The first clinical gene therapy was given for treating

  1. Both sense and anti-sense RNA
  2. A particular hormone
  3. An antifeedant
  4. A toxic protein

Answer. 1. Both sense and anti-sense RNA

Question 115. Tobacco plants resistant to nematode have been developed by the introduction of DNA that produced (in the host cells)

  1. Diabetes mellitus
  2. Chicken pox
  3. Rheumatoid arthritis
  4. Adenosine deaminase deficiency

Answer. 4. Adenosine deaminase deficiency

Question 116. Which of the following Bt crops is being grown in India by the farmers?

  1. Cotton
  2. Brinjal
  3. Soybean
  4. Maize

Answer. 1. Cotton