Tag: zoology

Questions Related to zoology

The maximum biological magnification of DDT through food web can be seen in

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Algae

  2. Bacteria

  3. Higher plants

  4. Man

Show answer
Correct Option: D
Explanation:

A few toxic substances, often present in industrial wastes, can undergo biological magnification (biomagnification) in the food chain. 

Biomagnification refers to increase in the concentration of the toxic chemical at successive trophic levels. 
This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted and passed on to the next higher trophic level. This phenomenon is well-known for mercury and DDT. 
As man occupies the top most trophic level of all the food chains, man cannot pass the toxicant to any other organism. Thus, the correct answer is option D.

Match the following Column I with Column II.

Column I Column II
A. Zooplankton 1. 0.003 ppm
B. Small fishes 2. 2 ppm
C. Water 3. 25 ppm
D. Fish eating birds 4. 0.04 ppm
E. Big fishes 5. 0.5 ppm
zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. A - 2, B - 1, C - 4, D - 5, E - 3

  2. A - 4, B - 5, C - 1, D - 2, E - 3

  3. A - 4, B - 5, C - 3, D - 2, E - 1

  4. A - 4, B - 5, C - 1, D - 3, E - 2

Show answer
Correct Option: D
Explanation:
Column I Column II
A. Zooplankton 4. 0.04 ppm
B. Small fishes 5. 0.5 ppm
C. Water 1. 0.003 ppm
D. Fish eating birds 3. 2 ppm
E. Big fishes 2. 2 ppm

This shows the biomagnification of DDT in the aquatic ecosystem food chain.

Biomagnification refers to

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Rapid growth due to excessive intake of nutrients

  2. Increase in population size

  3. Decrease in population size

  4. Increase in concentration of nondegradable pollutants as they pass through food chain.

Show answer
Correct Option: D
Explanation:

Biomagnification is the property of a toxin to accumulate in the food chain by solubilizing with the adipose tissues of the living organisms. It is seen that the level of nondegradable pollutants increases as the food chain progresses. It means, the primary consumers will have more nondegradable pollutants concentration than the producers, the secondary consumers will have more than primary consumers and so on. The highest concentrations will be seen in the top carnivore. This is because the consumers at the successive trophic level consume more than the previous level to fulfil the energy requirements. Due to this, nondegradable pollutants keeps on accumulating in the successive trophic levels in higher concentrations. This process is called the biomagnification.

Hence, the correct answer is 'Increase in concentration of nondegradable pollutants as they pass through food chain.'

Cause of decline in population of reptiles and birds is

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Bioinsecticides

  2. Biofetilizers

  3. DDT

  4. Both A and B

Show answer
Correct Option: C
Explanation:
A. Bioinsecticides are the biological agents or organisms that are used to control pests.
B. Biofertilizers are the microorganisms that are used to supply nutrients in the soil and increase its fertility.
C. Dichlorodiphenyltrichloroethane or DDT is a crystalline, colourless and odourless compound which is used as an insecticide. DDT on runoff from the fields reach the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it enters the food chain. With each successive trophic level, concentration of DDT increases and this is known as biomagnification. 
High concentration of DDT disturbs the calcium metabolism of birds and reptiles and causes thinning of egg shells. and premature breaking. This leads to decline in their population.
So, the correct answer is 'DDT'.

Process by which insecticides like DDT reach man is

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Bioaccumulation

  2. Biomagnification

  3. Bioremediation

  4. Eutrophication

Show answer
Correct Option: B
Explanation:

DDT is an organochlorinated compound that was used as an insecticide. It is highly stable and is not degradable. It tends to stay in the adipose tissue of the living organisms. Due to this property, it enters the food chain and is accumulated at each trophic level. As the primary consumers eat more producers and similarly, secondary consumers eat more primary consumers, the organisms at the higher trophic levels will have an increased concentration of DDT. This process is called d the boimagnification.

Hence, the correct answer is 'Biomagnification'.

Pollution caused by persistent pesticides is more hazardous to

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Herbivores

  2. Producers

  3. First level carnivores

  4. Top carnivores

Show answer
Correct Option: D
Explanation:

Persistent pesticides are stable in chemical nature and tend to solubilize in the fats of the living organisms, these show persistence in the food chain. It is seen that the level of persistent pesticides increases as the food chain progresses. It means, the primary consumers will have more persistent pesticides concentration than the producers, the secondary consumers will have more than primary consumers and so on. The highest concentrations will be seen in the top carnivore. This is because the consumers at the successive trophic level consume more than the previous level to fulfil the energy requirements. Due to this, persistent pesticides keep on accumulating in the successive trophic levels in higher concentrations. This process is called the biomagnification.

Hence, the correct answer is 'Top carnivores'.

DDT residues are rapidly passed through food chain as DDT is

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Water soluble

  2. Moderately toxic

  3. Liposoluble

  4. Nontoxic to aquatic animals

Show answer
Correct Option: C
Explanation:
Dichlorodiphenyltrichloroethane or DDT is a crystalline, colourless and odourless compound which is used as an insecticide. DDT on runoff from the fields reach the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it gets incorporated in the food chain. It gets deposited in the fatty tissues of animals as it is fat soluble and cause serious health hazards. 
Hence, DDT residues are rapidly passed through food chain as DDT is fat soluble i.e. liposoluble.
So, the correct answer is 'Liposoluble'.

Biomagnification of DDT causes decline in bird population by

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Brining disturbance in calcium metabolism

  2. Thinning of egg shell

  3. Premature breaking of eggs

  4. All of the above

Show answer
Correct Option: D
Explanation:
Dichlorodiphenyltrichloroethane or DDT is a crystalline, colourless and odourless compound which is used as an insecticide. DDT on runoff from the fields reach the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it enters the food chain. With each successive trophic level, concentration of DDT increases and this is known as biomagnification. 
High concentration of DDT disturbs the calcium metabolism of birds and causes thinning of egg shells. and premature breaking. This leads to decline in their population.
Hence, all the options are correct.
So, the correct answer is 'All of the above'.

In an area where DDT has been used extensively, bird population declined because

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Birds stopped laying eggs

  2. Earthworms disappeared

  3. Cobras started feeding on birds

  4. Many birds eggs did not hatch

Show answer
Correct Option: D
Explanation:
Dichlorodiphenyltrichloroethane or DDT is a crystalline, colourless and odourless compound which is used as an insecticide. DDT on runoff from the fields reach the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it enters the food chain. With each successive trophic level, concentration of DDT increases and this is known as biomagnification. 
High concentration of DDT disturbs the calcium metabolism of birds and reptiles and causes thinning of egg shells. and premature breaking. This leads to decline in their population. Very high concentrations of DDT can result in failure of hatching of eggs.
So, the correct answer is 'Many birds eggs did not hatch'.


Calcium metabolism in birds gets disturbed due to effect of ___________

zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. Mercury

  2. Cadmium

  3. DDT

  4. Lead

  5. Copper

Show answer
Correct Option: C
Explanation:
Dichlorodiphenyltrichloroethane or DDT is a crystalline, colourless and odourless compound which is used as an insecticide. DDT on runoff from the fields reach the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it gets incorporated in the food chain. With each successive trophic level, concentration of DDT increases and this is known as biomagnification. 
High concentration of DDT disturbs the calcium metabolism of birds and reptiles and causes thinning of egg shells. and premature breaking. This leads to decline in their population.
So, the correct answer is 'DDT'.