Tag: our environment - our concern

Questions Related to our environment - our concern

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'.

Increase in the concentration of the toxicant at successive trophic levels is known as

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

  1. Biomagnification

  2. Biodeterioration

  3. Biotransformation

  4. Biogeochemical cycling

Show answer
Correct Option: A
Explanation:

Biomagnification, also known as bio-amplification or biological magnification, is the increasing concentration of a substance, such as a toxic chemical, in the tissues of tolerant organisms at successively higher levels in a food chain. The substances become increasingly concentrated in tissues or internal organs as they move up the chain. Bioaccumulants are substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted.

So the correct answer is 'Biomagnification'.

Match the columns and find correct option.

I(Organisms) II(DDT in ppm)
(a) Zooplankton (p) $0.003$ ppm
(b) Small fishes (q) $2.0$ ppm
(c) Water (r) $25.0$ ppm
(d) Fish eating birds (s) $0.04$ ppm
(e) Big fishes (t) $0.5$ ppm
zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

  1. a-s, b-t, c-p, d-r, e-q

  2. a-s, b-t, c-r, d-q, e-p

  3. a-s, b-t, c-p, d-q, e-r

  4. a-q, b-p, c-s, d-t, e-r

Show answer
Correct Option: A
Explanation:
  • Biomagnification refers to an increase in the concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolized or excreted, and is thus passed on to the next higher trophic level. This phenomenon is well-known for mercury and DDT. 
  • Biomagnification of DDT in an aquatic food chain as follows,
  • (a)Zooplankton - (s)0.04ppm.
  • (b)Small Fishes - (t) 0.5ppm.
  • (c)Water             -(p)0.003ppm.
  • (d)Fish-eating birds -(r)25.0ppm.
  • (e)Big Fishes - (q)2 ppm.

If a water body is contaminated with toxicant, its biomagnification will be more marked in

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

  1. Plankton

  2. Small fish

  3. Birds

  4. Water

Show answer
Correct Option: C
Explanation:

 It is seen that the level of toxicant increases as the food chain progresses. It means, the primary consumers will have more toxicant 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, toxicant keeps on accumulating in the successive trophic levels in higher concentrations. This process is called the biomagnification. So, planktons will have least and birds will have the most toxicant presence.

Hence, the correct answer is 'Birds'.

Which of the following statements is related to biological magnification?

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

  1. There is a progressive increase in biological activities through trophic levels

  2. There is a progressive increase in the level of harmful substances through trophic levels.

  3. There is a progressive increase in the body weight through trophic levels.

  4. There is a progressive increase in the number of organisms through trophic levels.

Show answer
Correct Option: B
Explanation:

The toxic substances which cannot be metabolized get accumulated at a particular trophic level. This leads to increase in the concentration of the toxicant at successive trophic levels. This phenomenon is called as biological magnification and well-known for mercury and DDT. Higher the trophic level of an organism in the food chain greater will be the magnification of toxic chemicals.

So, the correct answer is option B.