Tag: our environment - our concern

Questions Related to our environment - our concern

Drinking of mineral water with very low level of pesticides (about 0.02 ppm) for long periods may

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

  1. Produce immunity against mosquito.

  2. Cause leukemia (blood cancer) in most people.

  3. Cause cancer of the intestine.

  4. Lead to accumulation of pesticide residues in body fat.

Show answer
Correct Option: D
Explanation:

In India, prolonged use of 0.02-13 ppm of DDT (pesticide) can be detected in the body fat of the people. Most toxic pollutants such as pesticides do not degrade easily and therefore accumulate within the body of an organism specially in fat deposited portion. This process is known as biochemical concentration. 

Therefore, the correct answer is option D.

Which one of the following organisms is likely to show the highest concentration of DDT, once it has been introduced into the ecosystem?

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

  1. Grasshopper

  2. Toad

  3. Snake

  4. Cattle

Show answer
Correct Option: C
Explanation:

Biomagnification is process of transfer of toxic substance such as DDT and Mercury, in increasing concentration in successive trophic level of food chain.
Pollutant increases in concentration from Producers → Primary consumers → Secondary consumers →Tertiary consumers → Top consumer. 

In the given question, only snake represents the tertiary consumer, so the concentration of DDT will be highest in snake. Grasshopper, toads and cattles are usually primary and secondary consumers. 
Therefore, the correct answer is option C.

The process of accumulating higher and higher amounts of a toxic material such as PCBs within the body of any animal is called

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

  1. Bioaccumulation

  2. Biological amplification

  3. Biological half-life

  4. None of the above

Show answer
Correct Option: A
Explanation:
The process of accumulation of chemicals in the living cells in increasing concentration is known as bioaccumulation. When there is excessive use of the pesticides such as Polychlorinated biphenyls (PCBs) against the harmful pests, they are accumulated in the food products. When these products are consumed, the chemicals deposit in the fatty tissues of the host. This phenomenon is called bioaccumulation of the chemicals in the living system. Thus the correct answer is option A.

Read the passage and answer the following questions:
Six pairs of bald vulture were released into the wild in Germany. Four of the pairs of birds successfully nested and raised young. Two of the pairs nested near an industrial complex that released waste products (PCBs) into a nearby lake. These birds laid eggs, but the embryos failed to develop.The eggshells of the embryos that failed to develop were tested and were found to contain more PCBs than the nearby plants and insects. This is due to

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

  1. Biomagnification

  2. Increased levels of PCBs in the lake

  3. The resistance of the insects to PCBs

  4. Failure of the plants to take up PCBs

  5. Absorption of PCBs from the nesting site into the eggshell

Show answer
Correct Option: A
Explanation:

Slow metabolism and excretion of PCB cause its accumulation in tissues of organisms (plants and insects of that area). Top carnivores exhibit more accumulation of PCBs when they feed on lower trophic levels; the process is called as biomagnification. Vultures are top carnivores and hence their eggshells exhibited the higher amount of PCB due to the process of biomagnification. Thus, the correct answer is option A.

A fish-eating bird species was found to have a specific, heavy metal concentration of 700,000 ppt (parts per trillion). The conclusion based on the data is

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

  1. Air pollution may have caused this bird species to inhale dangerous amounts of heavy metals while migrating.

  2. The entire population of the bird species, from which this sample was taken, died.

  3. The population of this bird species exploded, causing an ecosystem imbalance.

  4. Pollutants tend to collect in areas of land where this bird species nests.

  5. This bird species is at a high trophic level on the food chain.

Show answer
Correct Option: E
Explanation:

Organisms at higher trophic levels in a food chain can experience biomagnification, which is the accumulation of environmental toxins (such as heavy metals) in living tissue. Organisms at lower trophic levels accumulate small amounts of toxins through their food. Because organisms at the next highest trophic level eat many of the lower-level organisms, they take in higher amounts of the toxins. At the highest trophic levels, increased concentrations of toxins in organisms’ tissues can be dangerous. This bird tissue has a high concentration of a specific heavy metal, so the species must be at a high trophic level. Therefore, the correct answer is option E.

Which of the following is the building of pesticides in food chain?

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

  1. Biological magnification

  2. Food web dynamics

  3. Succession

  4. Keystone predation

  5. None of the above

Show answer
Correct Option: A
Explanation:

Slow metabolism and excretion of pesticides cause their accumulation in fat tissues of organisms (biomagnifications), particularly affecting the top consumers (carnivores) causing the decrease in their population size. Pesticides in water (through agricultural runoff) concentrate in fishes and then in Osprey (Ospreys feed on fishes). Biological Magnification is an accumulation of substances over subsequent trophic levels in the food chain. Thus, the correct answer is option A.

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'.