Tag: zoology

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Questions Related to zoology

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

Biomagnification means

  1. Accumulation of pesticide through food chain

  2. Accumulation of pesticide in water

  3. Increased pesticide degradation

  4. Decrease pesticide degradation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Biomagnification refers to increase in concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted, and is thus passed on to the next higher trophic level. Thus, the correct answer is option A.

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

The term 'bio-magnification' refers to the 

  1. Increase in population size

  2. Increase in the concentration of non-degradable pollutants as they pass through the food chains

  3. Blowing up of environmental issues by man

  4. Growth of organisation due to food consumption
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Biomagnification (or bioaccumulation) refers to the increase in the concentration of non-degradable pollutants as they pass through the food chains. It is the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. 

Therefore, the correct answer is option B.

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

Increasing concentration of accumulated pollutant along food chain is

  1. Biomagnification

  2. Bioaccumulation

  3. Eutrophication

  4. Nutrient cycling
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A few toxic substances, often present in industrial wastewaters, can undergo biological magnification (biomagnification) in the aquatic food chain. 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 metabolised or excreted, and is thus passed on to the next higher trophic level in a food chain.

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

Biological magnification refers to

  1. Increase in the concentration of insecticide in animals

  2. Increase in the concentration of organophosphate in plants

  3. Decrease in the concentration of insecticide in animals

  4. Increase in the number of animals and plants in ecosystem
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Biomagnification is the accumulation or increasing concentration of lipophilic pesticides in the top members of the food chain. During biomagnification, the concentration of non-degradable pesticide like DDT goes on increasing along the food chain and highest values occur in the consumers of the top trophic level. So, the value of pesticide will go on increasing at each trophic level. 

Thus, the correct answer is option A.  

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

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

  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.
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

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

  1. Grasshopper

  2. Toad

  3. Snake

  4. Cattle
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. Bioaccumulation

  2. Biological amplification

  3. Biological half-life

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice zoology our environment - our concern biomagnification the effects of human activities on ecosystems bioaccumulation and biomagnification

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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.
Reveal answer Fill a bubble to check yourself
E Correct answer
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.

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

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

  1. Biological magnification

  2. Food web dynamics

  3. Succession

  4. Keystone predation

  5. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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.