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प्रश्न
Explain how the pesticides enter a food chain and subsequently get into our body.
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उत्तर १
A large number of pesticides and chemicals are used to protect our crops from pests and diseases. Some of these chemicals are washed down from the soil, while some enter the water bodies. From the soil, they are absorbed by plants along with water and minerals; and from the water bodies, they are taken up by aquatic plants and animals. This is how these chemicals enter the food chain. As these chemicals cannot decompose, they accumulate progressively at each trophic level. This increase in the concentration of harmful chemicals with each step of the food chain is called biomagnification. As human beings occupy the top level in any food chain, these chemicals get accumulated in our bodies.
उत्तर २
Pesticides are non-biodegradable wastes which pass along the food chain from crops to man or other animals and birds and harm them.
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संबंधित प्रश्न
Which organisms belong to third and fourth trophic levels in the food chain comprising the following?
Rats, Plants, Hawk, Snakes
What would happen to the number of rabbits and grass plants if the number of foxes decreased?
Explain why, the flow of energy in the ecosystem is said to be unidirectional.
Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun :
Small algae → Zooplankton → Fish → Big fish
What percentage of sun's energy falling on the leaves of green plants is utilised by the plants in the process of photosynthesis and stored as chemical energy of food?
(a) 99 per cent
(b) 10 per cent
(c) 1 per cent
(d) 20 per cent
| Human body is made up of five important components, of which water is the main component. Food, as well as potable water, are essential for every human being. The food is obtained from plants through agriculture. Pesticides are being used extensively for a high yield in the fields. These pesticides are absorbed by the plants from the soil along with water and minerals and from the water bodies these pesticides are taken up by the aquatic animals and plants. As these chemicals are not biodegradables, they get accumulated progressively at each trophic level. The maximum concentration of these chemicals gets accumulated in our bodies and greatly affects the health of our mind and body. |
- Why is the maximum concentration of pesticides found in human beings? (1)
- Give one method which could be applied to reduce our intake of pesticides through food to some extent. (1)
- Various steps in a food chain represent: (1)
- Food web
- Trophic level
- Ecosystem
- Biomagnification
- With regard to various food chains operating in an ecosystem, man is a: (1)
- Consumer
- Producer
- Producer and consumer
- Producer and decomposer
Animals that eat both plants and animals are called as Carnivores.
DDT was sprayed in a lake to regulate breeding of mosquitoes. How would it affect the trophic levels in the following food chain associated with a lake? Justify your answer.
Use of several pesticides which results in excessive accumulation of pesticides in rivers of ponds, is a matter of deep concern. Justify this statement.
Which of the following statements is correct?
