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प्रश्न
Give reason to justify the following: Flow of energy in a food chain is unidirectional.
उत्तर
Food chain is a linear relationship of 'eating' and 'being eaten' between the organisms present in an ecosystem. According to the energy transfer law, only 10% energy is transferred from one trophic level to another. The energy that is captured at one trophic level cannot move back to the previous trophic level. That is why, the flow of energy in a food chain is always unidirectional.
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संबंधित प्रश्न
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Which of the following belong to the same trophic level?
Tree ; Frog ; Snake ; Grass ; Lizard
Which of the following are decomposers of dead organisms?
| Bacteria | Fungi | Viruses |
| (a) no | yes | yes |
| (b) yes | no | yes |
| (c) yes | yes | no |
| (d) yes | yes | yes |
In the food chain comprising of a snake, grass, insect, and frog, the secondary consumer is :
(a) insect
(b) snake
(c) frog
(d) grass
Explain why, the flow of energy in the ecosystem is said to be unidirectional.
Answer the following question.
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.
(a) Why is the maximum concentration of pesticides found in human beings?
(b) Give one method which could be applied to reduce our intake of pesticides through food to some extent.
(c) Various steps in a food chain represent :
(a) Food web
(b) Trophic level
(c) Ecosystem
(d) Biomagnification
(d) With regard to various food chains operating in an ecosystem, man is a:
(a) Consumer
(b) Producer
(c) Producer and consumer
(d) Producer and decomposer
______ are organisms that are able to produce their own organic food.
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.
Which statement is correct with respect to the food chain?
Use of several pesticides which results in excessive accumulation of pesticides in rivers of ponds, is a matter of deep concern. Justify this statement.
