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प्रश्न
"Energy flow in food chains is always unidirectional". Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.
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उत्तर
The producers convert solar energy into chemical energy in the form of organic compounds. The primary consumers (herbivores) derive their nutrition from the producers. According to the energy transfer law, only 10% of energy is transferred from one trophic level to the other. So, the energy that is consumed by the producers does not revert back to the Sun and the energy transferred to the herbivores does not come back to the producers. It keeps on moving to the next trophic level in a unidirectional way. Hence, the flow of energy in the food chain is always unidirectional.
A large number of pesticides and chemicals are used to protect the crops from pests and diseases. Some of these chemicals are washed down from the soil and enter the water bodies. From the water bodies, they are taken up by aquatic plants and animals. In this way, these chemicals enter the food chain. As they 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 accumulate in their bodies.
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संबंधित प्रश्न
At which trophic level a person is feeding when he is eating eggs.
What will happen if deer is missing in the food chain given below?
Grass → Deer → Tiger
Organisms of a higher trophic level which feed on several types of organisms belonging to a number of lower trophic levels constitute the ______.
With the help of a food chain, explain how biological magnification of harmful chemicals can occur.
Explain why, a food chain usually cannot have more than three or four steps.
The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
(a) What could organisms X be?
(b) Write a food chain comprising of all the four organisms mentioned.
(c) What is the general name of the food chains like the one written above?
(d) Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
(e) If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?
A forest ecosystem having a lot of green plants has some foxes, lions and rabbits in it.
(a) Write a food chain comprising all the four organisms mentioned above.
(b) Name (i) one herbivore, and (ii) two carnivores, in this food chain.
(c) Name the link which is a predator as well as a prey.
(d) Name (i) second trophic level, and (ii) third trophic level.
(e) Which link of this food chain can feed on second trophic level as well as third trophic level, independently?
(f) If the sun provides 1000 J of energy to the plants, then how much energy will be transferred to fox through the food chain.
A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.
Write the food chain comprising all the organisms mentioned above.
In an ecosystem, herbivores represent ______.
______ are organisms that are able to produce their own organic food.
