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प्रश्न
What is ten per cent law? Explain with an example.
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उत्तर
According to the 10 per cent law, only 10 per cent of the energy entering a particular trophic level of organisms is available for transfer to the next higher trophic level.
In the following food chain, only 10 per cent of energy is transferred to the next trophic level. The flow of energy is shown below.
Plants → Grasshopper → Frog → Snake → Hawk
100,000J 10,000J 1,000J 100J 10J
When the energy available at the producer level is 100,000 J, only 10 J of energy is available to the hawk.
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संबंधित प्रश्न
What will happen if we kill all the organisms in one trophic level?
Consider the food chain :
Grass → Deer → Lion
What will happen if all the lions are removed from the above food chain?
Write down a food chain in the sea.
At which trophic level a person is feeding when he is eating bread.
In a food chain, the initial organism is usually :
(a) photosynthetic
(b) herbivore
(c) saprophytic
(d) parasitic
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 |
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Name the organism which Y could be.
What would happen to the number of rabbits and grass plants if the number of foxes decreased?
Write the percentage of energy transferred from autotrophs to the next level in a food chain.
Fill in the following blank with suitable word :
Pesticides enter the food chain at the ...........level
How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?
In the food chain given below, if the amount of energy available at fourth trophic level is 5 kJ, what was the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
(a) 500 kJ
(b) 50 kJ
(c) 5000 kJ
(d) 5 kJ
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.
"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.
| 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
What are decomposers? What will be the consequence if the decomposers are completely eradicated from an ecosystem? Give justification in support of your answer.
If 100 J energy is available at the producer level in a food chain then the energy available to the secondary consumer will be ______.
______ are organisms that are able to produce their own organic food.
Each level in the food chain is called a ______ level.
