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प्रश्न
What would happen to the number of rabbits and grass plants if the number of foxes increased?
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उत्तर
If the number of foxes increases, it will lead to foxes consuming more rabbits as food, which will lead to a decrease in the number of rabbits. Hence, grass plants will grow denser as there will be fewer rabbits to consume them.
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संबंधित प्रश्न
Why are green plants called producers?
Why are plants called producers?
Name one decomposer.
What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
What is the difference between the food habits of organisms belonging to the first and the third trophic levels? Give one example each of the organisms belonging to these two trophic levels.
Consider the food chain :
Grass → Deer → Lion
What will happen if all the lions are removed from the above food chain?
At which trophic level a person is feeding when he is eating bread.
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 does garbage consist of?
Explain why, a food chain usually cannot have more than three or four steps.
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
Which of the following limits the number of trophic levels in a food chain?
(a) insufficient food supply from producer level
(b) decrease in energy at higher trophic levels
(c) increase in the number of organisms at higher trophic levels
(d) accumulation of harmful chemicals at higher trophic levels
Most of the water surface of a lake is covered with algae. This algae is part of the food chain which also includes small fish, bird, larvae and big fish. Which of the following will obtain the maximum energy?
(a) big fish
(b) bird
(c) larvae
(d) small fish
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.
Which other organism you could write in place of bird in the above food chain?
| 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
Which group of organisms are not constituents of a food chain?
- Grass, lion, rabbit, wolf
- Plankton, man, fish, grasshopper
- Wolf, grass, snake, tiger
- Frog, snake, eagle, grass, grasshopper
Study the picture given below showing three food chains (a), (b) and (c) and answer the following questions:
- Name the type of ecosystems that exist in food chains (b) and (c).
- The first trophic level in all food chains is producers. Why? What percentage of solar energy do these producers capture for their use?
- Why are the arrows shown in the diagram in one direction only and not vice versa? Justify.
