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प्रश्न
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?
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उत्तर
X could be phytoplankton.
(b) Phytoplankton → Tadpole → Water beetle → Fish
(c) 'Aquatic food chain' is the general name of food chains such as the one described above.
(d) (i) In the given food chain, the water beetle is the secondary consumer.
(ii) The phytoplankton is the producer.
(iii) The fish is the tertiary consumer.
(iv) The tadpole is the primary consumer.
(e) Sun → Phytoplankton→ Tadpole→ Water beetle→ Fish
20,000 J→ 200 J → 20 J → 2 J → 0.2 J
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संबंधित प्रश्न
In the following food chain, 20,000 J of energy was available to the plants. How much energy would be available to man in this chain?
Plants → Sheep → Man
What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
What is a trophic level?
What is a food chain?
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 |
Which of the following is not a producer?
(a) grass
(b) zooplankton
(c) phytoplankton
(d) paddy
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Name two zooplanktons.
Some hunters are roaming in the plush green forest of Africa. They spot a deer and kill it. They decide to roast the deer there and then and eat it. When the hunters had just finished enjoying the feast of roasted deer, a lion attacks them. The lion kills one of the hunters and eats his flesh.
(a) write a food chain which provides food to lion in this case.
(b) Which animal (other than deer) the lion could look for food if he did not get the hunter as prey?
(c) Which other animal in the forest could have been in place of lion?
(d) How does the above food chain differ form the food chain such as : plants → goat → man?
What would happen to the number of grass plants and foxes if the number of rabbits increased?
In a food chain consisting of grass, frog, bird and insects, where will the concentration of the harmful chemicals be maximum?
Which of the following gets the minimum energy through the food chain in an ecosystem?
(a) carnivore
(b) large carnivore
(c) producer
(d) herbivore
A food chain comprises of cat, seed-eating bird, plants, and dog. The organism which will have the maximum concentration of harmful pesticides coming through the food chain is most likely to be :
(a) cat
(b) plants
(c) dog
(d) seed-eating bird
The ten per cent law is associated with
(a) transfer of energy from various trophic levels to decomposers in a food chain
(b) transfer of ATP energy into muscular energy
(c) transfer of chemical energy from one organism to another
(d) transfer of sun's energy to the organisms called producers.
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:
- Food web
- Trophic level
- Ecosystem
- Biomagnification (1)
- With regard to various food chains operating in an ecosystem, man is a:
- Consumer
- Producer
- Producer and consumer
- Producer and decomposer (1)
Primary consumers that eat plants are called _______.
Write the importance of the food chain.
Green plants utilize ______ percent of sun’s energy to prepare their food by the process of photosynthesis.
Which of the following is an autotroph?
______ are organisms that are able to produce their own organic food.
