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प्रश्न
List two important roles play in the environment by decomposers.
What is the role of decomposers in the ecosystem?
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उत्तर १
Role of decomposers:-
They recycle matter by breaking down the organic remains and waste products of plants and animals. These recycled matter are washed up and enter the soil from where plants absorb the nutrients again.
It also converts the waste matter back to unstable form.
उत्तर २
Various role played by decomposers in the ecosystem are:
- They clean the environment.
- They decompose biodegradable substances into useful substances.
- They release nutrients into soil by decomposing dead and decaying matter, thus making the soil fertile.
- They maintain the nutrient pool by returning back the nutrients in the pool.
उत्तर ३
Decomposers are microorganisms that act on dead and decaying bodies of producers and consumers and break them into simple inorganic compounds. They absorb some of the substances and release the rest into the environment to be recycled and to be used in future by producers. Thus, decomposers have a key role in the cycling of material in the biosphere and provide the raw materials to the producers. So in this way they make the soil fertile.
संबंधित प्रश्न
"Our food grains such as wheat and rice, the vegetables and fruits and even meat are found to contain varying amounts of pesticide residues." State the reason to explain how and why it happens?
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
The following statement is true or false :
In biology, human beings are called producers.
Explain the terms 'producer' and 'consumer'. Give two examples of producers and two of consumers.
Can the organisms of any trophic level be removed without causing any damage to the ecosystem? Will the impact of removing all the organisms in a trophic level be different for different trophic levels?
Write a common food chain of a pond ecosystem having four links.
Give one example of a simple food chain.
Which of the following represents a possible food chain found in a pond :
| Primary producers |
Primary consumers | Secondary consumers |
| (a) green algae | fish | mosquito larvae |
| (b) fish | green algae | mosquito larvae |
| (c) mosquito larvae | fish | green algae |
| (d) green algae | mosquito larvae | fish |
Which of the following 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
The sea water contains water beetles, tadpole, fish and weeds.
Which organism is a secondary consumer?
The following is a food chain that ends with human :
Do you think that the food chain given in this question can really be regarded as a food chain? Explain your answer.
Fill in the following blank with suitable word :
Grass → ........... → Human
The harmful chemical which is accumulating in human beings through food chain is :
(a) benzenehexachloride
(b) dichlorodiphenyltrichloroethane
(c) chlorofluorocarbon
(d) abscisic acid
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?
| 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 would happen if an organism is removed from the food chain?
In a food chain grasshopper gets energy by eating frog.
What are autotrophs?
Differentiate between herbivores and carnivores.
Assertion (A): The energy which passes to the herbivores does not come back to autotrophs.
Reason (R): The flow of energy in a food chain is unidirectional.
