Biology

Environment

Question:

What will be the consequence of the absence of decomposers in the ecosystem ?

Answer:

In the absence of decomposers, the dead bodies of plants and animals would keep lying as such and the elements of plant and animal bodies would never be returned to their original pool like soil, air and water. The cycling process of life and death would be disrupted. The nutrient pool will not be replenished and would exhaust soon.

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Environment

Q 1.

Why are some substances non- biodegradable? [Foreign]

Q 2.

Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.

Q 3.

Name two waste materials which can be recycled.

Q 4.

What is garbage ? What does garbage consist of ?

Q 5.

What is the functional unit of the environment comprising of the living and non-living components called ?

Q 6.

Which one of the following is not a terrestial ecosystem ?
Forest, Grassland, Aquarium, Desert

Q 7.

Where does all the energy in living organisms originate from ?

Q 8.

What is sewage ? How is sewage disposed of ?

Q 9.

Write the harmful effects of ozone depletion.

Q 10.

What would happen if the ozone layer in the atmosphere completely disappears ?

Q 11.

What is a food web?

Q 12.

If a harmful chemical enters a food chain comprising cat, mice and plants, which one of these organisms is likely to have the maximum concentration of the harmful chemical in its body ?

Q 13.

Write the common food chain of a pond ecosystem.

Q 14.

Why is ozone layer getting depleted at the higher levels of the atmosphere? [Delhi (C)]

Q 15.

What is the important function of presence of ozone in earth’s atmosphere? [Delhi]

Q 16.

List out the components in a food chain?

Q 17.

What is pollution?

Q 18.

What are planktons ?

Q 19.

(a) Define decomposers. Name one decomposer.
(b) What is the role of decomposers in the ecosystem ?

Q 20.

The number of malaria patients in a village increased tremendously when large number of frogs were exported from the village. What could be the cause for it ?

Q 21.

Explain how harmful chemicals enter our bodies.

Q 22.

Give a method for the disposal of household wastes such as left-over food, fruit and vegetable peels, and leaves of potted plants.

Q 23.

State two advantages of using disposable paper cups over disposable plastic cups.

Q 24.

What are the advantages of cloth bags over plastic bags during shopping?

Q 25.

Name two decomposers operating in our ecosystem. [All India 2011; Delhi]

Q 26.

Why is it necessary to manage our garbage?

Q 27.

Which of the following belong to the same trophic level ?
Tree ; Frog ; Snake ; Grass ; Lizard

Q 28.

What are the various steps of food chain called ?

Q 29.

A food chain represents a unidirectional flow of X. What is X ?

Q 30.

(a) Describe an activity to show that while paper is biodegradable but plastic (say, polythene) is non-
biodegradable.
(b) Explain why, some materials are biodegradable but some are non-biodegradable.

Q 31.

(a) What is meant by non-biodegradable waste materials ? Give two examples of non-biodegradable wastes.
(b) Which of the following materials are biodegradable ?Animal bones, Iron nails, Plastic mugs, Leather belts, Silver foil

Q 32.

(a) Define an ecosystem. Give examples of any two ecosystems.
(b) List the biotic and abiotic components of an ecosystem.

Q 33.

Which radiations are absorbed by ozone layer ?

Q 34.

Explain how, harmful ultraviolet radiations of sunlight are prevented from reaching the earth’s surface.

Q 35.

‘If we excessively use pesticides to protect the crops from diseases, then it may cause long-term damage to mankind’. Justify this statement.

Q 36.

How can the wastes such as paper, plastic and metal objects be disposed of ?

Q 37.

How are most of the solid wastes in urban areas disposed of ?

Q 38.

Suggest any four activities in daily life which are eco-friendly.

Q 39.

Indicate the flow of energy in an ecosystem. Why is it unidirectional ? Justify.

Q 40.

How is the increase in demand for energy affecting our environment adversely?

Q 41.

Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]

Q 42.

Construct an aquatic food chain showing four trophic levels. [All India]

Q 43.

What will happen if we kill all the organisms in one trophic level? [Delhi]

Q 44.

Define ‘trophic level’. [Delhi]

Q 45.

What are the various steps in a food chain called? [Delhi]

Q 46.

What is the important function of presence of ozone in earth’s atmosphere? [Delhi]

Q 47.

What happens when higher energy ultraviolet radiations act on the oxygen at the higher level of the atmosphere? [All India]

Q 48.

What is a food chain?

Q 49.

What are the after effects of ozone depletion?

Q 50.

Name two natural ecosystems and two artificial ecosystems.