Biology

Environment

Question:

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

Answer:

The advantages of using disposable paper cups over disposable plastic cups are:

  1. Paper cups are biodegradable. So, even if paper cups are thrown away after use, they will decompose (break down) automatically by the action of micro-organisms in due course of time. On the other hand, plastic cups are non-biodegradable. They will remain as such and pollute the environment.
  2. Paper cups can be disposed off by burning without causing much air pollution. On the other hand, burning of plastic cups produces toxic gases (poisonous gases) which causes too much air pollution.
previuos
next

Environment

Q 1.

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

Q 2.

A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.
(a) Construct a food chain for the pond.
(b) How many links are there in this chain ?

Q 3.

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

Q 4.

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

Q 5.

Explain some harmful effects of agricultural practices on the environ-ment.

Q 6.

Name any two abiotic components of an environment. [Delhi (C)]

Q 7.

In a food chain, 10,000 joules of energy is available to the producer. How much energy will be available to the secondary consumer to transfer it to the tertiary consumer? [All India ]

Q 8.

How does a biodegradable waste differ from a non-biodegradable waste ? Give two examples of non- biodegradable wastes which pollute our environment.

Q 9.

(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 10.

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

Q 11.

Where does all the energy in living organisms originate from ?

Q 12.

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

Q 13.

What is garbage ? What does garbage consist of ?

Q 14.

Name the various modes of waste disposal.

Q 15.

Write the harmful effects of ozone depletion.

Q 16.

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

Q 17.

We do not clean ponds or lakes but an aquarium needs to be cleaned periodically. Why ?

Q 18.

Name two waste materials which can be recycled.

Q 19.

Write the full form of CFC. Give its one harmful effect.

Q 20.

What is sewage ? How is sewage disposed of ?

Q 21.

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

Q 22.

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

Q 23.

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

Q 24.

Why did United Nations act to control the production of chlorofluorocarbons (CFCs) used in refrigerators? [Delhi]

Q 25.

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

Q 26.

What is the role of decomposers in the ecosystem? [Foreign]

Q 27.

Why are some substances non- biodegradable? [Foreign]

Q 28.

What is a food web?

Q 29.

What are the after effects of ozone depletion?

Q 30.

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

Q 31.

What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants ?

Q 32.

What are planktons ?

Q 33.

Explain the terms ‘producer’ and ‘consumer’. Give two examples of producers and two of consumers.

Q 34.

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

Q 35.

Write one or two words for each of the following statements/definitions :Write one or two words for each of the following statements/definitions :
(a) Each level of food chain where transfer of energy takes place
(b) The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem
(c) Organisms which depend on the producers for food either directly or indirectly
(d) The physical and biological world where we live in
(e) Selfcontained unit of living things and their non-living environment needing only sunlight for its functioning

Q 36.

Name the group of chemical compounds which damages the ozone layer.

Q 37.

Why are there rarely more than five links (or five organisms) in a food chain ?

Q 38.

What are the causes of depletion of ozone layer ? Which diseases are likely to be caused if the ozone layer will become thinner ?

Q 39.

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

Q 40.

What is meant by incineration ? For what purpose is it used ?

Q 41.

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

Q 42.

(a) With the help of a flow diagram, describe how energy from the sun flows through various trophic levels.
(b) Explain why, the flow of energy in the ecosystem is said to be unidirectional.

Q 43.

Write the common food chain of a pond ecosystem.

Q 44.

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

Q 45.

Which disease is caused in human beings due to depletion of ozone layer in the atmosphere? [Foreign]

Q 46.

How is ozone formed in the upper atmosphere? Why is the damage of ozone layer a cause of concern to us? State a cause of this damage. [Delhi(C)]

Q 47.

Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]

Q 48.

Why is it necessary to conserve our environment? [All India]

Q 49.

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

Q 50.

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