Biology

Environment

Question:

Define ozone layer?

Answer:

Ozone is a form of oxygen. Each ozone molecule is made of three oxygen atoms, so its chemical formula is O3. But unlike oxygen, ozone is a poisonous gas, and an increase in its concentration at ground level is harmful. But in the stratosphere, where ozone exists naturally, it blocks out the sun’s ultraviolet rays and is a lifesaver.

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Environment

Q 1.

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

Q 2.

What is pollution?

Q 3.

Name two predators of snakes in a food web operating in a forest ecosystem.

Q 4.

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

Q 5.

Which category of organisms forms the starting point of a food chain ?

Q 6.

(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 7.

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

Q 8.

Give an example to illustrate that indiscriminate use of pesticides may result-in the degradation of the environment. [All India]

Q 9.

Explain the effects of human activity on the environment?

Q 10.

Where does all the energy in living organisms originate from ?

Q 11.

Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) Ultraviolet rays can cause skin…………………
(b) Pesticides enter the food chain at the…………………. level
(c) Grass →…………….→Human
(d) Lettuce →…………….→ Fox
(e) Plants→ Antelope→  …………….

Q 12.

Write the harmful effects of ozone depletion.

Q 13.

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

Q 14.

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

Q 15.

What are the two main components of our environment? [Delhi]

Q 16.

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

Q 17.

Name two natural ecosystems and two artificial ecosystems.

Q 18.

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

Q 19.

What are the various steps of food chain called ?

Q 20.

Which organisms belong to third and fourth trophic levels in the food chain comprising the following ?
Rats, Plants, Hawk, Snakes

Q 21.

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 ?

Q 22.

(a) What is meant by ‘environment’ ?
(b) What type of substances are the major pollutants of the environment ? Name two such substances.
(c) Name the organisms whose uncontrolled activities are damaging the environment.
(d) Explain why, it is better to use paper bags than plastic bags.

Q 23.

Name the process in which a harmful chemical enters the food chain and gets concentrated at each trophic level.

Q 24.

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

Q 25.

Name the various modes of waste disposal.

Q 26.

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

Q 27.

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

Q 28.

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

Q 29.

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

Q 30.

(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 31.

Write the common food chain of a pond ecosystem.

Q 32.

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

Q 33.

Why are crop fields known as artificial ecosystems?

Q 34.

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

Q 35.

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

Q 36.

Name the wastes which are generated in your house daily. What measures would you take for their disposal?

Q 37.

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

Q 38.

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

Q 39.

Why are green plants called ‘producers’? [All India]

Q 40.

State two problems caused by the non- biodegradable waste that we generate in our daily life. [All India (C)]

Q 41.

Explain the phenomenon of “biological magnification” How does it affect organisms belonging to different trophic levels particularly the tertiary consumers? [Delhi]

Q 42.

Define ‘trophic level’. [Delhi]

Q 43.

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

Q 44.

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

Q 45.

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

Q 46.

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

Q 47.

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

Q 48.

What step is being taken to limit the damage to the ozone layer? [Foreign]

Q 49.

Why are some substances non- biodegradable? [Foreign]

Q 50.

Select two non-biodegradable substances from the following waste generated in a kitchen: spoilt food, paper bags, milk bags, vegetable peels, tin cans, used tea leaves. [Delhi]