Short Answer Type Questions
Q.1. Why is improper disposal of waste a curse to environment?
Ans. Improper disposal of waste is a curse to environment and its components such as because it pollutes the environment- air, water, soil and cause harmful effects on living organisms. For example, passage of sewage into water body cause eutrophication, killing of animals and acts as a source of water borne pathogens.
Q.2. Write the common food chain of a pond ecosystem.
Ans. Phytoplanktons and aquatic plants—› Zooplanktons, small aquatic animals, larvae, insects, etc. —› Fish —› Bird.
Q.3. What are the advantages of cloth bags over plastic bags during shopping?
Ans. Advantages of cloth bags are as follows—
(i) They are strong and more durable than plastic bags.
(ii) They are capable of carrying more things.
(iii) They are washable.
(iv) They are made of biodegradable material and do not pollute the environment.
(v) They can be recycled.
(vi) They can be reused.
Q.4. Why are crop fields known as artificial ecosystems?
Ans. Crop fields are known as artificial ecosystems because they are man-made and some biotic and a biotic components are maintained, nourished and reaped by human beings.
Q.5. Suggest one word for each of the following statements/definitions:
(a) The physical and biological world where we live in.
(b) Each level of food chain where transfer of energy takes place.
(c) The physical factors like temperature, rainfall, wind and soil of an ecosystem.
(d) Organisms which depend on the producers either directly or indirectly for food.
Ans. (a) Environment or biosphere.
(b) Trophic level.
(c) Abiotic factors.
(d) Consumers or heterotrophs.
Q.6. Select the mis-matched pair in the following and correct it.
(a) Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain
(b) Ecosystem — Biotic components of environment
(c) Aquarium — A man-made ecosystem
(d) Parasites — Organisms which obtain food from other living organisms.
Ans. (b) Ecosystem — Both biotic and abiotic components of the environment.
Q.7. We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?
Ans. An aquarium is an artificial and incomplete ecosystem compared to ponds or lakes which are natural, self- sustaining and complete ecosystems where there is a perfect recycling of materials.
Long Answer Type Questions
Q.8. Suggest any four activities in daily life which are eco-friendly.
Ans. (i) Use of cloth bags instead of plastic bags for shopping.
(iii) Harvesting of rainwater and preventing wastage of resources.
(iv) Use of compost.
Q.9. Give two differences between food chain and food web.
Q.10. Name the wastes which are generated in your house daily. What measures would you take for their disposal?
Ans. The wastes generated daily are kitchen wastes, paper wastes (like newspaper, bags, envelopes), plastic bags, vegetable and fruit peels, dust and empty cartons, etc.
Measures for disposal
(i) Separation of bio degradable and non - biodegradable recyclable and non-recyclable wastes.
(ii) Safe disposal of plastic bags.
(iii) Preparation of compost from kitchen wastes for home garden or given to waste collector for disposal.
(iv) Paper waste can be given for recycling.
Q.11. Suggest suitable mechanism (s) for waste management in fertiliser industries.
Ans. Fertiliser industries produce mainly two types of wastes—gaseous and effluents which can be minimised as follows:
(i) Gaseous wastes are passed through wet scrubbers to dissolve the pollutant gases.
(ii) Effluents should be treated before discharge into surrounding environment.
(iii) By having a unit to recover sulphur.
(iv) By recycling the water to minimise discharge of effluents.
(v) By using treated water to irrigate plants in the green belt area.
Q.12. What are the by-products of fertiliser industries? How do they affect the environment?
Ans. The by-products of fertiliser industries are oxides of nitrogen and sulphur, i.e. gases such as SO2 and NO. They pass into the atmosphere and cause extensive air pollution, and are responsible for acid rain, which is harmful to living beings. Acid rain pollutes the soil and harm crop production. It also affects the buildings and monuments.
Q.13. Explain some harmful effects of agricultural practices on the environment.
Ans. Some harmful effects of agricultural practices on the environment are as follows:
(i) Use of fertilisers change the chemistry of soil and kills useful microbes.
(ii) Use of non-biodegradable pesticides leads to bio-magnification.
(iii) Extensive cropping causes loss of soil fertility.
(iv) Use of ground water for agriculture has resulted in lowering water table.
(v) Natural ecosystem s and habitat have been damaged during clearing of land for agriculture.