Why is improper disposal of waste a curse to environment?
Wastes pollute our environment — air, soil and water — and cause harmful effects on all living organisms.
Write the common food chain of a pond ecosystem.
Phytoplanktons and aquatic plants → small aquatic animals (larvae, insects etc.) → fish → bird
What are the advantages of cloth bags over plastic bags during shopping?
(a) Capable of carrying more things
(b) Made of biodegradable material
(c) Do not pollute our environment
(d) Can be reused
Why are crop fields known as artificial ecosystems?
Crop fields are man-made and some biotic and abiotic components are manipulated by humans.
Differentiate between biodegradable and non-biodegradable substances. Cite examples.
Biodegradable substances are broken down into simpler substances by biological processes. Example: wood, paper.
Non-biodegradable substances cannot be broken down into simpler substances by biological processes. Example: plastic, DDT.
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
(a) Environment/biosphere
(b) Trophic level
(c) Abiotic factors
(d) Consumers/heterotrophs
Explain the role of decomposers in the environment.
Decomposers break down dead and decaying organic matter and return the nutrients to the soil. They play an important role in nutrient recycling in the environment.
Select the mis-matched pair in the following and correct it:
(a) Biomagnification — Accumulation of chemicals at 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
(b) is not a matching pair.
Correct statement: Both biotic and abiotic components of environment constitute an ecosystem.
We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?
An aquarium is an artificial and incomplete ecosystem, whereas ponds and lakes are natural, self-sustaining and complete ecosystems.