(a) What is an ecosystem? List its two main components.
(b) We do not clean ponds or lakes, but on aquarium needs to be cleaned regularly. Explain.
Ecosystem is self-sustaining system where the biotic and abiotic organisms of various communities interact with each other.
(a) The two components of the ecosystem are - Biotic and Abiotic. Biotic system consists
of all the living organisms of particular area like humans, animals etc., and the nonliving or abiotic component consists of air, mineral soil, water and sunlight.
(b) Ponds are the example of natural ecosystem whereas, the aquarium is an example of artificial ecosystem. Ponds do not need to be cleaned but aquarium needs to be cleaned, because aquarium does not contain soil and decomposing bacteria which helps in degrading complex organic substance into simple inorganic substance. But pond has this facility. Therefore, it does not need to be cleaned.