UPSC Prelims 2015 GS Paper I · Q84 of 100 Environment & Ecology easy

Which one of the following is the best description of the term 'ecosystem'?

  1. (a) A community of organisms interacting with one another
  2. (b) That part of the Earth which is inhabited by living organisms
  3. (c) A community of organisms together with the environment in which they live ✓ UPSC's answer
  4. (d) The flora and fauna of a geographical area

Why the answer is (c)

• An ecosystem (Tansley, 1935) is a community of living organisms (biotic components) interacting with each other and with their non-living environment (abiotic components — soil, water, air, sunlight) as a functional unit — option (c).

• Option (a) is only the biotic community; (b) is the biosphere; (d) is merely the flora and fauna without the environment.

• Hence option (c).

Why the other options are wrong

(a) A community of organisms interacting with one another
A community alone is the biotic part, not the ecosystem.
(b) That part of the Earth which is inhabited by living organisms
That describes the biosphere.
(d) The flora and fauna of a geographical area
Flora and fauna alone omit the environment.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2015, held on 23 August 2015. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

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