Prelims 2013 · archive
EasyWith reference to food chains in ecosystems, consider the following statements:
- 1.A food chain illustrates the order in which a chain of organisms feeds upon each other.
- 2.Food chains are found within the populations of a species.
- 3.A food chain illustrates the numbers of each organism which are eaten by others.
Which of the statements given above is/are correct?
Answer & explanation
Answer: (a) 1 only
A food chain shows who feeds on whom, in order, from producers upwards. It links different species at successive trophic levels, so it is not found inside one species' population. It does not record how many individuals are eaten. Only statement 1 is correct.
- ✓ 1. A food chain is a series of organisms at various biotic levels, each feeding on the one before it. For example: producer → herbivore → carnivore. Each step in the chain is a trophic level.
- ✗ 2. The members of a chain are different species at successive trophic levels: producers, herbivores and carnivores. Feeding relations run between species, not within the population of a single species.
- ✗ 3. A food chain shows only the order of feeding. The number or biomass of organisms at each trophic level is shown by ecological pyramids. These measure the standing crop as the mass of living organisms (biomass) or the number in a unit area.
Remember · A food chain shows the order of feeding between different species (producer → consumers). Numbers and biomass at each level are shown by ecological pyramids, not by the chain.
📘 Read it in NCERT: Class 10 Science, Ch 13 (practise this chapter) · Class 12 Biology, Ch 12 (practise this chapter)
Sources
- NCERT Class 10 · Science, Chapter 13 “This series or organisms taking part at various biotic levels form a food chain (Fig. 13.1). Each step or level of the food chain forms a trophic level.”
- NCERT Class 12 · Biology, Chapter 12 “The standing crop is measured as the mass of living organisms (biomass) or the number in a unit area.”
Question: UPSC Civil Services (Preliminary) 2013, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·