Question

Column I has various trophic levels in an ecosystem and column II has various organisms.

Match the organisms in column II with their respective trophic levels in column I and select the correct option.

Column I	Column II
p. Fourth trophic level	i. Wolf
q. Second trophic level	ii. Lion
r. First trophic level	iii. Cow
s. Third trophic level	iv. Grass

• A. p – iv, q – iii, r – ii, s – i
• B. p – i, q – ii, r – iii, s – iv
• C. p – ii, q – iii, r – iv, s – i
• D. p – iii, q – ii, r – i, s – iv

Answer 1

The correct option is C p – ii, q – iii, r – iv, s – i

A food chain is a linear sequence of organisms through which transfer of energy takes place in the form of food as one organism eats another organism.

The food chain is formed because of interdependence of organisms.

On the basis of the source of their food, organisms occupy a specific position in the food chain and that is known as their trophic level.

Producers belong to the first trophic level in the ecosystem. They are able to synthesise the food utilising the energy coming from the sun. These are called autotrophs and include the green plants (grasses, trees etc.) and phytoplankton.

The herbivores directly feed on the producers and hence are called primary consumers, they occupy the second trophic level. Organisms like zooplankton (in aquatic ecosystems), grasshoppers and cows (in terrestrial ecosystems) belong to this trophic level.

The primary carnivores feed on the herbivores and are called secondary consumers and they occupy the third trophic level. Birds, fishes and wolves are some common examples of secondary consumers.

The top carnivores (tertiary consumers) belong to the fourth trophic level and they feed on the primary carnivores. Examples include lions, tigers, etc.

Hence, the correct match is

(p) Fourth trophic level - (ii) Lion
(q) Second trophic level -(iii) Cow
(r) First trophic level - (iv) Grass
(s) Third trophic level - (i) Wolf