What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
Trophic levels refer to each step or level of a food chain. They represent the specific position an organism occupies in the food chain based on its feeding relationship.
An example of a food chain is: Grass → Deer → Lion. In this food chain, the different trophic levels are: First trophic level – Producers or autotrophs (Grass) which fix up solar energy; Second trophic level – Primary consumers or herbivores (Deer) which feed on producers; Third trophic level – Secondary consumers or carnivores (Lion) which feed on herbivores.
Explanation
The answer is based on the textbook definition that 'Each step or level of the food chain forms a trophic level.' The context clearly outlines the four trophic levels: autotrophs/producers at the first level, herbivores/primary consumers at the second, small carnivores/secondary consumers at the third, and larger carnivores/tertiary consumers at the fourth. A simple food chain example with three trophic levels (producer → herbivore → carnivore) demonstrates the concept effectively for a 3-mark answer.