Trophic Levels : The several steps in a food chain in which the transfer of food or energy takes place are called trophic levels.
There are four trophic levels:
(i) First trophic level - Producers (Plants)
(ii) Second trophic level – Primary consumers.
(iii) Third trophic level - Secondary consumers.
(iv) Fourth trophic level - Top consumers.
For example : A food chain operating in a grassland is given below :
Grass \(\rightarrow \) Insects \(\rightarrow \) Frog\(\rightarrow \) Eagle
Here we have:
-Grass as producers.
-Insects as primary consumers.
-Frog as Secondary consumers.
-Eagle as Top consumers