Explain food chain and trophic levels.

Explanation

Living organisms of an ecosystem depend on each other for their food requirement.
A series of organisms feeding on one another form a food chain. In food chain series of organisms take part at various biotic levels.
`rarr` Food chains generally consists of only three or four steps.

`rarr` Each step or level of the food chain forms a trophic level.
`rarr` The producers (autotrophs) are at the first trophic level. They absorb solar energy and convert it into chemical energy in the form of food through a process photosynthesis.
`rarr` The consumers (heterotrophs) obtain energy from other organisms in form of food.
`rarr` The herbivores or primary consumers are at the second. small carnivores or the secondary consumers at the third and large carnivores or the tertiary consumers form the fourth trophic level.