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Illustrated below are some simple generalised food chains
Trophic levels in the food chains
The different steps or levels in a food chain form different trophic levels.The illustration below is self-explanatory. This is the ecosystem that can exist on land.
Thus a food chain of four levels is built up where green plants fix up the solar energy and prepare the food and make it, directly or indirectly, available for other consumers.
Significance of food chains
- The study of food chains helps in understanding food relationship and interdependence among various organisms in an ecosystem.
- The mechanism of transfer of food, energy and nutrients through various components of nature can also be studied
- The effect of the use of pesticides on the ecosystem can be studied. As several of them are not biodegradeable it goes on accumulating at every trophic level. Hence consumers at higher trophic levels will consume more poison along with their food. This phenomena is known as biological magnification.
- Indiscriminate use of DDT and other pesticides has an adverse effect on the food chain and consequently disturbs the ecosystem.




