Trophic Levels (Edexcel IGCSE Biology (Modular)): Revision Note
Exam code: 4XBI1
Trophic Levels
The trophic level is the position of an organism within a particular food chain
Within a food web an organism can be in different food chains and have a different trophic level for each
Level | Organisms | Energy transfer |
|---|---|---|
First trophic level | Producers (plants, algae) | Producers convert light energy from the sun into chemical energy stored in glucose during photosynthesis. |
Second trophic level | Primary consumers | Eat producers and transfer chemical energy from plant tissues into their own. |
Third trophic level | Secondary consumers | Eat primary consumers and gain energy from their tissues. |
Fourth trophic level | Tertiary consumers | Eat secondary consumers and gain energy from their tissues. |
At any trophic level organisms produce waste, or may die; the energy in waste or dead matter is then transferred to decomposers (bacteria and fungi)
Decomposers break down dead organisms and waste, recycling nutrients back into the ecosystem
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