Trophic Levels (Edexcel IGCSE Science)

Exam board Pearson Edexcel · IGCSEUpdated 2026-07-02

Spec point — 4.6 · understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers

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.

A food chain starting with grass, then showing a grasshopper, a frog, a snake and an eagle a

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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