Trophic levelsSpec 4.7.4.1
In short
Trophic levels are the feeding levels of a food chain, numbered from level 1. Level 1 is producers (plants and algae), level 2 is herbivores (primary consumers), and levels 3 and 4 are carnivores (secondary and tertiary consumers). Apex predators are carnivores with no predators. Decomposers secrete enzymes onto dead matter, then soluble food molecules diffuse in.
Trophic levels can be represented by numbers, starting at level 1 with plants and algae. Further trophic levels are numbered subsequently according to how far the organism is along the food chain.
| Trophic level | Organisms | Name |
|---|---|---|
| Level 1 | Plants and algae make their own food | Producers |
| Level 2 | Herbivores eat plants and algae | Primary consumers |
| Level 3 | Carnivores that eat herbivores | Secondary consumers |
| Level 4 | Carnivores that eat other carnivores | Tertiary consumers |
Apex predators are carnivores with no predators.
Decomposers
Decomposers break down dead plant and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism.
(opens full size in a new tab)Decomposers secrete enzymes outside their bodies, onto the dead material. Small soluble food molecules then diffuse in. Decomposers do not take in the dead material and then digest it.
Written and checked against the AQA GCSE Biology (8461) specification · Updated October 2026