Trophic Levels
- Trophic levels are the position of an organism in a food chain, and indicate how many organisms energy has passed through
- Trophic levels can be represented by numbers, beginning with producers at the first trophic level, and progressing to consumers at the second and third trophic levels, etc.
Trophic levels table
| Trophic level | Name of trophic level | Description of trophic level |
| 1 | Producers | Organisms that produce their own carbon compounds using, e.g. light energy |
| 2 | Primary consumers | Herbivores that feed on plant tissue |
| 3 | Secondary consumers | Carnivores that are predators of primary consumers |
| 4 | Tertiary consumers | Carnivores that are predators of secondary consumers |
| 5 | Quaternary consumers | Carnivores that are predators of tertiary consumers |
- Energy from sunlight enters the food chain at the first trophic level
- Producers convert light energy into chemical energy
- This occurs during photosynthesis
- This chemical energy is then transferred to primary consumers as they consume producers
- The chemical energy is then transferred from one consumer to the next as each organism is ingested by organisms higher up the food chain
- Primary consumers transfer energy to secondary consumers
- Secondary consumers transfer energy to tertiary consumers
- Tertiary consumers transfer energy to quaternary consumers
- Apex predators are at the very top of the food chain; these top predators have no predators that prey on them
- The chemical energy stored within apex predators can be passed on to decomposers when apex predators die and are decomposed
Trophic levels are the levels at which organisms feed in a food chain, and indicate the number of organisms through which energy has been transferred
- Trophic levels can also be identified within food webs, which give a clearer representation of the complex feeding relationships present in an ecosystem
- Note that some organisms have a varied diet, meaning that a species may be present at more than one trophic level in an ecosystem
- Species may be at different trophic levels in different food chains within a food web, e.g. in the food web below:
- Sparrowhawks are at the third, fourth and fifth trophic levels in the food chains:
- Species may be at different trophic levels in different food chains within a food web, e.g. in the food web below:
Grass → mouse → sparrowhawk
Tree → butterfly → robin → sparrowhawk
Tree → aphid → beetle → robin → sparrowhawk
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- Robins are at the third and fourth trophic levels in the food chains:
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Tree → caterpillar → robin → sparowhawk
Tree → aphid → beetle → robin → sparrowhawk
Food webs also contain trophic levels. Note that it is possible for an organism to be at different trophic levels in different food chains within a food web.