| Producers / Primary Producers / Autotrophs | | The animal at the top trophic level of a food chain / web. |
| Consumers / Heterotrophs | | Consumers of primary producers. Make up the second trophic level of a food chain / web. |
| Primary consumer / Herbivores | | a complex network of interrelated food chains - more realistic than a simple food chain (which is unlikely to exist in a real ecosystem). |
| Secondary consumer (Carnivores and Omnivores) | | A consumer which eats only plants. |
| Tertiary consumer (Carnivores and Omnivores) | | Consumers of primary producers and / or primary consumers. Make up the third trophic level of a food chain / web. |
| Top carnivore | | are typically plants or algae, and produce their own food using photosynthesis and form the first trophic level in a food chain. Exceptions include chemosynthetic organisms which produce food without sunlight. |
| Omnivore | | Obtain their energy from dead organisms by secreting enzymes that break down the organic matter e.g. bacteria and fungi. |
| Herbivore | | Consumer of secondary consumers. Make up the fourth trophic level of a food chain / web. |
| Decomposer | | feed on autotrophs or other heterotrophs to obtain energy (includes herbivores, carnivores, omnivores, detritivores and decomposers). Make up the first trophic level of a food chain/web. |
| Detritivore | | Derive their energy from detritus or decomposing organic material dead organisms or faeces or parts of an organism, eg shed skin from a snake, a crab carapace. Examples include Snails, slugs, blowfly, maggots, vultures. These eat, rather than decompose, organic matter. |
| Food chain | | the position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains. |
| Food web | | is the flow of energy from one organism to the next. It shows the feeding relationships between species in an ecosystem. Arrows connect the species, usually pointing towards the species that consumes the other: so in the direction of transfer of biomass (and energy). |
| Trophic level | | A consumer which eats both plants and animals. |
