Biology - Ecology definitions IGCSE Edexcel

Food Web

A network of interconnected food chains showing the energy flow through part of an ecosystem

Food Chain

A chart showing the flow of energy (food) from one organism to the next beginning with a producer (e.g. tree → caterpillar → small bird → hawk).

Producer

An organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis

Consumer

an organism that gets its energy by feeding on other organisms

Community

All the different species living in a habitat e.g. Rock pools consisting of seaweeds, sea anemones, shrimps, fish, crabs & more.

Habitat

The place where an organism lives.

Decomposer

An organism that gets its energy from dead or waste organic matter.

Population

A group of organisms of the same species living in a habitat e.g. skin mites in a mattress.

Trophic level

The position of an organism in a food chain or food web.

Ecosystem

A unit containing all of the organisms and their environment in a given area and the abiotic conditions e.g. decomposing log or a lake

Primary consumers

These are usually herbivores which feed on plants.

Secondary consumers

These are organisms which kill for food. They are secondary or tertiary consumers.

Scavengers

These organisms feed on dead animals (carrion)

Predators

These are usually omnivores or carnivores and feed on the primary consumers.

Prey

These are the animals which are eaten by the predators.