trophic level
trophic level, step in a nutritive series, or food chain, of an ecosystem. The organisms of a chain are classified into these levels on the basis of their feeding behaviour.
- Related Topics:
- trophic pyramid
- food chain
- consumer
- decomposer
- producer
The first and lowest level contains the producers, green plants. The plants or their products are consumed by the second-level organisms—the herbivores, or plant eaters. At the third level, primary carnivores, or meat eaters, eat the herbivores; and at the fourth level, secondary carnivores eat the primary carnivores. These categories are not strictly defined, as many organisms feed on several trophic levels; for example, some carnivores also consume plant materials or carrion and are called omnivores, and some herbivores occasionally consume animal matter. A separate trophic level, the decomposers or transformers, consists of organisms such as bacteria and fungi that break down dead organisms and waste materials into nutrients usable by the producers.