Trophic level

From Wikipedia, the free encyclopedia

First trophic level. The plants in this image, and the algae andphytoplankton in the lake, areprimary producers. They take nutrients from the soil or the water, and manufacture their own food byphotosynthesis, using energy from the sun.

The trophic level of an organismis the position it occupies in a food chain. The word trophic derives from the Greek τροφή (trophē) referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism is from the start of the chain is a measure of its trophic level. Food chains start at trophic level 1 with primary producers such as plants, move to herbivores at level 2, predators at level 3 and typically finish with carnivores or apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a food "web". Ecological communities with higher biodiversity form more complex trophic paths.