Trophic level

Trophic Level

A Trophic level of an organism is 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 Energy Pyramid

Ecological pyramids place the primary producers at the base. They are then followed by primary consumers, which are eaten by secondary consumers, who are eaten by tertiary consumers, and so on. Each of these levels is a trophic level. The organisms at each level use the energy they receive to grow and reproduce, as well as to carry out other life processes, such as movement and digestion.

Energy Transfer

Energy transfer between trophic levels is generally inefficient, with about 90% of the energy at each level being used for metabolic processes and as heat. This inefficiency limits the length of food chains, with energy being lost at each successive level.

Trophic Dynamics

The concept of trophic dynamics was first introduced by Raymond Lindeman (1942), and it is central to many discussions in ecology. Lindeman's concept of the trophic dynamic view, is based on the efficiency of energy transfer.

See Also

• Food web
• Ecological pyramid
• Primary producers
• Primary consumers
• Secondary consumers
• Tertiary consumers
• Apex predators
• Raymond Lindeman

References

Trophic level Resources
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