An Introduction To Ecological Energetics Trophic Level Efficiency: the ratio of production by a trophic level to the production of the previous level, as in the ratio of production of herbivores to that of primary producers. Trophic Level: a stage in a food web occupied by organisms that feed on the same general type of food, used in diagramming the energy flow within an ecosystem. Carnivores, herbivores, and plants constitute different trophic levels. Trophic Structure: the energy flow of an ecosystem as illustrated by the feeding relationships in food chains and food webs. Utilization Efficiency: the ratio of energy assimilated by a given trophic level to the energy produced by the previous trophic level.Utilization efficiency generally increases with trophic level. Ecological efficiency: the ratio of the energy ingested by a trophic level to the energy ingested by the previous trophic level in the food web; the percentage of useful energy transferred from one trophic level to the next. Ecological Growth Efficiency: the ratio of the energy in production to the energy ingested (or absorbed by plant surfaces) by an organism or trophic level. Detritus Food Chain: the transfer of food energy primarily from dead organic matter, which is consumed and broken down into detritus by microorganisms, which in turn are consumed by detrivores and then by predators of detrivores. Grazing Food Chain: transfer of food energy in which vegetation or algae is eaten by animals (herbivores) that in turn are eaten by carnivores. The grazing food chain being one of two basic types of food chain, the other being the detritus food chain.