<Li> Secondary consumers, carnivores, then consume the primary consumers, although omnivores also consume primary producers . Energy that had been used by the primary consumers for growth and storage is thus absorbed into the secondary consumers through the process of digestion . As with primary consumers, secondary consumers convert this energy into a more suitable form (ATP) during respiration . Again, some energy is lost from the system, since energy which the primary consumers had used for respiration and regulation of body temperature cannot be utilized by the secondary consumers . </Li> <Li> Tertiary consumers, which may or may not be apex predators, then consume the secondary consumers, with some energy passed on and some lost, as with the lower levels of the food chain . </Li> <Li> A final link in the food chain are decomposers which break down the organic matter of the tertiary consumers (or whichever consumer is at the top of the chain) and release nutrients into the soil . They also break down plants, herbivores and carnivores that were not eaten by organisms higher on the food chain, as well as the undigested food that is excreted by herbivores and carnivores . Saprotrophic bacteria and fungi are decomposers, and play a pivotal role in the nitrogen and carbon cycles . </Li> <P> The energy is passed on from trophic level to trophic level and each time about 90% of the energy is lost, with some being lost as heat into the environment (an effect of respiration) and some being lost as incompletely digested food (egesta). Therefore, primary consumers get about 10% of the energy produced by autotrophs, while secondary consumers get 1% and tertiary consumers get 0.1% . This means the top consumer of a food chain receives the least energy, as a lot of the food chain's energy has been lost between trophic levels . This loss of energy at each level limits typical food chains to only four to six links . </P>

Use a typical food chain to give a detailed account of energy transfer in an ecosystem