Why does only a small fraction of the energy at one level of the food chain become available to the next level of the food chain?

Question

What will be an ideal response?

Answer 1

This is the case for several reasons. First, not every organism at one level of the food chain is eaten by an organism at the next level of the food chain. For example, not every plant is eaten by an herbivore. Second, when a consumer eats, the energy in its food goes into things other than building biomass. Specifically, some energy is lost in feces and other energy is used for maintenance. During all an organism's activities, a lot of energy is also lost to the environment as heat. So, by the time feces and maintenance have taken their share, only about 10 percent is left for building new biomass. This is why successive levels of an ecosystem have less and less biomass. This also explains why most ecosystems are limited in the number of levels in the food chain they can support.