▪ Energy enters most communities as light, where it is absorbed by autotrophs (e.g. plants) and converted into chemical energy via photosynthesis
▪ Energy then gets passed to the primary consumer (herbivore) when they eat the plant, and then gets passed to successive consumers (carnivores) as they are eaten in turn
▪ Energy is lost between trophic levels in the form of heat through cell respiration, faeces, tissue loss and death.
▪ Some of this lost energy is used by detritivores and saprotrophs. These in turn also lose energy in the form of heat through cell respiration.
à Only ~10% of energy is passed from one trophic level to the next, the rest is lost.
Because ~90% of energy is lost between trophic levels, the number of trophic levels are limited as energy flow is reduced at higher levels