An energy pyramid is a graphical representation of how energy flows in an ecosystem The pyramid consists of trophic, or nutritional, levels. It shows how energy decreases and becomes less available for organisms as it enters every trophic level, as well as the amount of energy lost to the atmosphere in the form of heat.
The energy pyramid is in an upright position, because energy loss always occurs in every trophic level. The food pyramid shows how chemical energy decreases as organisms consume it. There are smaller amounts of useful energy that reach the top, and energy is ultimately lost as heat.
Energy must be available and transferred for an ecosystem to function. Living things constantly invest energy to survive. By deriving energy from the sun, organisms produce food through photosynthesis. Different levels in the pyramid represent different groups of organisms that comprise a food chain. From the bottom to the top, the energy pyramid consists of producers who provide energy from nonliving sources, primary consumers who are herbivores that eat the producers, secondary consumers who are carnivores that eat the primary consumers and tertiary consumers who eat the secondary consumers. The consumers at the top of the pyramid have the least energy, that’s why they have relatively few numbers in most communities.