What does an energy pyramid measure?

An energy pyramid measures the total amount of energy available in each trophic level of an ecosystem. It illustrates how energy flows through a food chain, starting from the primary producers, such as plants, at the bottom, to the top carnivores at the peak. Each level represents a different stage in the energy transfer process, highlighting that energy decreases as one moves up the pyramid due to energy loss from metabolic processes, heat, and other factors.

In a typical energy pyramid, the producers have the most energy, which supports fewer consumers at higher trophic levels. This concept reflects the inefficiencies of energy transfer—approximately only 10% of the energy from one level is passed to the next. Therefore, the focus on the total amount of energy provides a clearer understanding of the productivity and sustainability of ecosystems as compared to just counting organisms or assessing size or species diversity.