What does an energy pyramid illustrate?

An energy pyramid illustrates the flow of energy at each trophic level in an ecosystem, demonstrating how energy from primary producers, such as plants, is transferred to herbivores and then to carnivores. Each level of the pyramid represents a different trophic level; at the base are the producers, which capture energy from the sun, followed by primary consumers that feed on the producers, and then secondary and tertiary consumers that feed on the primary consumers.

The structure of the pyramid visually shows that energy decreases as you move up trophic levels. This decrease occurs due to energy loss through metabolic processes, heat production, and the inefficiency of energy transfer—typically only about 10% of the energy from one trophic level is available to the next. By illustrating this flow of energy, the energy pyramid helps to convey the interconnectedness of organisms within an ecosystem and the importance of each level in supporting higher levels.