What happens to the majority of energy within an ecosystem as it moves up trophic levels?

As energy moves up the trophic levels within an ecosystem, the majority of it is released as heat. This phenomenon can be attributed to the second law of thermodynamics, which states that energy transformations are not 100% efficient. As organisms consume energy, they utilize it for various metabolic processes such as growth, reproduction, movement, and maintenance of body functions. During these processes, a significant portion of the energy is converted into heat, which is then dissipated into the environment.

This concept is often illustrated by the energy pyramid, where only about 10% of the energy at one trophic level is available to the next level. The remaining energy is lost largely as heat, which is why there is less available energy at higher trophic levels. In this way, the flow of energy through an ecosystem is characterized by significant loss at each step, primarily as heat, rather than being transformed into nutrients or stored as biomass.