ABSTRACT
We show that basic physical laws of energy conservation are important and scale from the cellular to the ecosystem level. Respiration or metabolism is consistent among organisms, and this allows ecologists to develop general accounting models that can be applied to predict growth and production of organisms and trophic levels. The efficiency of the transfer of energy also can be estimated. A related approach, the metabolic theory of ecology (MTE), suggests that energy transfer among trophic levels should scale as a function of fundamental relationships among body size, temperature, and metabolic rate. We will compare and contrast these approaches, assessing how they may be applied to understanding trophic relationships in ecosystems.
