Another way of examining the energy flow through an ecosystem is to construct an energy pyramid. An energy pyramid depicts the amount of energy contained in each trophic level from the lowest, the producers, to the highest, the top carnivores. The amount of energy in each level is represented by a volume and the volumes are stacked from the lowest trophic level (producers) to the highest. As a general rule, only 10% of the energy in one level makes it to the next highest level. The rest is lost as heat through respiration.