Figure 20.13 The energy pyramid of Cedar Bog Lake. Most of the energy assimilated in this lake ecosystem is found in producers such as algae. Because energy is lost as it is converted from one trophic level to the next, considerably less energy is found in primary consumers such as zooplankton and secondary consumers such as fish.

Data from R. L. Lindeman, The trophic-dynamic aspect of ecology, Ecology 23 (1942): 399–417.