In the example above, the studied ecosystem had four. This final level is composed of the tertiary consumers who feed on the secondary consumers . The amount of biomass found in this trophic level is very small relative to the other levels. This is to be expected because of the processes, as described above, that cause continuously less energy to be available to successive consumers. Trophic pyramids have also been constructed to show the transfer of energy in caloric terms and the number of organisms found in each trophic level.
Food webs describe the complex patterns of energy flow in an ecosystem by modeling who consumes who.
The illustration below describes a portion of the food web for a typical tidal marsh ecosystem located on the southern coast of British Columbia. Typical tidal marsh food web.