Each Ecosystem consists of a group of levels. The first level is the Trophic level. The Trophic level consists of organisms that can produce their own food. Plants are among the main group of this level, using photosynthesis to turn the sunlight into food. The next level are the herbivores.
Herbivores feed upon the trophic level, consuming plants.
The next level are the carnivores. The carnivores feed upon the herbivores. The fourth level consist of tertiary consumers. These are carnivores that feed upon other carnivores. The last level consists of decomposers Decomers feed upon the remains of dead carnivores and return the organic matter back to the soil.