Primary producers: Organisms capable of producing organic matter from inorganic materials. Usually green plants.
Primary consumers: organisms that feed on producers such as green plants. Also called grazers or herbivores.
Secondary consumers: organisms that feed on primary consumers. Also called carnivores, or first level carnivores.
Tertiary consumers: organisms that feed on secondary consumers. Also called 2nd level carnivores.
Decomposers: organisms that feed on the remains of dead animals or other dead organic matter.