Ecosystems are composed of a variety of living organisms that can be classified as producers , consumers , or decomposers . Producers or autotrophs , are organisms that can manufacture the organic compounds they use as sources of energy and nutrients . Most producers are green plants that can manufacture their food through the process of photosynthesis . Consumers or heterotrophs get their energy and nutrients by feeding directly or indirectly on producers. We can distinguish two main types of consumers.
Herbivores are consumers that eat plants for their energy and nutrients.
Organisms that feed on herbivores are called carnivores . Carnivores can also consume other carnivores. Plants and animals supply organic matter to the soil system through shed tissues and death. Consumer organisms that feed on this organic matter, or detritus , are known as detritivores or decomposers . The organic matter that is consumed by the detritivores is eventually converted back into inorganic nutrients in the soil.