Producers, consumers, and decomposers are all descriptions of living things. Which living things produce food from sunlight? Which living things consume other things that were alive? Decomposers live mostly on dead things. Some examples are fungus and mushrooms and bacteria that live in compost.

Producers generate new material using energy from non-biological sources (e.g. sunlight). Consumers get energy by eating other life-forms. Decomposers get their energy from eating dead life-forms or the waste of still-living life-forms.