Producers mainly refer to green plants, including all higher plants, algae and lichens that can carry out photosynthesis. In addition to green plants, there are photoautotrophic microorganisms and chemoautotrophic microorganisms that can convert inorganic substances into organic substances by solar energy or chemistry. Producers can synthesize organic matter from inorganic matter, so they must be autotrophs.

Of course, everything in the world is not absolute. Sometimes, producers can also be heterotrophic or semi-autotrophic, such as insect-eating plants such as pig excrement beans and laurel, or parasitic plants such as dodder.