As an ecological word, autotrophs are also called independent vegetative organisms, and its corresponding word is heterotrophs. Its original meaning refers to organisms that live and reproduce only with inorganic compounds as nutrients. In this classical concept, there is no difference between the two metabolic systems, that is, substrate oxidation for energy and nutrient reduction for carbon assimilation.

Today, this concept has been classified according to the nutrients oxidized into energy and their oxidation forms, according to the intake mode of carbon source nutrients and the synthesis mode of organic metabolites necessary for reduction and assimilation. And it is widely used only in the latter sense.

Autotrophic organisms that survive and reproduce by inorganic nutrition are the corresponding words of organic vegetative organisms. Organisms that assimilate carbon by using energy obtained from chemical dark reactions such as respiration or photochemical reactions are called chemoautotrophs and photoautotrophs respectively.

Type:

An organism that can obtain nutrients and energy needed for its own life activities from the process of synthesizing organic matter from inorganic substances. Green plants, such as algae, mosses, ferns and seed plants, rely on their unique chloroplasts and use solar energy to synthesize organic substances from CO2 and water to feed themselves.

Some chemically synthetic bacteria, such as nitrifying bacteria, sulfur bacteria, iron bacteria, etc. , can oxidize inorganic substances, and use the energy released by oxidation to make the required nutrients.