An autotroph (from the Greek autos = self and trophe = nutrition) is an organism that produces complex organic compounds from simple inorganic molecules using energy from light or inorganic chemical reactions it only makes energy from light. Autotrophs are the producers in a food chain. Plants and other organisms which carry out photosynthesis are photoautotrophs (or phototrophs). Bacteria which derive energy from oxidizing inorganic compounds (such as hydrogen sulfide, ammonium and ferrous ir… (More on Autotroph)