The producers that are responsible for the conversion of the inorganic molecules into the organic compounds are known as photoautotrophs and the process they use is known as photosynthesis for the conversion while the producers which are responsible for the production of food mainly from carbon dioxide and other inorganic compounds are known as chemoautotrophs and the process they use is known as chemosynthesis. Examples of photoautotrophs and chemoautotrophs include green plants and methanogens respectively.