Heterotroph
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A Heterotroph (chemoorganotrophy: Greek ἕτερος heteros = another and τροφή trophe = nutrition) is an organism that uses organic substrates to get its chemical energy for its life cycle.[1] This contrasts with autotrophs such as plants which are able to directly use sources of energy such as light to produce organic substrates from inorganic carbon dioxide. The Cyanobacteria Synechocystis sp. PCC 6803 is an example of an autotroph.
Heterotrophs are known as consumers in food chains and obtain organic carbon by eating other heterotrophs or autotrophs. All animals are heterotrophic, as well as fungi and many bacteria. Some animals, such as corals, form symbiotic relationships with autotrophs and obtain organic carbon in this way. Furthermore, some parasitic plants have also turned fully or partially heterotrophic, while so-called carnivorous plants consume animals to augment their nitrogen supply but are still autotrophic.
For a species to be termed a heterotroph, it must obtain its carbon from organic compounds. If it obtains nitrogen from organic compounds, but not energy, it will be deemed an autotroph. If a species obtains carbon from organic compounds then there are two possible subtypes of these heterotrophs:
- photoheterotroph — obtains energy from light but must still obtain carbon in an organic form
- chemoheterotroph — obtains energy from the consumption of organic or inorganic molecules, and utilizes an organic source of carbon
[edit] See also
[edit] References
- ^ "heterotroph - definition of heterotroph by the Free Online Dictionary, Thesaurus and Encyclopedia.". www.thefreedictionary.com. http://www.thefreedictionary.com/Heterotroph. Retrieved on 2008-11-27.
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