Heterotroph

Overview of cycle between autotrophs and heterotrophs.

A heterotroph (Greek ἕτερος heteros = "another", "different" and τροφή trophe = "nutrition", "growth") is an organism that uses organic carbon for growth by consuming other organisms.[1] This contrasts with autotrophs, such as plants, which can directly use sources of energy such as light to produce organic substrates from carbon dioxide.

Contents

Ecology

Heterotrophs function as consumers in food chains: they obtain organic carbon by eating other heterotrophs or autotrophs. They break down complex organic compounds that are produced by 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 while remaining autotrophic.

Flowchart to determine if a species is autotroph, heterotroph, or a subtype

Biologists distinguish two types of heterotroph:

  1. photoheterotroph — obtains energy from light, but needs carbon in an organic form for growth. These are mostly certain kinds of bacteria.(Plants are photoautotrophs — not heterotrophs at all.)
  2. chemoheterotroph — needs an organic source of carbon for both energy source and growth. All animals and fungi are chemoheterotrophs.

Organotrophs and Lithotrophs

These terms refer to the chemical reactions that are involved in biosynthetic processes or respiration. Phototrophs and chemotrophs can be either lithotrophic or organotrophic.

See also

References