Heterotropic organisms are organisms that cannot synthesize organic substances from inorganic ones and use ready-made organic compounds as a source of carbon and energy.
The term “heterotrophic” comes from the Greek words “heteros” - “other” and “trophe” - “nutrition”. Heterotrophs, unlike autotrophs, cannot absorb carbon dioxide and need ready-made organic substances.
Heterotrophs include animals, fungi, most bacteria and protists. They consume organic substances synthesized by autotrophs - plants, algae and some bacteria. Heterotrophs play an important role in the cycle of substances in the biosphere, decomposing complex organic compounds into simple inorganic substances, which are again used by autotrophs.
Thus, heterotrophs are organisms that feed on ready-made organic matter and are not capable of photosynthesis and chemosynthesis. They make up the majority of living organisms on Earth.