Heterotroph

A heterotroph is a creature that must ingest biomass to obtain its energy and nutrition . In direct contrast, autotrophs are capable of assimilating diffuse, inorganic energy and materials and using these to synthesize biochemicals. Green plants, for example, use sunlight and simple inorganic molecules to photosynthesize organic matter . All heterotrophs have an absolute dependence on the biological products of autotrophs for their sustenance—they have no other source of nourishment.

All animals are heterotrophs, as are most microorganisms (the major exceptions being microscopic algae and blue-green bacteria ). Heterotrophs can be classified according to the sorts of biomass that they eat. Animals that eat living plants are known as herbivores, while those that eat other animals are known as carnivores. Many animals eat both plants and animals, and these are known as omnivores. Animal parasites are a special type of carnivore that are usually much smaller than their prey , and do not usually kill the animals that they feed upon.

Heterotrophic microorganisms mostly feed upon dead plants and animals, and are known as decomposers. Some animals also specialize on feeding on dead organic matter, and are known as scavengers or detritivores. Even a few vascular plants are heterotrophic, parasitizing the roots of other plants and thereby obtaining their own nourishment. These plants, which often lack chlorophyll , are known as saprophytes.

Humans, of course, are heterotrophs. This means that humans can only sustain themselves by eating plants, or by eating animals that have themselves grown by eating plants. All of these foods must be specifically grown for human consumption in agricultural ecosystems, or be gathered from natural ecosystems. If humans and their societies are to be sustained over the long term, it can only be through the wise use of the species and ecosystems that sustain them. This is a fact, and a consequence of the inextricable links of humans with other species and with the products and services of ecosystems. The intimate dependency of humans on other creatures is a biological and ecological relationship that can be difficult for modern people to remember as they purchase their food in stores, and do not directly participate in its growth, harvesting, and processing.

See also Autotroph; Herbivore; Omnivore; Scavenger.

Bill Freedman

Heterotroph

The term heterotroph refers to a living organism that must ingest biomass to obtain its energy and nutrition. In contrast, autotrophs can take in inorganic sources of energy and use these to make their food. Green plants are autotrophs; they use sunlight and simple inorganic molecules to photosynthesize organic matter. All heterotrophs require the biological products of autotrophs for their sustenance—they have no other source of nourishment.

All animals are heterotrophs, as are most microorganisms (the exceptions being algae and blue-green bacteria). Heterotrophs can be classified according to the sorts of biomass that they eat. Animals that eat living plants are known as herbivores, while those that eat other animals are known as carnivores. Many animals eat both plants and animals, and these are known as omnivores. Animal parasites are a special type of carnivore that are usually much smaller than their prey, and do not usually kill the animals that they feed upon.

Heterotrophic microorganisms mostly feed upon dead plants and animals, and are known as decomposers. Some animals also specialize on feeding on dead organic matter, and are known as scavengers or detritivores. Even a few vascular plants are heterotrophic, parasitizing the roots of other plants and thereby obtaining their own nourishment. These plants, which often lack chlorophyll, are known as saprophytes.

Humans are heterotrophs. This means that humans can only sustain themselves by eating plants, or by eating animals that have, themselves, grown by eating plants. While humans can manufacture some nutrients, the raw material for the manufacture cannot be made, but must be ingested.

Bill Freedman

Heterotroph

A heterotroph is an organism that derives its nutritional carbon and energy by oxidizing (i.e., decomposing) organic materials. The higher animals, fungi , actinomycetes, and most bacteria are heterotrophs. These are the biological consumers that eventually decompose most of the organic matter on the earth. The decomposition products then are available for chemical or biological recycling .

See also Biogeochemical cycles; Oxidation reduction reactions

heterotroph An organism that is unable to manufacture its own food from simple chemical compounds and, therefore, consumes other organisms, living or dead, as its main or sole source of carbon. Often, single-celled autotrophs (e.g. Euglena) become heterotrophic in the absence of light.

heterotroph An organism that is unable to manufacture its own food from simple chemical compounds and therefore consumes other organisms, living or dead, as its main or sole source of carbon. Often, single-celled autotrophs (e.g. Euglena) become heterotrophic in the absence of light.