In nature, living organisms have various ways of obtaining energy and nutrients in order to carry out all their biological functions. One of these nutritional pathways is called heterotrophy, which consists of obtaining nutrients from various sources of organic carbon.
In this article by Ecologista Verde we deal with the issue of heterotrophic organism: what are they, characteristics and examples, with which you will be able to understand more fully this form of nutrition so widely extended in nature.
What are heterotrophic organisms
Heterotrophs (from the Greek, "heteros" = "other" and "trophos" = "food") are organisms that obtain their nutrients and energy from the consumption of other organisms. Unlike autotrophs, heterotrophic organisms do not have the ability to produce organic matter from inorganic substances by fixing carbon, but they must take organic carbon from another living being. Are the secondary or tertiary consumers within the food web, depending on whether they feed on autotrophic or other heterotrophic organisms. Animals are heterotrophs, as are fungi, a large number of bacteria, and archaea.
Characteristics of heterotrophic organisms
Heterotrophic organisms obtain their food from organic carbon sources present in the environment they inhabit, since they are unable to transform inorganic carbon into organic, unlike autotrophic organisms. Furthermore, heterotrophic organisms play the role of consumers in ecosystems they occupy, exerting control over the populations of lower links in the food chain and maintaining stability in the middle. It should be noted the existence of two forms of heterotrophy: photoheterotrophy and chemoheterotrophy.
- Photoheterotrophy: Photoheterotrophic organisms use light as an energy source but cannot depend exclusively on carbon dioxide as the sole carbon source, so they also use organic compounds that they take from the environment.
- Chemoheterotrophy: For their part, chemoheterotrophs obtain their energy from the ingestion of preformed organic energy sources, such as lipids, carbohydrates and proteins, that have been synthesized by other organisms. They obtain their energy through a chemical reaction that releases energy by breaking down organic molecules.
Thus, both photoheterotrophs and chemoheterotrophs need to feed on living or dead organisms (or even waste) to obtain energy and process organic matter. To expand the information and for you to know better how to feed on organisms, in these other Green Ecologist articles we talk about the autotrophic organisms:
- Difference between autotrophic and heterotrophic organisms with examples.
- Autotrophic organisms: what are they, characteristics and examples.
Examples of heterotrophic organisms
Among the heterotrophic organisms we find herbivores, carnivores and omnivores, but not only within the animal kingdom. So these are some examples of heterotrophic organisms.
Examples of herbivorous heterotrophic organisms
Herbivores, also known as the primary consumers of the food chain, feed on plant species to obtain nutrients, such as the cow (Bos primigenius taurus), Rabbit (Oryctolagus cuniculus) or the camel (Camelus dromedarius). Most herbivorous organisms have symbiotic organisms in their digestive systems that facilitate the digestion of cellulose, which is the main component in the plant wall, into forms of energy that they are able to use.
Within the herbivory, we find frugivorous species that feed partially or exclusively on fruits, as is the case of bonobos (Paniscus bread) or fruit flies (Drosophila melanogaster). In addition, they also include nectarivorous organisms, whose main food is nectar, such as the hummingbird (Hummingbird sp.) or the European bee (Apis mellifera).
Heterotrophic organisms that are carnivores
Another type of heterotrophic organisms are carnivores, which are usually predators, classified as secondary consumers -if they feed on primary consumers-, such as the eagle owl (Bubo bubo), or tertiary -if they feed on primary and secondary consumers- such as the lion (Panthera leo) or the white shark (Carcharodon carcharias). Carnivores obtain their energy mainly from lipids stored in herbivores. Carnivores can also be scavengers, if they feed on dead animals, such as the black vulture (Aegypius monachus).
Heterotrophic animals that are omnivores
Omnivores are also considered heterotrophic organisms, since they are animals that feed on both plants and animals, including humans (Homo sapiens sapiens) or the brown bear (Ursus arctos).
Here we show you more about which animals are omnivores with simple examples.
Fungi are also heterotrophic
Among the heterotrophic organisms, fungi also stand out, which have a hyphal system that grows underground and from which they secrete digestive enzymes that degrade the substrate and allow the absorption and assimilation of nutrients. Many fungi are parasites (such as Hepatic fistulin) and feed on a host organism without killing it, although most are saprophytes (as Nyctalis agaricoides), which implies that they feed on dead or decomposing material and recycle nutrients, which become available to organisms that, in turn, feed on fungi. This is the reason behind the great importance of the role that fungi play as decomposers in ecosystems, since they recycle at all levels of the nutrient cycle.
For you to expand your knowledge about mushrooms, we recommend this other article by Green Ecologist about the Fungi Kingdom: what it is, characteristics, classification and examples.
Within the set of photoheterotrophic organismsSome examples stand out, such as heliobacteria, such as those of the genus Heliobacterium or Heliobacillus, which can be found in the soil (especially in rice crops), as well as certain types of proteobacteria and non-sulfurous purple bacteria, such as those of the genus Rhodopseudomonas, which use organic acids without sulfur for energy. For their part, among the chemoheterotrophic organisms, Fungi and protozoa stand out, which absorb organic carbon from the environment, as well as manganese oxidizing bacteria.
From Ecologist Verde, we hope that with this article on heterotrophic organisms: what they are, characteristics and examples, we have been able to resolve any doubts regarding these forms of life and nutrition so homogeneously established in nature.
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