Do you know how the beings that live on Earth are nourished and get energy? We know that animals get energy when they eat, but what about, for example, algae or other beings that don't have a mouth and a digestive system?
In this article on our site we will see the definition of autotrophic and heterotrophic beings, the differences between autotrophic and heterotrophic nutrition and some examples to understand it better. Continue reading the article to learn more about the beings that populate our planet!
Definition of autotroph and heterotroph
Before explaining the definition of autotroph and heterotroph, it is very important to know what carbon is. Carbon is the chemical element of life, it is capable of structuring itself in many ways and establishing bonds with a multitude of chemical elements, in addition, its light weight makes it the perfect element for life. We are all made of carbon and, in one way or another, we need to take it from the environment around us.
Both the words autotroph and heterotroph derive from the Greek. The word "autos" means "by itself," "heteros" is "other," and "trophe" means "nourishment." According to this etymology, we understand that an autotrophic being creates its own food and that a heterotrophic being needs another being to feed itself
Basics of autotrophic and heterotrophic nutrition - Differences and curiosities
Autotrophic nutrition
autotrophs create their own food by fixing carbon, that is, autotrophs get their carbon directly from carbon dioxide (CO2) that forms the air we breathe or dissolved in water, this inorganic carbon they use to create organic carbon compounds to create their own cells. This transformation is carried out through a mechanism called photosynthesis.
Photosynthesis is the process by which green plants and other organisms transform light energy into chemical energy. During photosynthesis, light energy is captured by an organelle called a chloroplast, present in the cells of these organisms, and is used to convert water, carbon dioxide, and other minerals into oxygen and energy-rich organic compounds.
Heterotrophic nutrition
On the other hand, heterotrophic beings obtain their food from organic sources present in their environment, they cannot transform inorganic carbon into organic (proteins, carbohydrates, fats…). This means eating or absorbing materials that have organic carbon (any living thing and its waste, from bacteria to mammals), such as a plant or animal. All animals and fungi are heterotrophs
There are two types of heterotrophs: photoheterotroph and chemoheterotroph Photoheterotrophs use light energy for energy but need organic matter as a source of carbon. Chemoheterotrophs obtain their energy through a chemical reaction that releases energy by breaking apart organic molecules. Because of this, both photoheterotrophic and chemoheterotrophic organisms need to eat living or dead things for energy and to take up organic matter.
In short, the differences between autotrophs and heterotrophs reside in the source they use to obtain food.
Example of autotrophic living beings
- The green plants and algae are autotrophic beings par excellence, specifically photoautotrophs, use light as a source of energy. These organisms are essential to the food chains of all the world's ecosystems.
- Iron bacteria: they are chemoautotrophs, they obtain energy and food from the inorganic substances that exist in their environment. We can find these bacteria in soils and rivers rich in iron.
- Sulfur bacteria: chemoautotrophs, they live in accumulations of pyrite, which is a mineral made of sulfur, on which they feed.
Examples of heterotrophic living beings
- The herbivores, omnivores andcarnivores are all heterotrophs because they feed on other animals and plants.
- Fungi and protozoa: absorb organic carbon from their environment. They are chemoheterotrophs.
- Purple non-sulfur bacteria: are photoheterotrophs that use non-sulfur organic acids for energy, but get carbon from organic matter.
- Heliobacteria: other photoheterotrophs that require sources of organic carbon found in the soil, especially in rice crops.
- Manganese Oxidizing Bacteria: A chemoheterotroph that uses lava rocks for energy, but relies on its environment for carbon organic.
