Heterotroph Examples

Heterotrophs uses organic carbon for growth. They cannot produce organic compounds from inorganic sources. They contrast with autotrophs like plants and algae, which can produce their own food and use inorganic carbon for growth. Heterotrophs cannot produce their own food. More than 95% of all living organisms are heterotrophic, which includes all animals, fungi, and most bacteria and protists. They depend on autotrophs and other heterotrophs for food and energy. They are placed on the second level of the food chain.

There are two types of heterotrophs: photoheterotroph and chemoheterotroph. The first uses light for energy but not carbon dioxide for their carbon source, but must rely on compounds such as carbohydrates, fatty acids, and alcohol (non-sulfuric bacteria, etc.). The chemoheterotroph get their energy by oxidation of preformed organic compounds. They consume other living or dead organisms such as animals, fungi, bacteria, and nearly all pathogens. In short, photoheterotroph obtain energy through light, and chemoheterotroph uses chemical energy.

1. Herbivores, omnivores, and carnivores: All are examples of heterotroph because they eat other organisms to get proteins and energy. They cannot produce their own food or energy.

2. Fungi and protozoa: Since they require carbon to survive and reproduce they are chemoheterotroph.

3. Non-sulfur bacteria: A photoheterotroph using organic acids and not hydrogen sulphide. There are purple and green non-sulfur bacteria. The purple uses hydrogen and make up a variety of separate groups. Relatives include non-photosynthetic proteobacteria. There is no oxygen byproduct. They may also be related to the mitochondria (symbiotic bacteria) acting as organelles in plant and animal cells. The green is a type of chlorobacteria and uses light for photosynthesis.

4. Heliobacteria: Another photoheterotroph requiring organic carbon sources found in soils, and more abundant in water-saturated soils. They are anaerobic and are useful in the fertility of paddy fields.

5. Manganese-oxidizing bacteria: A chemohetrotroph using igneous lava rocks. It is much rarer than iron in oceanic crust and not as much is known. However, it is much easier for bacteria to extract from igneous glass.