Heterotrophic organisms

The heterotrophic organisms are those that must be fed with the organic substances that are synthesized by other organisms, either beings autotrophic or heterotrophic at the same time. To this group belong all the members of the animal kingdom , fungi , a large part of bacteria and archaea .

Characteristics of heterotrophic organisms

The main characteristics of heterotrophic organisms are the following:

• They cannot synthesize their own food.
• They depend on autotrophic organisms or other heterotrophs to live and feed.
• They degrade food to produce energy .
• They are organisms dependent on others.

Source

Life on earth has its origins 3.5 billion years ago. In this period, the atmosphere was composed of hydrogen, water, ammonia and methylene and there was no oxygen. A possible proposal explains the union of molecules to be able to form complex compounds , and carry out metabolic processes . This created the first cells, specifically heterotrophs.

The heterotrophs were not able to produce their own source of energy and food, so they had to consume other organisms from the hot soup described by Haldane .

The heterotrophic hypothesis is a proposal from the branch of evolutionary biology that tells us that the first living organisms were heterotrophs. This heterotrophic hypothesis was first mentioned by scientist Charles Darwin in one of his letters with JD Hooker.

What are heterotrophic organisms

Heterotrophic organisms are the animals or organisms that are capable of obtaining the different nutrients they need from other organisms. They are the animals , the fungi , the beings protists and most of the bacteria that exist and the need to feed on other animals, usually known by the name of consumers .

Types

The types of heterotrophic organisms are as follows:

• Herbivores : They feed mainly on plants and are very diverse, from small insects to large mammals such as elephants. They are considered the primary consumers of the food chain.
• Carnivores : they are living beings that feed on the meat of other animals. They belong to the ” carnivorous ” order, although there are also carnivorous plants. They are called predators and the organisms that carnivores hunt are called prey.
• Omnivores : they consume a wide variety of foods, including plants , animals , algae, and fungi, and their size ranges from small insects to large mammals. Some mammals are omnivores.
• Detritivores :  heterotrophs that feed on organic matter called detritus , which are the decomposed parts of plants and animals, as well as fecal matter. They get rid of decomposing organic matter.
• Decomposers : they recycle nutrients through decomposition . They are capable of absorbing nutrients directly through biochemical processes that allow them to break down matter without ingesting it.
• Scavengers – They consume decomposing biomass , such as meat or plants. Many are carnivores , but generally consume animals that have died of natural causes or have been killed by another predatory carnivore.

Nutrition

Nutrition is obtained through the digestion of organic compounds . Heterotrophic organisms must acquire and absorb all the organic substances they need to survive. All heterotrophs (except intestinal parasites) have to convert solid food into soluble compounds capable of being absorbed through digestion . When the soluble products of digestion in the body are assimilated they are broken down for the release of energy. All heterotrophs depend on autotrophs for their nutrition .

The three main types of heterotrophic nutrition are:

• Holozoic nutrition : Complex foods reach a specialized digestive system and break down into small pieces to be absorbed. It has 5 stages, ingestion , digestion , absorption , assimilation and elimination .
• Saproobic nutrition : organisms feed on the organic remains of other organisms. For example: decomposers.
• Parasitic nutrition : organisms obtain food from the host , and the host receives no benefit from the parasite. When there is a parasite inside the host’s body, it is known as an endoparasite .
• Symbiotic Nutrition : Certain plants live in close association with other plants for long periods and share and shelter.

Energy

Living beings can only maintain their activity through an exchange of matter and energy with the environment that surrounds them. This flow begins with energy from the sun and photosynthesis . In the case of heterotrophic organisms, this energy transfer occurs through a series of organisms which feed on the previous one and are, in turn, food for the next one.

Importance of heterotrophic organisms

Heterotrophic beings are found in greater numbers on planet Earth as the term applies to all animal species, including humans . Heterotrophic beings are important because they can occupy the second, third and fourth links in the food chain .

Heterotrophic animals are also important because they are the ones that manage to maintain an adequate balance in the food chain, controlling the volume of plant and animal species.

Examples

Some examples of heterotrophic organisms are as follows:

• Goats, cows and ruminant animals which have an exclusively vegetarian diet , from which they take what they need to survive and build their own tissues.
• Lions, tigers, large feline predators that form the group that eats meat from the animal kingdom and that need to hunt to consume the necessary nutrients to start their own metabolism.
• Fish, eels and rays that are the predators of the underwater animal kingdom that must consume other smaller living beings to stay alive.
• Whales and other marine mammals : some prey on small fish ; others feed on plankton . Both require the consumption and digestion of these living beings to extract the necessary nutrients for life.
• Carnivorous plants that have organs specifically adapted to the digestion of small insects that, attracted by the sweetness of their aromas.
• The birds that can feed on insects and worms , the fruits of the trees or leaves, floral nectar, fish and small rodents . of the ingestion and assimilation of matter coming from other living beings to live.