por The heterotrophic nutrition It is one where the organisms that present it do not have the capacity to produce their own food. Because of this, their energy comes from the intake of organic compounds, such as animal or plant tissues.
For example, a rabbit that eats lettuce has this type of nutrition, since it takes food from external sources. Like a lion eating a gazelle. On the contrary, plants and algae, among other organisms, are autotrophs, since they can produce their own food.
In this sense, heterotrophs obtain nutrients when the elements consumed are processed and converted into simpler substances. These are absorbed by the organism and used in the different metabolic processes.
The source of energy in heterotrophic nutrition is varied. Thus, living beings that consume solid and liquid compounds are called holozoic and those that feed on decomposing matter are known as saprophytes. There are also parasites, which live at the expense of the host.
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Characteristics
Consumers
Organisms with heterotrophic nutrition do not make their food. In the trophic chain, they are classified as consumers, since all the energy for carrying out vital processes comes from the intake of food, whether of vegetable or animal origin.
Thus, the primary consumers, such as the rabbit and the cow, feed directly from the producers, represented by the plants. As for the secondary consumers, also called carnivores, they hunt and consume the primary consumers or herbivores.
specialized bodies
Evolutionarily, animals that have heterotrophic nutrition have undergone anatomical and morphological modifications that have allowed them to adapt to the various diets they consume.
These can include anything from soft vegetables, like lettuce and grass, to turtle shells and bones. Also, there are variations in the proportions of fiber, fat and protein content.
For example, in the gorilla, the lower jaw protrudes above the upper, which is known as mandibular prognathism. In addition, it has a very pronounced sagittal crest on its skull. These bony particularities serve as the basis for the strong musculature that is associated with the jaw, which allows it to cut, grind and crush its food.
Another morphological variation occurs in the stomach. In ruminant animals, such as sheep, cattle, deer and goats, the stomach has four divisions: the rumen, reticulum, omasum and abomasum. As for humans, among others, it has only one abdominal cavity.
seasonal variations
In heterotrophic nutrition, there are various food sources. There are animals that eat vegetables (herbivores), others hunt and consume animals (carnivores) and others that can eat both (omnivores).
However, the diet of heterotrophs is influenced by several factors, including the abundance of food and seasonal variations.
This is evident in squirrels, which base their diet on nuts. However, in the spring season the diet undergoes modifications. At that time, the nuts that this animal buried to consume them in the winter, are beginning to germinate. Because of this you cannot consume them.
This causes it to change its diet during that season of the year and consume mainly the fresh shoots of the trees.
Importance
Some of the living beings that have heterotrophic nutrition play a very important role in nature. In relation to this, saprophytic fungi contribute to the degradation of dead matter into simpler elements.
This makes it easier for plants that are close to these fungi to more easily absorb the degraded nutrients.
Other organisms that contribute to the ecosystem are saprophytic bacteria. These are known as the largest decomposers in nature, due to their action on a wide variety of materials.
Man also uses this great degradation capacity of bacteria to his advantage. Thus, he uses them to decompose organic matter and turn it into manure, which is then used as fertilizer to promote plant growth.
Stages of heterotrophic nutrition
– Ingestion
Ingestion is the process of introducing food into the digestive system. In the event that the bite of food is less than one molecule, the most accurate term to describe the feeding action is absorption.
There are two types, microphage ingestion, which is carried out by animals that feed on liquids, such as some parasites, and by those that filter microorganisms. The other type is ingestion is macrophage, where the animal selects the food to eat.
– Digestion
In this phase of heterotrophic nutrition, ingested food is processed by specialized organs. These transform them into simpler substances, using various enzymes and, in some cases, some microbes.
– Absorption
Absorption allows the nutrients produced by digestion, together with mineral salts, water and vitamins, to be transported from the organs of the digestive system to the cells.
– Excretion
In this last stage, the unusable substances can become toxic elements, so they need to be excreted abroad. In this way, the homeostatic balance in the body is maintained.
Guys
– Holozoic nutrition
Holozoic nutrition is one where the living being ingests liquid and solid food, which is processed in the digestive system. In this way, the organic material is broken down into simpler molecules, which the organism assimilates.
For example, the proteins contained in meat are converted into amino acids, which become part of the body’s cells. After this process, where the nutritive substances, including water, were extracted, the remaining particles are excreted.
This type of heterotrophic nutrition is typical of humans, animals, and some unicellular organisms, such as amoeba.
Taking into account the origin of the food consumed, the organisms that present this way of nutrition are divided into:
herbivores
The animals that make up this group feed mainly on plants. Within the trophic chain, they are considered as primary consumers. Also, depending on the type of plant source they consume, they can be classified in various ways.
Thus, those whose diet is based mainly on fruits are called frugivores, while those specialized in leaves are known as folivores or browsers. Animals that feed on wood are called xylophages and those that eat mainly seeds are granivores.
Within the group of herbivores are cows, rabbits, giraffes, deer, sheep, pandas, hippos, elephants and llamas, among others.
Carnivores
The carnivorous animal obtains energy and all nutritional requirements through the consumption of meat, either through predation or by consumption of carrion. In some cases it can subsist exclusively on a meat-based diet, which is why it is considered a strict or true carnivore.
However, you may occasionally consume small amounts of vegetables, but your digestive system is not able to digest them efficiently. Within this group are the lion, the hyena, the tiger, the coyote and the eagle.
These secondary consumers can be grouped taking into account the kind of prey they consume. Thus, those who eat insects are known as insectivores or entomophages.
It is even possible to be even more specific, since animals specialized in consuming termites and ants, such as the anteater, are called myrmecophages.
omnivores
Animals that feed on both plants and animals belong to this group. They are generalists and opportunists, whose digestive tract can process plant material and meat, although it is not specifically adapted to efficiently process some of the components present in both diets.
Some examples of this group are the human being, the pig, the crow, the raccoon, the piranha and the bears, except the polar bear and the panda bear.
– Saprophytic nutrition
Saprophytic nutrition is one where the food source is dead and decaying organisms. From these, they obtain the energy to carry out their vital functions. Within this group are fungi and some bacteria.
To carry out the degradation of the ingested material, the saprophytes release some enzymes, which act on the complex molecules and convert them into simpler elements. These molecules are absorbed and used as a source of nutritional energy.
This type of nutrition requires some special conditions for it to occur efficiently. Among these are a humid environment and the presence of oxygen, although yeast does not need this to carry out their food metabolisms.
In addition, the pH of the medium where it is located must be neutral or slightly acid and the temperature warm.
– Parasitic nutrition
In parasitic nutrition, the organisms inhabit the body of the hosts and live at the expense of it. Although the parasite feeds at the host’s expense, the host derives no benefit from this relationship. Otherwise, they are generally harmed, and can even cause their death.
Some examples of these living beings are the tapeworm, the louse, the tick, the flea and the bedbug, among others. Depending on the place it occupies in the host, parasitic nutrition can be divided into:
-Ectoparasites, are those that inhabit the external part of the host’s body, as occurs with the flea.
-Endoparasites, which live inside the host’s body, such as tapeworms or tapeworms.
-Mesoparasites. A clear example of this type of parasite is the copepods. These crustaceans are usually partially inserted in the different body tissues of the host.
Examples of living beings with heterotrophic nutrition
Examples of living beings with heterotrophic nutrition are carnivores, herbivores, omnivores, organisms from the kingdom fungi and protozoa (they need carbon to survive and reproduce), heliobacteria (they need carbon),
Cymothoa meager
This crustacean is a parasite that attaches itself to the tongue of its host fish, the marine fish Lithognathus. It does this using the three pairs of front legs it has. In this way, it can feed on the blood that comes from the artery found in this organ.
Over time, the fish’s tongue atrophies and falls off. Given this, the body of the crustacean replaces the organ of the fish, which does not see any of its nutritional functions altered as a result of this.
mucor mucedo
This saprophytic fungus develops in the soil and causes rotting of fruits and insects. This species gets…