What is AMENSALISM: Definition and Examples

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When defining the relationships that are established between the different species of living beings, we define a series of concepts that allow us to classify and study them. Perhaps the best known to the general public are competition, parasitism or symbiosis, but there are others such as commensalism, mutualism or amensalism that are usually known by people more specialized in these areas. In this Green Ecologist article we will define what is amensalism and some examples of it.

What is amensalism: definition

Amensalism, also known as antagonism, is the biological interaction, that is, between living beings, in which one of the members involved does not experience any alteration but prevents the development and survival of the other. In other words, the amensalism relationship it takes place when a smaller or weaker species establishes an interaction with another stronger or larger species in which it is harmed, while the dominant one does not notice the existence of the other. Amensalism is important for studying trophic chains or relationships within ecosystems, such as predator-prey relationships. It also helps to understand the impacts of pests on agriculture or the growth of certain plants and species in that environment.

Normally, the way in which amensalism or antagonism takes place is that of the production of toxic substances by one of the members involved and that prevents other populations from developing or subsisting while they are around them. This interaction is very common within microorganisms.

As soon as an organism occupies a habitat, its survival instinct makes it do everything possible to prevent other species from surviving or living there. This interaction is not defined as positive for the organism, rather neutral and detrimental to species that are displaced.

In this other Green Ecologist article we talk extensively about interspecific relationships: types and examples.

Difference between amensalism and competition

Frequently, some relationships between species can be confused with others because of their similarity and this can be the case between amensalism and competition. The competition is a biological interaction in which a fight between two organizations to obtain the same resources, which both need to meet their needs.

Therefore, competition is a relationship in which the convenience of one body necessarily implies the detriment of the other, while in amensalism one of the organisms does not derive any benefit from the action, that is to say, it can be neutral or harmful to the organism that is displaced.

Amensalism: examples

Can be identified amensalism relationships in all groups of living beings. Let's see some how examples of amensalism:

Mushrooms

Since fungi do not photosynthesize, they must absorb simple and soluble nutrients from the environment. Because these nutrients are absorbed by the fungi in the environment, they are no longer available to other populations, therefore, they can compromise the existence of other species in the environment.

When a fungus interacts with another species it can secrete a chemical component of its metabolism that harms the other species. This occurs, for example, in the fungus Penicilium notatum, which secretes a substance capable of destroying many bacteria, penicillin. Penicillin was discovered by Alexander Fleming and is one of the most widely used antibiotics in the world. The relationship that this fungus establishes with the bacteria it inhibits is amensalism.

Plants

Among plants, an example of amensalism relationship is that of the American black walnut (Juglans nigra), which you will see in the image below, which produces a toxin known as juglone and which prevents the growth of other plants around it. This substance deprives other plants of the energy they need for photosynthesis and eventually causes their death, thus reducing competition for survival. Juglona is produced mainly in the buds, roots and hulls of the fruits.

There are planktonic algae that release a toxic substance, forming red spots in the ocean and that cause the death of marine animals or the leaves of pine trees that fall to the ground, which release a substance that prevents the germination of the seeds of other plants.

Animals

For example, some wild pigs when they are transferred to other habitats eat all the nutrients in their path and excrete their waste to wetlands, rivers or soils, polluting them and causing the death of many species and damage to agriculture. Another clear example occurred when rabbits were introduced to Australia for hunters, and it turns out that they ended up becoming a pest that makes it difficult for other species to exist. Another common example is when animals trample the grasses without using them at all, in many cases killing them.

If you want to read more articles similar to What is amensalism and examples, we recommend that you enter our Biology category.

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