What is symbiosis in ecology and biology
We can define symbiosis as the close relationship of coexistence established at an ecological level between two individuals of different species that are in direct contact with each other in order to obtain a benefit from this union.
These two organisms involved are called ” symbionts ” or, if they are of different sizes, the larger one is called the host and the smallest symbiote. These relations were named as such for the first time by the German botanist Heinrich Anton de Bary in 1879.
Symbiotic relationships can be classified according to several factors, such as, for example, how the relationship of symbiosis between the two individuals is, which is sometimes essential for life. By this, we mean that not in all cases the two species benefit. There are relationships in which only one of them benefits, and may be harmful to the other. We’ll tell you then.
Depending on the costs and benefits obtained by the species involved, we can distinguish between:
- Mutualism: it is usually used as a synonym of symbiosis, although it is not exactly the same. Mutualistic relations are those in which the two organizations involved obtain benefits.
- Commensalism: unusual in nature, one of the species benefits from the other, although they do not get to harm because it does not pose any problem to the species “host”.
- Parasitism: one of the species, called a parasite, benefits at the expense of the other, the host species, but, in this case, it does harm. An example is the parasites that affect plants.
Considering how is the spatial relationship between the two symbiont organisms, that is, if one of the symbionts lives inside or not the other, we can distinguish between:
- Endosymbiosis: if the organism lives inside the cells of the other symbiont or in the gaps between them.
- Ectosymbiosis: if the symbiote can survive on the outside of the other, that is, outside its cells, it can be found on the surface of the digestive tract, exocrine glands or externally on your body.
As we mentioned, some of these relationships are indispensable for life. For this reason, they can again be classified according to whether they are temporary (optional) or permanent (obligatory) relationships.
Finally, according to the way in which this relationship has been established, it is possible to distinguish between the symbiotic relationships of vertical transmission , when the symbionts are transmitted to the offspring, or the symbiotic relationships of horizontal transmission , when the host organism obtains its symbiont from the environment generation after generation.
Examples of symbiosis
As will be clearer through the examples, symbiosis relationships are very important in the environment , as they enable many species to survive. That is why we believe that symbiosis works as an enhancer of the evolution of these species, which manage to improve their way of life by establishing relationships with other organisms and species.
The examples are very numerous and varied. Next, we present some examples of symbiosis in ecology and biology so that, in this way, the importance that these types of relationship suppose for the survival of these organisms becomes clearer.
- Ants and aphids: some species of ants, such as the black ant ( Lasius niger ), protect herds of aphids that in turn provide them with food and molasses, a sugary substance they produce rich in carbohydrates. In the main image of this article, we can see this same example.
- Ants and acacias: other species of ants such as Pseudomyrmex ferruginea protect acacias from other parasites or herbivores. In return, the tree provides shelter and food.
- Crocodiles and plovers: it is by all known the great power that the crocodiles possess in the jaws. These present no less than 80 teeth, which replace 2 or 3 times a year and the remains of food can cause serious problems such as infections. Thus arises the relationship with the Egyptian plovers. They obtain their food by cleaning the remains they find between the teeth of the crocodiles and these thus avoid oral problems allowing them to move inside their mouths.
- Sharks and remoras: this is the clearest case of commensalism. Surely you have seen other sharks under the sharks. They adhere to the sharks and obtain from them protection and food from the remains of food that do not ingest them. For sharks, the presence of remora is practically indifferent.
- Goby fish and blind prawn: the shrimp, despite its lack of vision, digs the burrow that keeps it clean and allows the fish to share so that it acts as their guide for the search for food and, in addition, warns of the dangers that they lurk through movements of its tail that create vibrations that the shrimp is capable of detecting, at which time both can hide in the burrow.
- The clownfish and the anemone: these fish make their whole lives inside the anemones, which are very poisonous. They establish a mutualistic relationship in which the clownfish attracts other predatory fish that, when they come in contact with the anemone, are paralyzed and serve as food, the remains of which are used by the clownfish.
- Lichens: are the symbiotic association between a fungus and algae. The fungus protects the algae from dehydration and provides a structure to grow on, and the algae make carbohydrates that the fungus can use as food. There is a great variety of lichens since they are very resistant and capable of colonizing very diverse environments.
- Mycorrhizae: Mycorrhizae are fungi that establish symbiotic relationships with multiple plant species of vascular plants. How? The roots of these plants secrete useful substances for these fungi and these, in turn, make materials found in the soil as minerals and other materials in decomposition are more assimilable by plants.
- Intestinal flora and microbiota: in our intestine, as in many other parts of our body, there is a large number of bacteria and other microorganisms that live in symbiosis with our cells and that are of great importance to our health to such an extent that variations in this microbiota can cause alterations in our body.
Now that you know well what is the symbiosis in ecology and biology and have seen several examples, you may also be interested in knowing with this other Green Ecology article the interspecific relationships: types and examples