For those who do not know what convergence is in biology, it should be clarified that this concept came to us from the Latin language and it means “rapprochement”. It should be noted that this definition is used not only in biology, but also in linguistics, telecommunications, and even in political science. That is why it should be understood that convergence is a certain similarity of characteristics in organisms that are dissimilar in nature, which arose in the context of evolution. As a result of this process, they have a certain number of similar symptoms (for example, the appearance, structure of organs).
Many people know that through convergence, for example, streamlined sharks, dolphins, flying membranes in marsupial squirrels and flying squirrels arose. If we talk about the evolutionary form of groups of living organisms, then we can distinguish convergence and divergence, as well as parallelism.
Irreversibility of the evolutionary process
In the process of evolution, each organism went through certain stages in its development, and this applied to absolutely all structural components. And if convergence is a "similarity", then it is worth considering in depth other concepts.
1. Divergence - these are the differences of signs that exist within a particular species. This biological process leads to the emergence of new groups and individuals. The more pronounced the divergence, the more differences any particular form takes, as a result of which the organisms begin to differ not only in their appearance, but also in their internal structure, in the habitat and in the features of the choice of space for existence. And only those who can survive in the environment can choose one area. Due to the fact that the key concept of evolution is natural selection, only the strongest species survive, and the weaker ones die.
2. Convergence is, first of all, a phenomenon opposite to divergence. In this case, various organisms begin to acquire similar forms. This is often associated with the same habitat, its basic conditions and characteristics. It is worth noting that the phenomenon of convergence is most common in the animal world, where, for example, birds cannot do without wings, the fish should have a streamlined shape, and so on.
3. Concurrency - in translation from Greek, this concept means "nearby." This development in the context of the evolution of similar groups that are genetically close, but the acquisition of similar traits in these representatives is not dependent on each other. Almost always, these traits are inherited from their ancestors. Considering that convergence is similar features that gradually appear with a certain dependence, parallelism is directly determined by the historical process (in particular, we are talking about phylogenesis).
Why do convergent phenomena occur?
When considering the basic concepts in the context of evolution, it was already said that convergence is a frequent phenomenon that is inherent mainly to representatives of the animal world. Naturally, both divergence and parallelism are often found in nature. But the need for convergence cannot be denied, because the reasons for the occurrence of such similarities are not determined by the presence of kinship, but by a certain set of characteristics that needed to be developed in the evolutionary process so that this or that type of living organism survives and becomes stronger.
So, the main reason for convergence is the direct similarity of ecological niches in which certain representatives of the animal world live. If you look at the most popular examples of convergent similarities, you can understand why certain types of representatives of living organisms have a specific shape, appearance and certain lifestyle features.