Cats and dogs are animals of different species, and this is nothing new for any person, as they are very different beings. However, it is not just appearance that determines whether or not individuals are of the same species. Several factors are used to indicate a species and they are not always very clear, making it difficult to define this concept.
→ What is a species?
There are more than twenty published species concepts, however, currently, the best known definition is the one proposed by Mayr, called biological species concept. According to this concept, species are groupings of natural populations that are able to reproduce naturally and are reproductively isolated from other groups.
This means that, for organisms to be considered of the same species, they must be able to reproduce in a natural environment. Realize that in no time appearance is used as the decisive criterion. One of the reasons that the appearance is not used for this purpose is the existence of those species that have males and quite distinct females, such as the parrot-ecletus, in which the male has green plumage and the female has red plumage and blue. Also, there are many very similar species that are incapable of breeding.
→ What are the problems with the biological species concept?
Although the biological concept of species is well accepted, it does have some problems.. One of them is the fact that it does not include asexual organisms. If an organism reproduces itself, how can we analyze its ability to reproduce with another individual?
In addition to asexual reproduction, we cannot forget about hybrids. This term is used to explain the result of the crossing between two different species. Crossing a mare with a donkey, for example, gives rise to a donkey or a mule. Therefore, individuals capable of reproducing are not always of the same species..
The biological species concept is also a problem when we talk about fossils. In these groups of organisms, it is impossible to determine the reproductive process.
→ Other species concepts
We realized that there are many problems to define a species, and there is no consensus on the part of researchers regarding these definitions. Thus, there are other concepts that seek to correct existing flaws in the biological concept.
Morphological species concept: This concept defines a species by its similarity. Although imprecise, it is important for identifying asexually reproducing organisms.
Ecological species concept: In this concept, a species is defined by analyzing its ecological niche.
Phylogenetic species concept: This concept defines a species as the smallest group of individuals that has a common ancestor. To make this statement, it is necessary, among other analyses, to observe morphology and molecular sequences.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-especie.htm
