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Diversity of the living beings

 

The most superficial examination on the alive beings allows us to observe that they present great variations in all the aspects, size, structure... By all it must have a system to name them and to identify them.

The taxonomy is a branch of the botany and the zoology that is in charge of the classification and nomenclature of the alive beings of such form that the related alive beings between if they are placed in a same group. The taxonomist must consider at the time of applying a name to an alive being and assuring that he has applied it correctly: that the used name has not been used previously, must describe to that alive being with the greater number of possible data so that another taxonomist can identify it later, finally he must place the organism within a classification or a group with which he has well-known or supposed relations.

The system to give name to the alive beings has arisen throughout the centuries based on a developed method.

Aristotle (384-322 a.c.) it classified to the species animals that knew themselves in their time being based on the external characteristics of the animals. This system remained until century XVIII. Aristotle distinguished two groups: animals provided with blood and lacking animals of blood. This distribution in broad strokes corresponded to the present classification in vertebrates and invertebrates. These studies became serious with Linnaeus (1707-1778) which in their work of the tenth edition "Natural System" then makes the classification of 8500 plants and 4236 well-known animals. As far as the animals it made two groups: "vertebrata" that included four classes and "invertebrata" that included two classes. The four classes would be the two Mamalia, birds, anfibea and pisces whereas insecta and verms. As for the vertebrata the classification keeps similarities with the present one. At the same time Lamarck (1744-1829) being based on the classification of Linnaeus it subdivided to the invertebrata in 10 classes, other authors made other classifications until reaching the present one. Nowadays in the kingdom animal 28 types are included, being the different opinion of classification depending on the authors. In the vegetal kingdom 24 sistémicas units exist. In the work of Linnaeus a scientific name was applied to the organisms that it identified. The scientific name consisted of two Latin words or latinics of which first it is the name of first generate and the second name of the species, appears the binomial nomenclature. Linnaeus thought that a species is determining to be alive that has been created of separated form by a supernatural power and that had characteristics that differentiated it from the others. To the similar species it grouped them in only a sort, to the similar sorts grouped them in orders, classes and the classes within a kingdom. Scientific names are used front to the common ones, since these can have meaning different according to the country and by the tendency from the universality of the scientists. With the passage of time it appears a great diversity of animals and plants as well as a great transmitted diversity of caractéres to the descendants. The taxonomists began to understand that the species are not created single nor isolated but that they are the result in the inheritance within a same common trunk.

Taxon is defined, "taxon smaller is the one of species", the species is a population or group of populations formed by individuals in its natural habitat and with real or potential capacity to cross itself, defines the sort like the group of species that have narrow ancestral relations but that they are not able to cross itself between if (except for exceptions). The sorts are grouped in families, the families in orders, the orders in classes, the classes in phylum and these in kingdom.

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