Classification and systematics is an independent branch of biology, which develops the principles of dividing living organisms into certain groups according to external signs and structural features of their organisms. In common people, the word “animals” usually means mammals, not including birds, fish, insects, etc. In biology, there are 5 kingdoms of living organisms: the kingdom of Bacteria, the kingdom of Protozoa, the kingdom of Mushrooms, the kingdom of Plants and the kingdom of Animals . Animals differ from other organisms in heterotrophic nutrition and a mobile lifestyle.
The classification of the animal world is structured in such a way that each of its representatives has a type, class, order, family, genus and species.
Types were introduced into science by the French zoologist Georges Cuvier in the early nineteenth century. The classification of animals proposed by the scientist contained four types: vertebrates, mollusks, segmented and radiant. Today there are more than ten types of animals, the most voluminous and common of them are chordates.
The classification of animals includes their division into five classes: fish, birds, amphibians, reptiles and mammals. The criteria for assigning a living organism to a particular class are its appearance and certain signs of the structure and functioning of organs and systems. So, for example, fish have a single-chamber heart, reptiles have a three-chamber, and mammals have a four-chamber with the division of blood into arterial and venous. In nature, classes of animals appeared in the exact order in which they are called here: the first were fish, and the most perfect organisms were mammals, led by humans.
Further, the classification of animals suggests dividing each class into several orders. For example, there are a clan of artiodactyls, a detachment of artiodactyls, and a detachment of carnivores. In plant taxonomy, a similar taxon is called not a detachment, but an order.
The family unites representatives who are as similar to each other and have a common ancestor. For example, the cat family includes a cat, lynx, tiger, lion, jaguar, leopard, snow leopard, ocelot, etc. The canine family combines a wolf, a coyote, a dog, a fox, etc.
A family follows a family, and a species follows a family. A view is the smallest unit of taxonomy. The criterion for isolating the totality of individuals into a single species is their ability to interbreed and produce prolific offspring. Sometimes biologists talk about the existence of another trait that allows recognizing the totality of individuals as a single species: they must live within a certain area. However, this attribute is formal; isolation of one individual from the rest does not stop its belonging to their species. Separating this trait, scientists wanted to say that when living individuals of the species in different parts of the globe, its reproduction would be difficult. Mating individuals of various species often leads to the birth of hybrids, but such hybrids are no longer able to reproduce their own kind.
Animals are classified by assigning a name to each new species and determining its belonging to taxa according to morphological and genetic characteristics. The name of the species is written in Latin, so that it is more convenient for scientists from different countries to work on the study of its populations.
In biology, there are alternative taxonomy options. Philosophers and biologists have repeatedly discussed the classification of animals presented by Borges. He does not have a scheme for dividing animals into groups, but an exhaustive list of the groups themselves is presented. Borges writes that according to the Chinese encyclopedia, all animals are divided into tame; owned by the Emperor; sirens; fabulous; countless; running like crazy; stray dogs; embalmed; similar from afar to flies; milk pigs; smashed a flower vase; drawn with the finest brush made of camel hair; included in the classification; others. This classification of animals is strange and incomprehensible, it is not recognized by science.