The final answer to a question how many exists in the world of animal species while is not present. In spite of the fact that the science biology costs at a high step of development today, and more than 1.7 million types of organisms are already described, it is not a limit – scientists assume that the exact quantity approaches figure of 8.7 million and if to consider also the died-out types, then about 500 million will turn out.
What is a look?Species – the main structural unit of classification of living organisms on Earth. It describes group of the individuals having uniform morphological, physiological, biochemical, behavioural and other features. Organisms of one look are capable to be crossed among themselves, giving posterity, capable to reproduction, – between different types it is impossible. Under the influence of evolutionary factors, in the changing environmental conditions the types can be divided.
Bases of specific systematization of living organisms were offered by the Swedish scientist Karl Linney in the middle of the 18th century. Since then more than million different types were found and studied.
Animals are a group of organisms which make the biological kingdom. They are eukariota, that is their cages consist of kernels. Animals differ in heterotrophic food (emit energy from organic compounds), ability to active movement. In a spoken language animals often call land vertebrata, but in terms of science it is set of many classes: fishes, insects, birds, starfishes, worms, arachnoid and others.
Quantity of animal speciesNot only exact, but also even the approximate quantity of types of the living organisms living on Earth is unknown. Some biologists speak about small gaps in systematization of living beings which can be replenished with only several hundred more thousands of types, others claim that unknown and undescribed are millions of different types living in the most inaccessible to the person places. The biggest number given by researchers makes 8.7 million. Until about 1.7 million types are described, animals among them make the most part: about hundred thousand types are the share of plants, mushrooms and other kingdoms. So, about 5.5 thousand mammals, 10.1 thousand birds, 9.4 thousand reptiles, 6.8 Amphibia, 102 thousand of arachnoid are studied. Insects remain the most numerous group so far – them there are about one million.
It is supposed, as among the types which are not studied still the insects make the most most part – about ten million.
Despite development of biology to study and find new types still quite difficult. If among large mammals big replenishments are not expected, then it is more difficult to investigate smaller animals. Though still annually scientists find several dozen new species of mammals. Birds are also quite well studied: it is easy to find them and it is pleasant to watch them. There are situations when biologists find living representatives of types who were considered as the dead long ago. Thus, the science still should give the answer to a question of exact quantity of animal species.