Charles Robert Darwin (February 12, 1809 – April 19, 1882) put forward the doctrine of biological evolution, thus destroying all kinds of idealistic theology and species invariance. In addition to biology , his theory also focused on the development of anthropology, psychology and philosophy.
The idea of a gradual and continuous change in all species of plants and animals was expressed by many scientists long before Darwin. It was Darwin who put forward a completely new hypothesis regarding living nature, generalizing individual evolutionary ideas into one, the so-called theory of evolution , which was the most widely spread in the world.
The richest empirical material accumulated by that time in geography, archeology, paleontology, physiology, taxonomy, etc., allowed Darwin to draw a conclusion about the long evolution of wildlife. Darwin expounded his concept in his work “The Origin of Species by Natural Selection ” (1859).
It should be noted that despite the huge popularity among the reading public, the idea of a gradual appearance in the living nature of new species for the scientific community of the time turned out to be so unusual that it was not accepted immediately.
Darwin suggested that in animal populations there is competition, only those individuals survive that have properties of benefits under given specific conditions, allowing to leave offspring. Darwin’s evolutionary theory is based on three principles: a) heredity and variability; b) the struggle for existence; c) natural selection. Variability is an inalienable property of all living things. Despite the similarity of living organisms of the same species, two completely identical individuals can not be found within the population. This variation of features and properties creates the advantage of some organisms over others.
Under normal conditions, the difference in properties remains invisible and does not have a significant effect on the development of organisms, however, under changing conditions, especially in the unfavorable direction, even the smallest difference can give one organisms a significant advantage over others. Only individuals with the appropriate conditions of the properties are able to survive and leave offspring. Darwin distinguishes between uncertain and definite variability.
A certain variability , or adaptive modification, is the ability of individuals of one species to react in an identical way to changes in the environment. Such group changes are not inherited, so they can not supply material for evolution..
Development of Darwinian evolutionary theory
In 1865 Austrian botanist GJ Mendel from the pea hybridization experiment obtained the correct conclusion of the genetic particles. He proved that the genetic material is not fused, separation and recombination can occur during the passage of reproduction. At the beginning of the 20th century, genetics was established. Thor Morgan and others then established the theory of chromosome genetics, revealing the basic laws of inheritance. This should remedy the shortcomings of Darwin’s theory and contribute to the development of evolution; but at that time most of the geneticists, including Morgan , were opposed to Darwin’s theory of natural selection. People ‘s belief in Darwin’s theory of evolution , a serious crisis.