Charles Robert Darwin, the biologist, the psychologists, philosophist, is the one who put forward the doctrine of biological evolution, which destroys 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.
But 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. 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 competition among animal populations, only those will survive that have properties of benefits under given specific conditions, allowing producing offspring as well. His 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 cannot be found within the population. This variation of features and properties creates the advantage of some organisms over others.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..The core principle of natural selection has the following implications: Organisms have a tendency to overproduce while living space and food are limited, so that creatures must “fight for survival.” Variants exist in individuals within the same population, and individuals with favorable variations that adapt to the environment will survive and multiply offspring, while individuals without favorable variability will be eliminatedHowever The “modern” theory of evolution – the synthetic theory of evolution (STE), based on the synthesis of Darwin’s theory of natural selection with Mendel’s genetics, proves that mutations are the cause of variability – abrupt changes in the hereditary structure of the organism that occur randomly do not solve the problem either.