Accessible evolution for shared development
Evolution is a natural process of the development of life on Earth.
Evolution is a process of neontogenetic development, a single-level qualitative transformation and / or degradation, a process of structural change of something from one state to another.
Biological evolution (from lat. Evolutio - “deployment”) is a natural process of development of wildlife, accompanied by a change in the genetic composition of populations, the formation of adaptations, speciation and extinction of species, the transformation of ecosystems and the biosphere as a whole.
There are several evolutionary theories that explain the underlying mechanisms of evolutionary processes. At the moment, the generally accepted is the synthetic theory of evolution (STE), which is a synthesis of classical Darwinism and population genetics. STE allows us to explain the relationship between the material of evolution (genetic mutations) and the mechanism of evolution (natural selection). In the framework of STE, evolution is defined as the process of changing the frequencies of gene alleles in populations of organisms over a period exceeding the life expectancy of one generation.
Charles Darwin was the first to formulate the theory of evolution through natural selection. Evolution through natural selection is a process that follows from three facts about populations: 1) more offspring are born than they can survive; 2) different organisms have different traits, which leads to differences in survival and probability of leaving offspring; 3) these traits are inherited. These conditions lead to the appearance of intraspecific competition and selective elimination of individuals least adapted to the environment, which leads to an increase in the share of such individuals in the next generation whose traits contribute to survival and reproduction in this environment. Natural selection is the only known cause of adaptations, but not the only reason for evolution. Non-adaptive causes include genetic drift, gene flow, and mutations.
Despite the ambiguous perception in society, evolution as a natural process is a firmly established scientific fact, has a huge amount of evidence and is not in doubt in the scientific community. At the same time, certain aspects of theories explaining the mechanisms of evolution are the subject of scientific discussions. Discoveries in evolutionary biology had a huge impact not only on traditional areas of biology, but also on other academic disciplines, for example, anthropology, psychology. Ideas about evolution have become the basis of modern concepts of agriculture, environmental protection, are widely used in medicine, biotechnology and many other socially significant areas of human activity.
Evolution occurs over a period of time exceeding the lifetime of one generation, and consists in changing the inherited traits of the body. The first step in this process is to change the frequencies of gene alleles in a population. In an ideal population in which there are no mutations, natural selection, isolation (crossing selectivity), drift and gene flow, the frequency of alleles, according to the Hardy-Weinberg law, will be unchanged from generation to generation. Thus, evolution in this population will not occur. However, in real populations, there are factors that lead to changes in the frequencies of gene alleles. These are mutations, gene flow, natural selection and gene drift. These factors are factors of evolution. Mutations increase the variability in a population due to the emergence of new allelic variants of genes - mutational variability. In addition to mutational, there is also combinatorial variability due to recombination. Usually, it leads not to changes in allele frequencies, but to their new combinations. However, gene conversion can lead to both the appearance of new alleles and changes in allele frequencies. Another factor leading to a change in allele frequencies is gene flow.