Natural selection for Darwin
Natural selection is the main driving forceevolution of all living organisms. The existence of this factor was found out by several British researchers: Blythe, Matthew, Wallace, Wells, Darwin. However, only the latter, having revealed the significance of this phenomenon, created the theory of natural selection. According to Darwin, the most adapted organisms survive, as a result of which, on the basis of uncertain genetic variability in generations, there is an evolutionary process.
Natural selection is conservationfavorable individual changes and differences on the background of the destruction of harmful. Thus, according to Darwin, the main driving force of evolution contributes to the improvement of every organic being in the conditions of its existence.
As a provoking factor, natural selection is endowed with certain characteristics. The main ones are: adaptive orientation, accumulating and integrating impact, probabilistic nature.
The probability character is determined by the two sides of the selection process: stochasticity and statistical nature.
The quantitative concept (statistical)It is used to characterize a structure that has many components in its composition, independent of each other. In conditions of living nature, such a system is a population. It consists of individuals unequal in fitness.
The term "stochastic" is used in describing phenomena using probability theory.
Natural selection presupposes both survival,and reproduction of individuals. In other words, the individual, more adapted to survival and reproduction, has great potential to leave offspring. At the same time, the probabilistic nature manifests itself in the tendency to separate the more adapted representatives of the group, but not necessarily an individual that is better adapted than others.
Natural selection is characterized by accumulationaction. It consists in the gradual accumulation of small useful genetic changes. This leads to the improvement of the signs of adaptation or the appearance of new ones.
Scientists have long been trying to establish a classificationthe driving factor of evolution. However, the system is still being developed. This is mainly due to the fact that natural selection and its forms are difficult to unite in a clear structure. This, in turn, is due to the inability to determine a single core of classification.
The most logical solution to this problem, according to scientists, is the delineation of the characteristics of influence and the very nature of selection.
Thus, there are two main types of causal factor of evolution: stabilizing and driving.
Motion selection acts as a forcecreative. Its mechanism is based on preserving useful deviations from the average indicator of the accepted norm, which are adapted to the new environmental conditions, thanks to the emission of representatives of the past norm.
The motive selection is interrelated with the stabilizing one. At the same time, both these concepts are two facets of one process.
The stabilizing factor presupposes the preservation of the norm established in specific conditions when eliminating deviations.
Of course, natural selection is the mostessential, however, not the only evolutionary factor. Changes in the gene pool of populations are also brought about by mutations. However, they occur extremely rarely, and therefore do not make a significant contribution to evolution.
It is necessary to distinguish between the natural andreproductive selection. These two phenomena may not coincide with each other. The tasks of the first are to "reject" the unfavorable variants of variability, and also to influence the nature of the process of evolution itself.
