Education, The science
What is natural selection: for whom is he a friend, and for whom is the enemy?
What is natural selection? Today this question is asked for the first time in high school, during the biology course. In the scientific world, this concept was first popularized by the Englishman Charles Darwin.
The question of what natural selection is, arose in the middle of the nineteenth century in connection with the Darwinian theory of evolution. The development of science for several centuries has pushed the church from its once strong positions.
Great travelers in practice demonstrated that our planet is round, physicians have proved that a person should be treated by scientific methods, not by prayers of monks, and that diseases are caused entirely by terrestrial microorganisms, and not by divine punishment. And then the notion of "natural selection" came to the scientific world. The definition of the term in its brief form says that this is a process through which the number of individuals that are maximally adapted to the surrounding conditions grows in the population. That is, this phenomenon fully revealed the evolutionary theory, according to which unsuitable organisms were forced to change and mutate in order to exist in the world. Actually, this explains the origin of terrestrial species of animals and humans: from primitive to highly developed creatures.
In the course of studying this phenomenon, the researchers identified a number of differently directed processes, which, however, lead to equally successful results. Based on the nature of the influence of the forms of selection on changes in certain characteristics of the population, three forms of selection were identified:
- Driving - in this case, the mutation is activated with a change in the environment directed specifically at the population.
- Stabilizing - this selection is aimed at the destruction of individuals that have too large deviations from the average rate in the population.
- Disruptive is a form that occurs when external conditions are favorable for the emergence of two or more variants of mutations. That is, two species can develop from one population.
More clearly, these options are presented in the following table.
Forms of natural selection: a table of variations
Symptom | Moving | Stabilizing | Disruptive |
Terms of Use | In the case of inconsistent progressive changes in living conditions. | In the case of constant living conditions. | In the period of sudden changes in the external environment in which the body lives. |
Directivity of action | In favor of individuals who have a certain deviation from the mean norms of the trait. | It leads to the destruction of individuals with extreme values of the trait. | Acts against individuals with mean values of the trait. |
Changes | Mutants with one average indicator score are displaced by mutants with a different average. | The mutant group, which has broad reaction rates, is replaced by mutants with narrower norms. | In the process, a group of mutants is eliminated, which has mean characteristic values. |
Result of changes | A new norm of the attribute appears, which more closely corresponds to external conditions. | The average norm of the characteristic is maintained and maintained. | At the site of one, two new average norms are now being formed. |
Examples | Insects and rodents, which are able to develop resistance to poisons. | Insect-polluted plants retain their shape and size to match the insect's needs. | Frequent oceanic winds lead to the fact that only coastal insects survive, or with well-developed or rudimentary wings. |
What is natural selection: the social dimension
With the popularization of sociology, the theory of evolution began to apply also to the social organism. Here, this law looked the same as in the natural world, but acted among people: the strongest survive (succeeds). One who can adapt to society. The concept was called "social Darwinism."
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