What is natural selection?Today this question was first asked in high school, during the course of biology.In the scientific world this concept first popularized by an Englishman, Charles Darwin.
question of what natural selection began in the mid-nineteenth century in connection with the Darwinian theory of evolution.The development of science has been pushed back several centuries the church with its once-strong position.
great traveler in practice demonstrated that our planet is round, doctors proved that a person should be treated scientifically, and not the prayers of the monks, and that diseases are caused by microorganisms entirely earthly, not the divine punishment.And in the scientific world it is the concept of "natural selection."The definition in his brief form says that it is the process by which a growing number of the population in the most adapted to the environment of individuals.That is, this phenomenon is fully revealed the evolutionary theory that unadapted organisms were forced to change and mutate in order to exist in the world.Actually explains the origin of terrestrial species of animals and humans from primitive to highly developed creatures.
What is natural selection: natural evolution of the form and its
During the study of this phenomenon, researchers have identified a number of different processes, which, however, lead to the same successful results.On the basis of the nature of the impact of changes in forms of selection for certain characteristics of the population has been allocated three types of selection:
- Moving - in this case, is activated by mutation directed specifically at population change in the environment.
- stabilizing - this selection is aimed at the destruction of individuals that have too much deviation from the average in the population.
- disruptive - a form that occurs when external conditions are favorable for the occurrence of two or more embodiments of mutations.That is, from the same population can develop two types.
more clearly these options are presented in the following table.
form of natural selection: the table of variations
| Symptom | The driving | stabilizing | disruptive |
| Conditions for | If blurred translational changes in living conditions. | In the case of constant living conditions. | During sudden changes in the external environment in which the organism lives. |
| directed action | in favor of individuals who have a certain deviation from the average trait. | leads to the destruction of individuals with extreme values feature. | action against individuals who have averages feature. |
| Changes | mutants with a single average trait superseded mutants with another average. | group of mutants who have a wide reaction norm, mutants replaced with narrower standards. | During a group of mutants is eliminated, which is the average value of signs. |
| result of changes | There is a new sign of the norm, which is more consistent with the external conditions. | average rate characteristic is stored and maintained. | In place of a now form two new average rates. |
| Examples | insects and rodents, which are able to develop resistance to poisons. | Entomophilous plants retain their shapes and sizes to fit the needs of the insect. | Frequent ocean winds lead to the fact that the only surviving coastal or insects with well-developed, or with rudimentary wings. |
What is natural selection: the social dimension
With the popularization of sociology theory of evolution began to apply also to the public body.Here, the law looked the same as in the natural world, but among people acting: to survive (succeeds) the strongest.Anyone who can adapt to society.The concept is called "social Darwinism."
