What Is Natural Selection, What Does It Mean?June 26, 2021
Natural selection, (natural selection or natural selection or natural selection) individual organisms with more favorable features for adapting to the external environment have a higher chance of survival and reproduction than other individuals who do not have these favorable features, and as a result, in terms of transferring their genes to new generations. It is a mechanism that works with its advantages. Thus, individuals and genes that have problems in adapting to the external environment are eliminated from the organism population.
Natural selection works completely on the individual, but only inherited traits can be passed on to the next generation. As a result, since individuals who are more successful in adapting to their environment are more advantageous in terms of survival, reaching puberty and reproductive opportunities, favorable traits are transferred to the next generation and become more common.
By operating in this way, the natural selection mechanism prevents the hereditary characteristics of individuals who are not successful in adapting to be removed from the population and transferred to the next generations. On the other hand, it ensures that the hereditary characteristics of individuals who are more successful in adaptation are transferred to the next generations more effectively. As a result, the population will consist of individuals who are successful in adapting. Given the necessary time, this passive process of adaptations and speciation can result in Adaptive Expansion.
OUTLINES OF NATURAL SELECTION THEORY
This theory has revealed two facts and three hypotheses.
1) All living things tend to reproduce above mathematical rates that will maintain their numbers in the environment. With individuals eliminated, this excess is reduced and populations are kept in balance. This balance is maintained as long as natural conditions remain constant.
2) The hereditary characteristics of individuals in a population of a species are different from each other. In other words, all living populations show variation. Darwin and Wallace could not fully understand the reason for this, and they assumed that variations were an internal feature of living things. Today it is known that these variations occur with mutations.
1) Since the number of surviving individuals is much less than what occurred at the beginning, there must be mutual food, place, etc. for the struggle, as well as heat, cold, humidity, etc. There is a struggle against natural conditions such as This struggle and struggle is a fight for life and death. There is a struggle for survival both between living species with the same food and place requirements, and between individuals belonging to the same species in populations represented by more individuals than normal, that is, in saturated populations. This view was first put forward by Malthus. “FIGHT TO LIVE ”
2) Individuals who have the characteristics (=variations) that will make them adapt well will survive, as they will show a more effective fighting power against individuals who do not have these characteristics in the fight for life, and those who cannot show them perish. Thus, the traits that give the individual the ability to best adapt to those conditions are inherited to future offspring. The key phrase of this assumption is “THE BIOLOGICALLY ADAPTABLE SURVIVES”
3) Since the conditions in one region are different from the others, the selection of the features is also different in each region according to the conditions. The new changes that will occur in the environment allow new adaptations to occur again. This type of adaptation, or more precisely, natural selection, that will occur across many offspring, leads to the emergence of a new group of individuals completely different from their ancestors after a while. reached, these two populations are now treated as two different species. While some individuals in an ancestral population adapt to any new environment with their variation abilities, others can adapt to a different environment due to the different variations they carry. Thus, adaptive opening emerges. However, plants and animals can also bring about many other variations in their struggle for life, which, in their conditions, are neither beneficial nor harmful, and can pass them on to their offspring. (Neutral Mutations)
Darwin’s theory was supported by such plausible and strong evidence that many biologists accepted it immediately. Earlier assumptions could not explain why useless organs and structures arose. It is known that many differences between species today are not important at all in the struggle for survival. But any change in the genes that make up these small differences can cause physiological and structural changes that are of great value in the fight for survival. Genes that produce many traits that do not have adaptive activity may be linked in chromosomes during the days that produce traits that are of vital importance. In this case, these variations can be passed on to future generations without being eliminated. This adaptive active