essence of the concept of evolution of Darwin is reduced to a line of logic, confirmed by experiments and other research positions.Thus, it was proved that all types of living organisms peculiar to individual genetic variation on any grounds;they multiply exponentially;within species is a struggle for existence in force restrictions of vital resources;in the struggle to survive and then reproduce only adapted individuals.
Thus, the main driving forces of evolution - a genetic variation, natural selection and the struggle for existence.Let us consider in more detail each of them.
1. Hereditary variability is an improvement of chromosomes and genes as well as the emergence of various combinations of parental traits in the offspring, meaning it is caused by mutations.The variety of inherited traits is due to the repetition of mutation and contact between individuals is also plays a role of their environment.
evolution of living organisms involves changing the genetic background and the creation of th
variability is of three types:
a) certain - the acquisition of a certain number of units of one type of new features;
b) indefinite variability - the emergence of a variety of minor features that can not be explained, the representatives of one species;
c) correlative - the interdependence of acquired characteristics of an organism.
Thus, the driving force of evolution, namely genetic variation arising from the interplay of genetic information and the specific conditions of the environment.At the same time acquired the symptoms persist for many generations.
2. The struggle for existence - the mechanism of the relationship between organisms and non-living factors of nature, due to the ability of individuals to reproduce (ascending order of their numbers) and limited resources (territory, food, etc.).There are following its forms:
a) struggle with critical environmental conditions, such as excess or deficiency of light, moisture, air temperature change;
b) struggle within certain kind - is the result of similarity needs of members of this type;
c) interspecific struggle - is expressed in the relationship between members of different species.
Thus, such driving forces of evolution, the variability and the battle for existence, are closely interrelated, since the first device type contributes to the conditions of inanimate nature, which leads to biological progress.
3. natural selection - survival mechanism identifies units with the necessary genetic changes and their further reproduction.The selection is the result of the struggle for existence.Allocate following its mechanisms:
a) the formation of genetic changes;
b) survival and individuals to these changes in an appropriate environment;
c) the reproduction of these items, the increase in their numbers and distribution of useful genetic changes.
driving forces of evolution, interacting with each other, help to explain the formation of other species in nature.The materials accumulated in the various branches of biology, have a logical conclusion, only if they comply with the principle of evolution.
great merit of Charles Darwin is to explain the development process and the formation of species.This fact made the evolutionary theory of Darwin's theory accepted.