In the process of natural selection in a population remain and grow those individuals who are best suited to the survival of the most adaptable.The term made popular at the time, Charles Darwin.He introduced it to be compared with the artificial selection and show that, in principle, in both cases, the same process occurs.The only difference is in who appreciates needed or not certain properties - habitat or people.
form of natural selection are classified on the basis of many criteria.Widespread typology proposed II Schmalhausen.Determining the types of natural selection, it was based on how they affect the volatility or stability of a particular trait in a population.The question of their number still remains unclear.But major in biological science is still considered the following three forms of natural selection: tearing (disruptive), the guide (motion) and stabilize.The genotypes have a more diverse species, the more successful the process.
result of dynamic selection becomes binding abnormal signs.It was first described by Wallace and Darwin.If this selection advantage is given to those individuals who have symptoms, strongly deviate in one direction or another.
he manifested when expanding or changing habitat environment.Then the creatures are forced to change in a certain direction, to adapt to new conditions.For example, if the terrestrial mammals are forced to go to live under the ground, their limbs gradually adapt to the new conditions and become burrowing.
stabilizing form of natural selection is focused on the preservation of individuals who have expressed a definite sign of an average degree, and also to reject those that it is too far from the norm.For example, more likely to survive in birds, with a standard size of the wing, not too big or small.
Action disruptive selection the previous two opposite influence.It occurs when the conditions are ideal for the further development of a sign in its extreme form, but not in the middle.As a result of the initial form may not appear alone, and even a few new ones.Thus, disruptive selection could be the cause of all-new, not previously existing species.
In nature, often a situation when the same population lives in different places.Accordingly, its members are adapted to their differing ecological niches.
example of artificially conducted disruptive selection is known throughout the experiment with fruit flies.After hybridization to select a steel specimens having either the maximum or minimum number of bristles, the two groups of steel ranging from the thirtieth generation of very different, although they continued to hybridize with.
Apart from the three main forms seen in biology, sexual selection.His influence is important.After all, every individual is necessary not just to adapt and survive, but also like a partner to continue his race.
There are two hypotheses to explain the mechanism of action of sexual selection.
According to the first female chooses the male already, because he has managed to survive to maturity, despite the bright appearance.This means that he has good genes and pass them on to the next generation.
second hypothesis explains the choice of pairs of differently.According to her, a bright female partner was chosen for attractive color, considering that the next generation must be the same, and to choose for breeding.
addition to the three mentioned above, there are individual and group form of natural selection.The first aims to save some individuals having features that enable them to survive and exist within its population.A group establishes quality, useful for all kind.
all existing forms of natural selection are not randomly, by chance once, but gradually, as the generations population retains certain characteristics.
