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Mutations

 

They are the result of the changes in the molecular structure of the DNA, at a certain speed of mutation, the mutagenics can influence in the greater or smaller speed.

DERIVES GENIC

In great populations the chance can give like result some variation of the frequencies of the genes which can be predicted by means of the law of the balance of Hardy Weimberg, these variations normally are so small that they can be as insignificant.

Most of the populations they are not very great because if we considered the number of individuals that can generate we see that it is a very small number. It can happen that a certain one I stupefy once appears single (recesivo) and the chance produces that it disappears vice versa in the following generation or, to this is known him as it derives genic.

Stebbens indicates that any species that we consider tends to maintain a number of individuals determined, but between alive beings of life cuts the populations fluctuan of year in year.

LEVELS OF EVOLUTIONARY CHANGE

There are two basic models for the evolution, the evolution that follows a sequence regular, is of one or alleles in a population divergent evolution and the modification generation in generation when from a single ancestral population are two lines of divergent population.

Savage proposed a classification of the levels of evolutionary change:

 

Process Standard All the processes better give alive beings provided to live in the environment in which they are
microevolution Sequential
Species Divergent
Macroevolution Divergent
Superevolution Divergent

Species

Process by means of as new species from a given population are developed. According to the isolation mechanism we spoke of:

Allopatric , when the segments of a population are aislan geograficamente. The two isolated portions can accumulate enough genetic differences throughout the time (microevolution), arrives a little while in which auqnue is joined cannot be crossed between if, many espcies can have appeared by this cause,

Sympatric, in a population of a species a single mutation in a part of the population gives rise to that this part is isolated of the other and each one evolves.

Macroevolution

It is the evolution of groups over the species level. It such uses mechanisms that the microevolution, but the speed and amount are greater, occupied habitats empty. The marine vegetables can undergo processes of Species and microevolution, but also of macroevolution when occupying semiacuaticas or terrestrial zones.

Superevolution

When a population changes of an adaptive zone to another one successfully. All the groups of a population do not contain the adapted genes so that these changes take place, most on attempts are not successful.

GENERAL RULES OF THE EVOLUTION

When a group begins in an adaptive sense becomes the inverse sense impossible.

Law of Dolo, the evolution is an irreversible process

Law of Cope, the tendency to the increase of size is common in the beings better adapted

Law of Gause, two espcies with identicos ecological requirements cannot occupy the same ecological niche indefinitely.

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