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Back The Hardy- Weinberg Eqiullibrium states that the genotype frequencies and gene frequencies of a large, randomly mating population remain constant provided immigration, mutation, gene flow, genetic drift and selection do not take place. Becuase it is naturally impossible to meet all of these standards, no natural population will remain constant. __Mutations__- A mutation is a change of the DNA sequence within a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the parental type. Evloution, which is a cause of inconsistency in a population, can only occur with new alleles. The only way that new alleles are created is by mutations, which natural selection can then work on. __Gene Flow__- Transfer of genes from one population to another of the same species, as by migration or the dispersal of seeds and pollen. Many species are composed of populations whose members breed within the group. Each population can develop a gene pool that is different from other populations of the same species. But, sometimes members of one population will breed with members of another population, which will bring new genes into the population and alter the existing frequencies. In addition to migrating within the species to breed, sometimes breeding occurs between two different species. This is called hybridization. In either case, gene flow increases the variability of the gene pool, making the population inconsistent. __Genetic Drift__- When a popuaion is small, numbers of certain members may be thrown out of proportion because they are eliminated purely by chance. When this happens, the population may experience directional selection. This is where conditions favor one of the exptreme phenotypes. __Nonrandom Mating__- Random mating is a population mating system in which every female gamete has an equal opportunity to be fertilized by every male gamete. When individuals in a population have preferences about thier mates, allele frequencies could be altered. Certain individuals are not able to make their contributions to the next generation, thus making the population inconsistent.http://www.thefreedictionary.com __Natural Selection__- Natural selection is the process where only the organisms best adapted to their environment survive and transmit their genetic characteristics in increasing numbers to proceeding generations while those less adapted are to be eliminated. Either outcomes of natural selection lead to inconsistencies in the population.

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