What four factors can cause the frequency of alleles and genotypes in a population's gene pool to change ; i.g , what four factors can cause evolution to occur?
a- natural selection , mutation, gene flow , and genetic drift
b- weather, season , amount of daylight, and humidity
c- temperature , ph, salinity, and density
d- dominant/recessive , incomplete dominant, co-dominant , and polygenetic traits
The answer is natural selection, mutation, gene flow and genetic drift. Natural selection causes those best adapted genotypes to be favored in a particular environment. This in turn will affect the frequency certain alleles are present in the gene pool. An example of this is called Industrial Melanism which affected the peppered moths in England. When the environment was unpolluted, white moths were common and black moths were rare. Natural selection due to predatory birds occurred--the white moths easily blended in against the light tree bark, while the black moths stood out and were eaten. When the environment became polluted due to the Industrial Revolution, the black moths blended into the soot covered trees while the white stood out and were easily eaten by birds. Gene frequencies changed based on environmental pressures. The different colors of moths are due to different alleles. Mutations can account for new genes in the gene pool. Although most times they can be harmful, in certain environments, they can be helpful and their frequency can increase in the gene pool. Genetic drift refers to a neutral process, not obeying the laws of selection that affects the gene pool. If one individual is "lucky" and leaves behind more copies of their genes because of reproductive success, not necessarily the best adapted genes, genetic drift occurs. More copies of a particular allele can affect evolution as it is passed along to more individuals in a gene pool.