ALLELE FREQUENCY AND NATURAL SELECTIONAn allele frequency is a proportion of a specific allele among all other alleles. It is the amount of trait expressed in a population. The four different ways that allele frequency can change is mutation, migration, genetic drift, and natural selection. A mutation is the only way new alleles are created due to a change in the DNA codon. Because of this change, the amino acid sequence is changed, which changes the protein. A mutation can be harmful or helpful. For example, a frog with an extra leg can be a harmful mutation since it needs to eat more in order to "feed" the extra leg. Mutations may not or may affect reproductive success. Migration is when a group of individuals move from one pace to another because of a geographic border or element. For example, three species are located on one side of a mountain and another species is located on the other side. After a winter storm, one of the three different species is migrated to the other side of the mountain, that species because the migrant. Genetic drift refers to a random change in allele frequency. For example, the Founder Effect refers to one particular species moving into a different area and creating a larger population of that species. Another example would be the Population Bottleneck where adaptions don't matter but earthquakes or human activities reduce the size of a population. Natural selection refers to "survival of the fittest". Those best suited to the environment will survive and reproduce. Biological traits become either more or less common in a population due to the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. The types of natural selections are Stabilizing, Directional, and Disrupted. Stabilizing selections is when the environment supports the medium trait, therefore it sucks to be at the start and at the end. Directional selection is when the environment supports either extreme. Disrupted Selection is when the environment supports one extreme, therefore it stinks to be medium.
|
EMPEROR NEWT'S ADAPTIONS
My Prezi on organism of the world ! |