Natural Selection

Date: 2015-10-07; view: 458.

Population waves

Population waves are process of individuals quantity changing in a population. When the quantity of individuals is getting more a natural habitat and level of migrations is getting more two. When the quantity of individuals is getting less a natural habitat and level of migrations is getting less two.

Not all members of a population necessarily have an equal chance of surviving and reproducing (due to competition for resources and mates). By virtue of small phenotypic variations, some individuals are better adapted to their environment than are others. The better adapted individuals are more "fit" and tend to survive and reproduce, passing on their adaptations to the next generation in greater frequency than those adaptations of the less "fit" members of the population.

Fitness is a measure of an individuals ability to survive and reproduce. Those with the highest fitness are more likely to survive and reproduce. Thus, they make a greater contribution to the gene pool, of the next generation than do those less "fit".

Natural selection is the process of differential survival and reproduction that inevitably leads to changes in allele frequencies over time as those individuals who are the most "fit" survive and leave more offspring.

There are three patterns, or types, of natural selection: stabilizing selection, directional selection,and disruptive selection.