1) Why is the Hardy-Weinberg law useful?
2) Define genetic drift?
2) What factors influence the mutation rate of a population?
3) Briefly explain the difference between stabilizing selection, directional selection, and disruptive selection?
Hardy-Weinberg's law describes a theoretical situation in which a population is undergoing no evolutionary change. It explains that if the evolutionary forces are absent, the population is large, its individuals have random mating, each parent produces roughly equal number of gametes and the gametes produced by the mates combine at random and the gene frequency remains constant.
The random changes in gene frequencies occurring by chance and not under the control of natural selection are called genetic drift.
Radiations, chemical mutagens and enviornment influence the mutation rate of a population.
The stabilizing selection is the natural selection that acts in the absence of large scale environmental change for long period.
Directional selection produces a regular change within a population in one direction in respect to certain characteristics.
The disruptive selection acts to break up a previously homogeneous population into several different adaptive norms.