How do random mating, genetic drift, and natural selection influence allele frequency?
Random mating prevents allele frequencies to change, while genetic drift and natural selection do the opposite.
Genetic drift is a chance phenomenon: it takes place when a small sub-population is established from a larger population. It alters allele frequency randomly in very short time. Generally genetic drift is associated with loss of genetic variations .
Natural selection is a slow and directional process. Due to natural forces of selection organisms with particular characters are chosen in each generation while others perish at faster rate. Thus there is a slow but steady increse in frequency of those alleles which are responsible for development of favourable characters, but these changes in allele frequency may take thousands of years to happen.
Random mating prevents change in allele frequency (as described in Hardy Weinberg law) in a population when other evolutionary forces are not acting; though that does not happen in nature.