Changes in allele frequency

Environmental selection pressures

external agents which influence the ability of an individual to survive in their environment

Natural selection

occrs when a selective pressure act on a population in the wild and produces differences in the survivial and reproduction rates of variant in the population

Fitness

the ability to survive and pass genetic material to the next generation

Selective advantage 

relatively higher genetic fitness of a phenotype compared to others

genetic drift

random changes in allele frequency from one generation to the next due to chance events

Bottleneck effect

chance effects on allele frequencies in a population as a result of a major reduction in population size

Founder effect

chance effect on allele frequency in a population that is formed from a small unrepresentative sample of a larger population

gene flow

movement of individuals and their genetic material between populations

Immigration

movement of individuals and their alleles into a population

Emigration

movement of individuals and their alleles out of a population