Editing Population size (section)

=== Population bottlenecks and founder effect ===
[[Population bottleneck]]s occur when population size reduces for a short period of time, decreasing the genetic diversity in the population.

The [[founder effect]] occurs when few individuals from a larger population establish a new population and also decreases the genetic diversity, and was originally outlined by [[Ernst Mayr]].<ref>{{cite journal | vauthors = Provine WB | title = Ernst Mayr: Genetics and speciation | journal = Genetics | volume = 167 | issue = 3 | pages = 1041–6 | date = July 2004 | doi = 10.1093/genetics/167.3.1041 | pmid = 15280221 | pmc = 1470966 }}</ref> The founder effect is a unique case of genetic drift, as the smaller founding population has decreased genetic diversity that will move alleles within the population more rapidly towards [[Fixation (population genetics)|fixation]].