Editing Population size (section)

{{Short description|Total number of individuals in a defined group or area}}
{{More citations needed|date=December 2017}}
In [[population genetics]] and [[population ecology]], '''population size''' (usually denoted ''N'') is a [[countable quantity]] representing the number of individual [[organism]]s in a [[population]]. Population size is directly associated with amount of [[genetic drift]], and is the underlying cause of effects like [[population bottleneck]]s and the [[founder effect]].<ref name="Wright_1929">{{Cite journal|last=Wright|first=Sewall | name-list-style = vanc |date=November 1929 |title=The Evolution of Dominance |journal=The American Naturalist|language=en|volume=63|issue=689|pages=556–561|doi=10.1086/280290 |bibcode=1929ANat...63..556W |s2cid=85301374 }}</ref> Genetic drift is the major source of decrease of genetic diversity within populations which drives fixation and can potentially lead to [[speciation]] events.<ref name="Wright_1929" />