Population size

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Population size" – news · newspapers · books · scholar · JSTOR (December 2017) (Learn how and when to remove this message)

In population genetics and population ecology, population size (usually denoted N) is a countable quantity representing the number of individual organisms in a population. Population size is directly associated with amount of genetic drift, and is the underlying cause of effects like population bottlenecks and the founder effect.^[1] Genetic drift is the major source of decrease of genetic diversity within populations which drives fixation and can potentially lead to speciation events.^[1]