In population genetics and population ecology, population size (usually denoted N) is the number of individual organisms in a population.
The effective population size (Ne) is defined as "the number of breeding individuals in an idealized population that would show the same amount of dispersion of allele frequencies under random genetic drift or the same amount of inbreeding as the population under consideration." Ne is usually less than N (the absolute population size) and this has important applications in conservation genetics.
Small population size results in increased genetic drift. Population bottlenecks are when population size reduces for a short period of time.
Overpopulation may indicate any case in which the population of any species of animal may exceed the carrying capacity of its ecological niche.
Famous quotes containing the words population and/or size:
“The most advanced nations are always those who navigate the most. The power which the sea requires in the sailor makes a man of him very fast, and the change of shores and population clears his head of much nonsense of his wigwam.”
—Ralph Waldo Emerson (1803–1882)
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—Alex Atkinson, British humor writer. repr. In Present Laughter, ed. Alan Coren (1982)