Related topics: population

Predicting changes in microbial food webs

Increasing either temperature or nutrients can hurt ecosystems by destabilizing food webs, which are all of the interconnected food chains that make communities behave the way they do. When temperature and nutrients increase ...

Demographic modeling plays back tape of wheat evolution

Wheat, which includes bread wheat and its relatives, is a staple food crop that feeds about 35% of the world's population. As one of the first ancient crops to appear in the Fertile Crescent, wheat has been cultivated for ...

Genetics as a conservation tool for endangered chimpanzees

The western chimpanzees of Guinea are threatened by mining activities. Using a novel genetic approach, UZH researchers and an international team have collected information on population size and community structure of the ...

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Population size

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.

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