Related topics: population

China's new family planning policy comes from old playbook

China's universal three-child policy was passed into law this past August to boost the country's birth rate, after a two-child limit—implemented more than five years ago—failed to do so.

New frog species 'hopping' into protection

A new frog species has been discovered in Wollumbin National Park in northern New South Wales, and is one of only two known species that store their tadpoles on their bodies.

Geneticists map the rhinoceros family tree

There's been an age-old question going back to Darwin's time about the relationships among the world's five living rhinoceros species. One reason answers have been hard to come by is that most rhinos went extinct before the ...

Return of the sprat: 'Vital' small fish thrive in the Clyde Sea

Small fish that live in open water and form a significant part of the base of the marine food chain have returned in huge numbers to the Clyde Sea, according to new research from scientists at the University of Aberdeen.

Fecal records show Maya population affected by climate change

A McGill-led study has shown that the size of the Maya population in the lowland city of Itzan (in present-day Guatemala) varied over time in response to climate change. The findings, published recently in Quaternary Science ...

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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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