Related topics: population

A diaspora-based model of human migration

How do migrants choose their destinations? Existing models, known as "gravity models," use population size and travel distance as explanatory variables—and often fail, especially at the neighborhood scale. Many migrants ...

Why European colonization drove the blue antelope to extinction

The blue antelope (Hippotragus leucophaeus) was an African antelope with a bluish-gray pelt related to the sable and the roan antelope. The last blue antelope was shot around 1800, just 34 years after it was first described ...

Q&A: The impact of China's rapidly aging society

Due to its economic growth and large population, the People's Republic of China is widely viewed as a rising economic and military superpower. But declining fertility rates and increased life expectancies over the last few ...

New data confirms swift parrot population fears

A new evaluation from The Australian National University (ANU) of the number of swift parrots left in the wild has confirmed their population size is likely only a few hundred and declining rapidly.

Becoming human: An ancient genome perspective

Writing a commentary in the 50th anniversary issue of Cell, Fu Qiaomei and E. Andrew Bennett, both of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, explored 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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