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Genographic Project. ISOGG. v. t. e. Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure. [1] Population genetics was a vital ingredient ...
Population density is the number of people per unit of area, usually transcribed as "per square kilometer" or square mile, and which may include or exclude, for example, areas of water or glaciers. Commonly this is calculated for a county, city, country, another territory or the entire world . The world's population is around 8,000,000,000 [3 ...
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]
A demographic structure of a population is how populations are often quantified. The total number of individuals in a population is defined as a population size, and how dense these individuals are is defined as population density. There is also a population's geographic range, which has limits that a species can tolerate (such as temperature).
This is a list of countries and dependencies ranked by population density, sorted by inhabitants per square kilometre or square mile. The list includes sovereign states and self-governing dependent territories based upon the ISO standard ISO 3166-1. The list also includes unrecognized but de facto independent countries.
Population structure (also called genetic structure and population stratification) is the presence of a systematic difference in allele frequencies between subpopulations. In a randomly mating (or panmictic) population, allele frequencies are expected to be roughly similar between groups. However, mating tends to be non-random to some degree ...
Genetic isolate. A genetic isolate is a population of organisms that has little to no genetic mixing with other organisms of the same species due to geographic isolation or other factors that prevent reproduction. Genetic isolates form new species through an evolutionary process known as speciation.
Delayed density dependence has been used by ecologists to explain population cycles. [2] Ecologists have been unable to successfully explain regular population cycles for many decades; delayed density dependence may hold the answer. [2] Here populations are allowed to increase above their normal capacity because there is a time lag until ...