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Allopatric speciation (from Ancient Greek ἄλλος (állos) 'other' and πατρίς (patrís) 'fatherland') – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model [1]: 86 – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.
Allopatric speciation, in which two populations of the same species are geographically isolated from one another by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation. Peripatric speciation, in which a small group of a population is separated from the main body and experiences genetic drift.
The isolated populations then undergo genotypic or phenotypic divergence as: (a) they become subjected to dissimilar selective pressures; (b) different mutations arise in the two populations. When the populations come back into contact, they have evolved such that they are reproductively isolated and are no longer capable of exchanging genes.
The disappearance of a central population poses a major threat of population bottleneck. The remaining two populations are now geographically isolated and the populations face an unstable future with limited remaining opportunity for gene flow. [23] Genetic bottlenecks exist in cheetahs. [24] [25]
Biogeography is a synthetic science, related to geography, biology, soil science, geology, climatology, ecology and evolution. Some fundamental concepts in biogeography include: allopatric speciation – the splitting of a species by evolution of geographically isolated populations; evolution – change in genetic composition of a population
The bottom chart measures the genetic distance between all pairs of populations according to the Fst statistic. Populations separated by greater distance are more dissimilar than those that are geographically close. Isolation by distance (IBD) is a term used to refer to the accrual of local genetic variation under geographically limited ...
Whereas in allopatric or peripatric speciation—in which geographically isolated populations may evolve reproductive isolation without gene flow—the reduced gene flow of parapatric speciation will often produce a cline in which a variation in evolutionary pressures causes a change to occur in allele frequencies within the gene pool between ...
In biology, a refugium (plural: refugia) is a location which supports an isolated or relict population of a once more widespread species. This isolation can be due to climatic changes, geography, or human activities such as deforestation and overhunting. Mountain gorilla