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Over time, the isolation by distance model reveals a decline in local isolation and a rise in short and long range migration and the Sandy population experienced an isolate breakdown over time. Distance plays a role in determining kinship, but becomes less significant over time as the measures of the fit of the model decline.
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time.Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. [1]
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. All modern species diversity is a product of genetic isolates ...
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.
A variation of peripatric speciation in which speciation occurs by geographic isolation, but reproductive isolation evolves in the larger population instead of the peripherally isolated population. [12] In centrifugal speciation, the range of an original population (green) expands and then contracts, leaving an isolated fragment population behind.
Hybrid zones can form from secondary contact. A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. . Hybrid zones can form in situ due to the evolution of a new lineage [1] [page needed] but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their ...
In evolutionary biology, sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography , sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places.
The lack of geographic isolation as a definitive barrier between sympatric species has yielded controversy among ecologists, biologists, botanists, and zoologists regarding the validity of the term. As such, researchers have long debated the conditions under which sympatry truly applies, especially with respect to parasitism .