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Isolation index measures the degree to which people inhabit geographic units inhabited primarily by members of their own group. It is usually denoted by I. It is usually denoted by I. It varies from 0 to 1.0 and is defined as the proportion of own-group members in the unit of the average person.
The realms delineate large areas of Earth's surface within which organisms have evolved in relative isolation over long periods of time, separated by geographic features, such as oceans, broad deserts, or high mountain ranges, that constitute natural barriers to migration. As such, biogeographic realm designations are used to indicate general ...
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 ...
The fauna of South America consists of a huge variety of unique animals some of which evolved in relative isolation. The isolation of South America allowed for many separate animal lineages to evolve, creating a lot of originality when it comes to South American animal species. [1]
This page features a list of biogeographic provinces that were developed by Miklos Udvardy in 1975, [1] [2] later modified by other authors. [according to whom?] Biogeographic Province is a biotic subdivision of biogeographic realms subdivided into ecoregions, which are classified based on their biomes or habitat types and, on this page, correspond to the floristic kingdoms of botany.
where (comparing a black and white population, for example): a i = the population of group A in the i th area, e.g. census tract A = the total population in group A in the large geographic entity for which the index of dissimilarity is being calculated. b i = the population of group B in the i th area
[1]: 189 A classic example of habitat isolation occurring in allopatry is that of host-specific cospeciation [1]: 189 such as in the pocket gophers and their host chewing lice [24] or in the fig wasp-fig tree relationship and the yucca-yucca moth relationship—examples of ecological speciation caused by pollinator isolation.
For example, differential fusion implies greater postzygotic isolation among sympatric species, as this functions to prevent fusion between the species. However, Coyne and Orr found equal levels of postzygotic isolation among sympatric and allopatric species pairs in closely related Drosophila . [ 8 ]