<Li> In regions where geographic isolation is doubtful, species do not exhibit sister pairs . </Li> <Li> Correlation of genetic differences between an array of distantly related species that correspond to known current or historical geographic barriers . </Li> <Li> Measures of reproductive isolation increases with the greater geographic distance of separation between two species pairs . (This has been often referred to as reproductive isolation by distance .) </Li> <P> Allopatric speciation has resulted in many of the biogeographic and biodiversity patterns found on Earth: on islands, continents, and even among mountains . </P>

What is it called when two divergent populations come back into contact after they have speciated