<Li> In occurrences where several pairs of related species share a range, they are distributed in abutting patterns, with borders exhibiting zones of hybridization . </Li> <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>

The change in one population driven by a change in an associated population is called