evo_v70_i7_iss2press_coverA fundamentally interesting aspect of biological diversity is that there is lots of genetic variation within species (and among closely related species that occupy different ranges). In phylogeographic studies, we try to sort out which processes determine how this geographic variation comes about and why certain variants are found in certain places. Phylogeography can illuminate how new species come about, and how species ranges change over time. Some of my recent work involving phylogeography has examined speciation in African sunbirds and range expansion in central/North American coralsnakes.