We have now reached the fourth part of my series on Wikipedia and the evidence for common descent. In previous entries, I discussed Wikipedia’s arguments for common descent based on comparative physiology / biochemistry, comparative anatomy, and paleontology. Now I am going to address the arguments from biogeographical distribution. Biogeography is essentially the study of the geographical and historical distribution of species in relation to one another. The argument holds that species are related in accordance with their geographical proximity to one another.