Steamy and wet they may be, but tropical hotspots of biodiversity are not the hottest as far as evolution is concerned. It turns out that new species emerge more frequently in temperate regions than in the tropics.
Tropical zones do host a greater species diversity, but that’s because fewer species have gone extinct there, say Jason Weir and Dolph Schluter at the University of British Columbia in Vancouver. They looked at pairs of “sister” species – pairs that evolved from an immediate common ancestor – and estimated how long ago the sisters diverged from each other.
Near the equator, sister species split…
