New species evolve via two mechanisms, cladogenesis and anagenesis. Cladogenesis represents the subdivision of a species into two, reproductively isolated, independently evolving forms; whereas anagenesis represent within species evolution. In a study published in PNAS we identify the extent to which cladogenesis influences evolutionary dynamics. Using the fossil record of planktic Foraminifera, combined with modern molecular evidence, we find that cladogenesis is the predominant mechanism by which new species are established at macroevolutionary time scales (over millions of years). Our result has implications for understanding population genetics, community ecology and biodiversity. Our result also differs markedly from the conclusions of previous studies based solely of fossil data, and demonstrates the power of combining fossil data with genetic evidence.