People love to trip out on the future of homo sapiens, usually conjuring some kind of twinkly transcendence (a seraphic super-race) or dystopian degeneracy (machine-dependent dullards enfeebled by our own technology). But those stories owe more to wishful thinking or baseless anxiety than to actual evolutionary theory. I decided to forgo the fantasizing and explore the science itself: the forces that shaped our species and that are still at work, however subtly, today. Evolutionary biologist Barry Sinervo joined me to explain the scientific fundamentals and offer some educated guesses on what comes next.