Everywhere we look in the natural world, there's evidence of natural selection: the resin armor of a lodgepole pine cone evolved to defend against seed-hungry birds and squirrels; the long neck of a giraffe was evolutionarily favored for reaching high vegetation that the competition can't touch. We know that natural selection shapes how animals and plants evolve and adapt. But does natural selection also influence an organism's very capacity to evolve? And if so, to what degree?