as the world headed into a cooler, drier climate around 250 million years ago, the early seed-bearing plants had a distinct advantage over their simpler, spore-releasing relatives that then flourished in moist, warm swamps.

Seed-bearing plants also figured out better ways to get around. Some seeds sprout improbably elaborate barbs in order to snag a lift on passing animals. A significant number hitch a ride by growing a morsel called a elaiosome that entices ants to carry them off a few feet. Other seeds are textured or buoyant, so they can float away on wind or water.

The human appetite for seeds has resulted in new forms of dispersal as well. Thousands of years ago, people began collecting and cultivating nutrient-rich seeds, like corn, lentils, and oats, for food.