Cotton was domesticated from wild ancestors
Like all modern crops, the cotton plants that grow on farms today are descended from species that lived in the wild—and still live in the wild today. These wild cousins are not all that different from domesticated cotton. They grow in warm, dry areas of the world, and they make a big poufy seed pods, filled with seeds that are covered with long, silky fibers.
Thousands of years ago, ancient people discovered that the fibers from wild cotton plants could be spun into ropes or yarn and woven into fabric, and they began farming cotton. As early farmers did with many types of crops, they took advantage of natural variations in the cotton plants. They noticed that some plants were more useful than others—maybe their fibers were longer or stronger, which made for a better yarn. Or maybe some produced bigger seed pods with more fibers. The farmers knew that traits passed through seeds from parent to offspring, so they collected seeds from the best plants and used them for the next year's crop. This process, known as selective breeding, gradually changed wild cotton into a domesticated form that was even more useful.