Humans first began collecting and growing edible grains, fruits and roots, and corralling wild animals for meat, milk, and material goods thousands of years ago. Ever since, we have been shaping these plants and animals to meet our needs and desires. Compare corn to its ancestor, teosinte, cattle to the aurochs from which they were derived — or any other crops and livestock on which we rely to their wild relatives — and you’ll find the remarkable story of human agriculture and the transformative power of artificial selection.
The success our ancestors had in creating the modern cornucopia of domesticated plants and animals is all the more remarkable for their near-complete lack of understanding of where new traits come from or how they pass from one generation to the next. They didn’t know that every trait they favored arose through one or more random alterations — mutations — to a species’ genetic code, passed on from parents to their offspring in the form of DNA.