Domestication began inadvertently as humans interacted with wild animals and plants. Over generations, humans selected species that were less fearful and produced more desirable traits, resulting in domesticated versions. Dogs were likely domesticated twice - once in Asia from wolves and once in Europe/Middle East. Belyaev's fox experiment showed how rapidly selection for tameness can change physical and behavioral traits. Many common livestock like cattle, sheep, goats, pigs, horses, and several grain and vegetable species have been domesticated from their wild progenitors over thousands of years through this process. Domestication transformed human societies from nomadic hunter-gatherers to sedentary agriculturalists.