Human history, or world history, is the record of humankind from prehistory to the present. Modern humans evolved in Africa around 300,000 years ago and initially lived as hunter-gatherers. They migrated out of Africa during the Last Ice Age, spreading to every continent except Antarctica by its end, 12,000 years ago. Soon afterwards, the Neolithic Revolution in West Asia included the first systematic husbandry of plants and animals, and saw many humans transition from nomadic lives to sedentary existences as farmers in permanent settlements. The growing complexity of human societies necessitated systems of accounting and writing.