By 14,000 years ago, the Ice Age was winding down. As the ice melted, oceans rose, and coastlines changed, some environmental barriers between populations vanished. While elsewhere, new ones appeared. Temperatures and rainfall increased dramatically. And some areas became so rich in plants and animals, that people no longer had to travel in search of food. Instead, people settled into more permanent villages based on foraging. By planting the seeds from wild grains near their homes, they could supplement their food supplies, and stay in the same spot year round. Perhaps as they became more sedentary, they had more opportunities for other, ahem, pursuits. In any case, populations grew and pretty soon, growing families in these villages became less suited to the nomadic lifestyle. In some places, during droughts or harsh winters, local wild plants and animals could no longer support everyone. Independently and all over the world, people began making the same discovery, which would change human societies and the natural environment forever. They developed AGRICULTURE! It's not an obvious choice, hunter-gatherers can provide food for their families, by working only a few days a week. Farming, on the other hand, is hard work, and a full-time job. But farming provided more food to feed larger populations consistently Villages began relying more and more on their gardens. As mutant varieties of wild grains occured, these early agriculturists chose the crops with larger seeds and grain ears that were easier to gather. People also domesticated docile, local animals. Villages grew, especially in areas with fertile soil, and became cities. And settled people became more detached from the natural world. By 6,000 years ago, in Mesopotamia, there were cities with wealth, power, and a new social order. Whoever controlled grain supplies wielded power. And some people no longer had to find or produce their own food, but rather exchange their services for dinner. Agricultural societies soon became the dominant way of life for people throughout the world. World populations exploded, creating more laborers to produce more crops, to feed more mouths, more land had to be cleared for farming. Sometimes, whole towns relocated when soils couldn't sustain repeated cultivation. And each year, people took their livestock farther and farther afield to graze. Groups who had been separated for thousands of years came in contact as they traveled in search of land, labor, and trade goods. New means of transportation brought distant cultures in contact. New families produced from these contacts blurred genetic distinctions within continents, and all around the world. Migrating farmers encountered hunter-gatherers. In sub-Saharan Africa, for example, farmers spread east and south from present-day Cameroon around 5,000 years ago. Along the way, they met and absorbed many of the people whose ancestors had been living there for thousands of years. Some hunter-gatherers who lived next to farming communities took up farming themselves. But others followed game to areas unsuited to agriculture. By 1,500 years ago, agriculture dominated most of sub-Saharan Africa. But the Calahari Desert, too harsh for farming, remained a home of hunter-gatherers, who kept not only much of their lifestyle, but also their unique click languages. In most places throughout the world, however, agriculture triumphed. As the new farmers on each continent expanded and absorbed other hunter-gatherer groups. Genetic differences within continents began disappearing, setting the stage for the most recent chapter in our human story.