Key Concept 1.1 Throughout the Paleolithic period, humans migrated from Africa to Eurasia, Australia, and the Americas. Early humans were mobile and creative in adapting to different geographical settings from savanna to desert to tundra. Humans also developed varied and sophisticated technologies.
Key Concept 1.2 In response to warming climates at the end of the last Ice Age, about 10,000 years ago, some groups adapted to the environment in new ways, while others remained hunter-foragers. Settled agriculture appeared in several different parts of the world. The switch to agriculture created a more reliable, but not necessarily more diversified, food supply. Farmers also affected the environment through cultivation of selected plants to the exclusion of others, the construction of irrigation systems, and the use of domesticated animals for food and labor. Populations increased; village life developed, followed by urban life with all its complexity. Patriarchy and forced-labor systems developed, giving elite men concentrated power. Pastoralism emerged in parts of Africa and Eurasia. Like agriculturalists, pastoralists tended to be more socially stratified than hunter-foragers. Pastoralists’ mobility facilitated technology transfers through their interaction with settled populations.
Key Concept 1.3 About 5,000 years ago, urban societies developed, laying the foundations for the first civilizations. The term civilization is normally used to designate large societies with cities and powerful states. While there were many differences between civilizations, they also shared important features. They all produced agricultural surpluses that permitted significant specialization of labor. All civilizations contained cities and generated complex institutions, including political bureaucracies, armies, and religious hierarchies. They also featured clearly stratified social hierarchies and organized long-distance trading relationships. Economic exchanges intensified within and between civilizations, as well as with nomadic pastoralists.
As populations grew, competition for surplus resources, especially food, led to greater social stratification, specialization of labor, increased trade, more complex systems of government and religion, and the development of record keeping. As civilizations expanded, people had to balance their need for more resources with environmental constraints. Finally, the accumulation of wealth in settled communities spurred warfare between communities and/ or with pastoralists; this violence drove the development of new technologies of war and urban defense.