Key Concept 3.1 Although Afro–Eurasia and the Americas remained separate from one another, this era witnessed a deepening and widening of networks of human interaction within and across regions. The results were unprecedented concentrations of wealth and the intensification of cross-cultural exchanges. Innovations in transportation, state policies, and mercantile practices contributed to the expansion and development of commercial networks, which in turn served as conduits for cultural, technological, and biological diffusion within and between various societies. Pastoral or nomadic groups played a key role in creating and sustaining these networks. Expanding networks fostered greater interregional exchanges while at the same time sustaining regional diversity. Islam, a new monotheistic religion, spread quickly through practices of trade, warfare, and the diffusion that was characteristic of this period.
Key Concept 3.2 State formation in this era demonstrated remarkable continuity, innovation, and diversity in various regions. In Afro–Eurasia, some states attempted, with differing degrees of success, to preserve or revive imperial structures, while smaller, less centralized states continued to develop. The expansion of Islam introduced a new concept—the caliphate—to Afro–Eurasian statecraft. Pastoral peoples in Eurasia built powerful and distinctive empires that integrated people and institutions from both the pastoral and agrarian worlds. In the Americas, powerful states developed in both Mesoamerica and the Andean region.
Key Concept 3.3 Changes in trade networks resulted from and stimulated increasing productive capacity, with important implications for social and gender structures and environmental processes. Productivity rose in both agriculture and industry. Rising productivity supported population growth and urbanization but also strained environmental resources and at times caused dramatic demographic swings.
Shifts in production and the increased volume of trade also stimulated new labor practices, including adaptation of existing patterns of free and coerced labor. Social and gender structures evolved in response to these changes.