Prehistory of native Americans on the Central American land bridge: Colonization, dispersal, and divergence

The Central American land bridge has served as a passageway for animals and humans moving between North and South America. Nevertheless, after the first waves of human immigration at the end of the Pleistocene, contact between the native peoples who remained on this isthmus and other peoples living in continental areas where civilization ultimately developed, is characterized, according to the field record, by the transfer of crops, technologies, and goods, until ca. 1400 BP when speakers of Mesoamerican languages occupied the northwestern edge (Gran Nicoya). The ancestors of modern-day speakers of Chibchan and Chocoan languages underwent social and cultural diversification mostly within the confines of the land bridge. Some Precolumbian residents altered vegetation immediately after first arrival at least 11,000 years ago, and began to add domesticated crops to their subsistence inventory between 9000 and 7000 BE Maize and manioc (or cassava), domesticated outside the land bridge, were introduced in Preceramic times, early in the period between 7000 and 4500 BP, and gradually dominated regional agriculture as they became more productive, and as human populations increased and spread into virgin areas. Diversity in material culture is visible ca. 6000 BP, and becomes more apparent after the introduction of pottery ca. 4500 BE By 2000 BP culture areas with distinctive artifact inventories are discernible. Between 2500 and 1300 BP hierarchies among regions, sites, social groups, and individuals point to the establishment of chiefdoms whose elite members came to demand large numbers of costume and sumptuary goods. A few special centers with stone sculptures and low-scale architecture served a social universe larger than the chiefdom, such as clusters of recently fissioned social groups with memories of a common heritage. Social interactions on the land bridge, endowed with productive bottomlands, highland valleys, and coastal habitats, appear always to have been strongest among neighboring groups.