Although the existence of conclusive data on how and when Mesoamerica was first populated is still lacking in substance , it is generally accepted that the first people to arrive in the New World did so around 18,000 years ago. Sometimes data suggests that premodern humans may have arrived in America before 16,000 BCE, but these conclusions are largely speculative or based on data that cannot be corroborated. It is unclear whether the migration took place as a single event or whether it occurred in several waves. Regardless, there are a few important theories about how genetically modern humans were able to make the last great migration from the Old World to the Americas. Regardless, despite our obscure understanding of how humans arrived in Mesoamerica, it is clear that once there, human civilization and culture was not only able to persist, but also to thrive. in a set of conditions unique to the region. The understood theory of humanity's beginnings in the Americas involves a land bridge that would have "spanned across what is now the Bering Strait and connected northeastern Siberia to Alaska." A migration of this type would necessarily have occurred before 9,500 BCE, during the Earth's last glacial maximum. During this ice age, sea levels would have been relatively low, exposing areas of Beringia currently underwater. This land bridge – as it is often called – would have been home to large herds of several species of megafauna, such as mammoths, bison and horses. Paleolithic hunters and gatherers could easily have followed these herds out of the Eurasian tundra and into North America. An alternative theory suggests that humans may have traveled to the Americas... middle of paper ...... several major epicenters of commerce and culture. They were well on their way to becoming a fully actualized civilization and a center of Mesoamerican culture.BibliographyAdams, Richard E. Ancient Civilizations of the New World. Boulder, Colorado: Westview Press, 1997. Adams, Richard E. Prehistoric Mesoamerica. Boston: Little, Brown, 1977. Flannery, Kent V. “Archaeological Systems Theory and Early Mesoamerica.” Anthropological archeology in the Americas. (1968). http://www.neiu.edu/~circill/hageman/anth396/archaeologicalsystems.pdf (accessed March 17, 2014). MacNeish, Richard S. “Ancient Mesoamerican Civilization.” SCIENCE. No. 3606 (1964). http://www.clas.ufl.edu/users/dcgrove/mexarchreadings/ancient.pdf (accessed March 17, 2014). Scarre, Christopher. The human past: global prehistory and the development of human societies. New York: Thames and Hudson, 2013.