Trying to fathom farming's origins
Tuesday, August 14, 2007 3:22 AM
By Bradley T. Lepper
Tom Dillehay, an archaeologist with Vanderbilt University, and several colleagues announced last month in the journal Science that they had recovered remarkably early evidence for agriculture in South America.
Working at several sites in the Nanchoc Valley of northern Peru, they found squash seeds that were more than 9,000 years old. This is nearly twice as old as previously reported farming evidence in the region.
Dillehay and his co-authors point out that one of the most important aspects of this discovery is that "horticulture and cultural complexity developed in the Americas nearly as early as it did in many parts of the Old World."
Why should this be surprising?
Given that the civilizations of the Old and New Worlds developed independently, there is no reason to expect that peoples on opposite sides of the globe all would adopt agriculture within a short period of time.
And yet, we've known for some time that they did. Mark Nathan Cohen, anthropologist at the State University of New York, Plattsburg, wrote in 1977 that "the problem is not just to account for the beginnings of agriculture, but to account for the fact that so many human populations made this economic transition in so short a time."
The discoveries made by Dillehay and his colleagues make this problem more acute by considerably shortening the span of time involved from 4,000-5,000 years to 2,000-3,000 years.
For Cohen, the near-global synchrony of the origins of agriculture meant that understanding how and why people all suddenly turned to farming required a global explanation.
He proposed that a rapidly growing human population spread throughout the world. Continuing population growth put stress on local food supplies, which, in turn, led to farming as a way of artificially boosting food production.
Not all archaeologists agree that a global explanation is necessary. Certainly, an understanding of the problem must be based on detailed studies of local archaeological sequences, such as Dillehay and his colleagues are providing.
Bradley T. Lepper is curator of archaeology at the Ohio Historical Society.
blepper@ohiohistory.orghttp://www.dispatch.com/dispatch/content/science/stories/2007/08/14/sci_lepper14.ART_ART_08-14-07_B5_2M7ILI3.html
