With National Science Foundation support Dr. Bruce Benz will conduct detailed analyses of maize (Zea mays L. subsp. Mays) collected in archaeological excavations in the Tehuacan region and in Ocampo Cave, Mexico. Through the study of its evolution he plans to document the complementary roles of intentional human selection and environmental inducement in the domestication of maize and its emergence as the principal staple in Mesoamerica from ca. 4700 years ago until the time of the Spanish Conquest. Through detailed morphometric analysis, radiocarbon dating and oxygen and hydrogen isotopic analysis of selected samples he will address the following questions: 1. During what time periods did morphological change occur and how fast or slow did the maize ear change in shape and productivity during the period ca. 3500 BC to AD 1500? 2. What proportion of morphological change in the maize ear can be attributed to natural selection and what proportion to random genetic drift? 3. What effect did fluctuations in temperature and effective moisture have on maize's morphological change and productivity? 4. At what time and for what reasons did subsequent diversification processes operate to give rise to the numerous extant races of Mexican maize?
The "Neolithic Revolution" - the domestication of plants and animals - constituted a fundamental turning point in human development because the productivity and reliability of these resources provided the stable subsistence base which gave rise to complex societies and civilization. In the North and Middle America maize, in conjunction with squash and beans, provided the basis for this change and therefore understanding the processes with led to its domestication is essential for reconstructing how prehistoric societies developed. Evidence to date indicates that maize was domesticated in Middle America and subsequently spread both North and South. While abundant well preserved samples have been recovered in cave sites in Mexico much of this material remains unstudied and Dr. Benz's examination of several stratigraphic sequences and their synthesis will constitute a major research contribution. Many researchers, biologists and archaeologists alike, wish to understand the interactions among plant species, human behavior and environment (changes in temperature and rainfall) which resulted in the apparently independent domestication of many species at roughly the same time in many parts of the world and thus the potential significance of Dr. Benz's research is broad.
