Human social inequality is known to impact health outcomes, often through socioeconomically linked nutritional disparities. Differential access to particular types and amounts of food has been demonstrated by archaeological examinations and stable isotope analyses throughout Classic Period Mesoamerica. The results of these studies have suggested that Mesoamerican elites were granted greater access to maize and meat relative to commoners during the Classic Period. Stable oxygen isotope studies have served to further elucidate issues of migration and social interaction in Classic Period Mesoamerica by aiding in defining marriage patterns, understanding how migration relates to social status, and identifying the geographic origins of sacrifice victims. Few studies of Pre-Classic human remains from central Mexico have employed stable isotope analyses. The present study employs stable oxygen, carbon, and nitrogen isotopes in order to understand dietary behaviors, status differences, and migration patterns at the complex Formative Period site of Chalcatzingo in Morelos, Mexico. Stable carbon and nitrogen isotope results suggest that both elites and commoners consumed large amounts of maize and similar amounts of animal protein. There was no significant difference between commoners and elites in terms of dietary behaviors. Stable oxygen isotope results differed from previously reported values for central Mexico, potentially suggesting that Chalcatzingo was a community composed of a number of migrants. There was no statistically significant difference between elites and non-elites in terms of oxygen stable isotope values. The social stratification at this site evidently did not result in substantial differences in dietary behaviors or migration patterns between elites and commoners, suggesting that factors other than socioeconomic status and archaeological evidence must be taken into account when considering how such behaviors were mediated in the past.

This dissertation explores the link between habitat and human evolution by

examining the mosaic habitat and its seasonal variation in rainfall at the single fossil

locality of Allia Bay, Kenya (3.97±0.03 MA) using stable carbon (δ13C) and oxygen

(δ18O) isotope ratios in fossil faunal tooth enamel. Serial δ18O values from 10μm spot

analyses in contrast to data from bulk powdered samples, this dissertation uses browsing and grazing faunal enamel to document prolonged periods of environmental stability with mild seasonality and periods of marked fluctuating seasonality during the drier phases at Allia Bay when Au. anamensis occupied the region.

Traditional bulk δ13C and δ18O values of fossil Allia Bay compared to modern

Koobi Fora fauna indicate that the local environment at Allia Bay was distinctly wetter

and more closed compared to the arid open grassland of the modern region. Despite

regional interpretations of a continuously arid open Turkana Basin over the past 4 Ma,

the Allia Bay fauna suggest that local habitats surrounding Lake Turkana were

ecologically distinct with different microclimates. Enamel from fossil localities used for

isotopic analysis to reconstruct the paleoenvironment are often considered impervious to

diagenesis, however at Allia Bay mineral structure changes in enamel indicate that

diagenesis is an issue at this fossil locality. While the complex process of enamel

diagenesis is not understood completely, the high-resolution sampling of δ18Oen values

documented a relationship between mineral structure change and diagenesis of δ18Oen. Confocal laser fluorescent microscopy imaging identified evidence of mineral structure change documented by far-red fluorophores that correlate with alteration of δ18Oen, while other inclusions identified by green and red fluorophores have limited impact to δ18Oen. Ultimately, this dissertation documented the first evidence of variation in seasonal rainfall patterns at Allia Bay during intra-annual cycles (~10-17 months of time recorded in enamel). The δ18Oen values documented in fossil hippopotamids and suids show a 6-8‰ baseline difference during the occupation of Allia Bay, suggesting the ecosystem shifted significantly. As rainfall patterns fluctuated, animal and plant communities were impacted and the early hominins would have required adaptive flexibility to cope with the changing habitat.

Despite emphasis placed by transnational theorists on the uniqueness of contemporary connections to homeland, such theories are relevant to the expansion of the ancient Tiwanaku state into the Osmore Drainage of southern Peru. These archaeological connections to homeland were maintained in the broader context of Tiwanaku sociopolitical organization, understanding of which is advanced by recent approaches to inter-regional interaction emphasizing studies of heterogeneous identities in peripheral contexts. The present study employs radiogenic strontium isotope analysis and stable carbon and nitrogen isotope analysis of bone collagen from individuals buried at a Tiwanaku provincial center in comparison with published diet and mobility data to better understand how different communities engaged with their ethnic and broader political identities. Additionally, radiogenic strontium isotope analysis of architectural material from the same provincial center is used to determine its source location and to better understand how the construction of the provincial center’s temple related to colonists’ ethnic and/or broader sociopolitical identities. Overall, a lack of difference in diet and mobility practices between different colonial communities and the building material’s origin in the Osmore Drainage supports more heterarchical notions of Tiwanaku colonial organization, as well as concepts of Tiwanaku as both a political entity and a deeply held cultural milieu. Moreover, the presence of an anomalous young woman suggests the possible exchange of marriage partners with coastal Huaracane-related populations, an intriguing mechanism for the poorly understood indirect procurement of marine resources by Tiwanaku colonists.