Agriculture has long been regarded as an improvement in the human condition: Once Homo sapiens made the transition from foraging to farming in the Neolithic, health and nutrition improved, longevity increased, and work load declined. Recent study of archaeological human remains worldwide by biological anthropologists has shown this characterization of the shift from hunting and gathering to agriculture to be incorrect. Contrary to earlier models, the adoption of agriculture involved an overall decline in oral and general health. This decline is indicated by elevated prevalence of various skeletal and dental pathological conditions and alterations in skeletal and dental growth patterns in prehistoric farmers compared with foragers. In addition, changes in food composition and preparation technology contributed to craniofacial and dental alterations, and activity levels and mobility decline resulted in a general decrease in skeletal robusticity. These findings indicate that the shift from food collection to...

Biological changes in human populations with agriculture

The analysis of humeral asymmetry in Recent human skeletal samples and an extant tennis-player sample documents minimal asymmetry in bone length, little asymmetry in distal humeral articular breadth, but pronounced and variable asymmetry in mid- and distal diaphyseal cross-sectional geometric parameters. More specifically, skeletal samples of normal modern Euroamericans, prehistoric and early historic Amerindians, and prehistoric Japanese show moderate (ca. 5-14%) median asymmetry in diaphyseal cross-sectional areas and polar second moments of area, whereas the tennis-player sample, with pronounced unilateral physical activity, exhibits median asymmetries of 28-57% in the same parameters. A sample of Neandertals with nonpathological upper limbs exhibits similarly low articular asymmetry but pronounced diaphyseal asymmetries, averaging 24-57%. In addition, three Neandertals with actual or possible post-traumatic upper limb alterations have the same low articular asymmetry but extremely high diaphyseal asymmetries, averaging 112-215%. These data support those from experimental work on animals, exercise programs of humans, and human clinical contexts in establishing the high degree of diaphyseal plasticity possible for humans, past and present, under changing biomechanical loading conditions. This lends support to activity-related functional interpretations of changing human diaphyseal morphology and robusticity during the Pleistocene.

Postcranial robusticity in Homo. II: Humeral bilateral asymmetry and bone plasticity

Sexual dimorphism in human lower limb bone structure: relationship to subsistence strategy and sexual division of labor

Biomechanical Analyses of Archaeological Human Skeletons

A growing body of archeological evidence suggests that the dramatic climatic events of the Last Glacial Maximum in Europe triggered important changes in foraging behavior, involving a significant decrease in mobility. In general, changes in mobility alter patterns of bending of the midshaft femur and tibia, resulting in changes in diaphyseal robusticity and shape. This relationship between levels of mobility and lower limb diaphyseal structure was used to test the hypothesized decrease in mobility. Cross-sectional geometric data were obtained for 81 Upper Paleolithic and Mesolithic European femora and tibiae. The sample was divided into three time periods: Early Upper Paleolithic (EUP), Late Upper Paleolithic (LUP), and Mesolithic (Meso). In addition, because decreased mobility often results in changes in sex roles, males and females were analyzed separately. All indicators of bending strength decrease steadily through time, although few of the changes reach statistical significance. There is, however, a highly significant change in midshaft femur shape, with LUP and Meso groups more circular in cross-section than the EUP sample, supporting archeologically based predictions of decreased mobility. Sexual dimorphism levels in diaphyseal strength remain low throughout the three time periods, suggesting a departure in Upper Paleolithic and Mesolithic foragers away from the pattern of division of labor by sex observed in modern hunter-gatherers. Results confirm that the onset of the Last Glacial Maximum represents a crucial stage in Late Pleistocene human evolution, and signals the appearance of some of the behavioral adaptations that are usually associated with the Neolithic, such as sedentism.

Mobility in Upper Paleolithic and Mesolithic Europe: Evidence from the lower limb

Diachronic patterns of change in the femoral diaphysis are examined in archaeological skeletal samples from the American Southwest. Three cultural periods differing in subsistence-settlement strategies are represented: Early Villages (A.D. 500-1150), Abandonments (A.D. 1150-1300), and Aggregated Villages (A.D. 1300-1540). Relevant properties of cross-sectional geometry and bone density were obtained using computerized tomography. Temporal trends in geometry suggest that activity levels increased between Early Villages and Abandonments, then declined during Aggregated Villages. In both sexes, femoral shape became more circular, and bending stresses were reduced in the a-p plane through time. Compared to the other periods, bone density was the lowest during Abandonments in both sexes. The reduction in bone density may reflect declining nutritional quality through time that was especially poor during the Abandonments period. Patternings in sexual dimorphism suggest that Abandonments males may have been more sensitive to nutritional stress than contemporary females.

Sharon L. Brock

Papers

Diachronic patterns of change in structural properties of the femur in the prehistoric American Southwest