The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Fire and Tools: combining animal and human experiments to study food processing and cranio-dental integration

KATHERINE D. ZINK and DANIEL E. LIEBERMAN.

Human Evolutionary Biology, Harvard University

Friday 3:00-3:15, Galleria South Add to calendar

How has food processing affected human cranio-dental morphology and integration? Here we test the hypothesis that food processing has led to a reduction of both cranial and dental size and in modern, urban societies has produced a less integrated cranio-dental complex. We also discuss the necessity of combining controlled animal experiments with comparative human studies to test integration hypotheses. Experiment 1: Cranio-dental morphology of two human skeletal populations, one agricultural (dated ~1531-1831) and one more modern and urban (dated ~1910-1988), was quantified with 3-D landmark and 2-D caliper measurements. Early results indicate that dietary changes, presumably to more processed foods, have decreased skull size and increased shape variance. Experiment 2: Eight 6-week-old standard pigs were fed either a hard (normal chow) or soft (water-softened chow) diet ad libitum and received bi-monthly injections of Calcein, a fluorescent mineral label. After 12 weeks, the animals were sacrificed, skulls cleaned and M1 and M2 sectioned. Results suggest that consuming softer food changes skull shape, reduces corpus size and slows dentin secretion rates (which may result in smaller teeth). Together, these two complimentary studies support our hypotheses and highlight the importance of combining animal models with human studies to test human evolutionary theories.

This study was funded by the American School for Prehistoric Research and the National Science Foundation (DDIG # 0925688).

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