Doctoral Dissertation Research: The Interactive Influence of Environment and Energetics on Human Morphology

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As the nose is responsible for heating and humidifying air before it enters the lungs, geographically-patterned variation in nasal morphology has long been attributed to climatic adaptation. However, previous research has also shown that the nose must be large enough to take in a sufficient amount of oxygen during each breath to meet life-sustaining metabolic requirements. Accordingly, this doctoral dissertation project examines the combined effects (and possible functional trade-offs) of demands for respiratory air-conditioning and oxygen intake on the nasal complex during human evolution. By explicitly investigating climatic adaptation in nasal morphology within the context of human body size and shape, this study helps address how different anatomical systems have co-evolved in response to environmental pressures. Computed tomography (CT) scans generated for this project will be made freely available to other researchers through established online archives, substantially expanding the geographic/temporal diversity of CT scans currently available to anthropologists and the broader scientific community. This research also provides training opportunities for undergraduate and medical students (including those from under-represented groups) and the investigator will incorporate project findings into ongoing public outreach initiatives including K-12 science education programs, museum-based community engagement, public lectures, and online podcasts.Despite substantial evidence that both climatic and metabolic pressures have likely influenced human nasal anatomy, the interplay of these two factors on nasal size and shape during human evolution is not fully understood. This study employs a "whole-body" approach by quantifying variation in cranial and post-cranial skeletal morphology in a large, geographically- and temporally-diverse sample of recent and fossil Homo. Using established equations, body mass and basal metabolic rate will then be calculated from post-cranial measurements and employed in conjunction with nasal and climatic variables to statistically assess whether: (1) nasal morphology exhibits stronger associations with metabolic demands than other aspects of the craniofacial complex; (2) climate and metabolic demands differentially influence particular aspects of nasal morphology; and (3) deviations from climatically predicated nasal morphology in fossil Homo (particularly Neanderthals) are attributable to greater energetic requirements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.