Alexa Pennavaria Kelly

Ecogeographic variation in nasal morphology provides strong evidence for climatic adaptation across humans, likely reflecting variable demands for warming and moisturizing inspired air (i.e., air conditioning capacity) in different environments. However, the nose must also intake a sufficient amount of air during each breath to meet fundamental metabolic demands for oxygen. Yet, despite substantial evidence that both climate and metabolism likely influence nasal anatomy, virtually no research has investigated the interplay of these two factors on nasal size and shape. The proposed study will examine the combined effects (and possible physiological trade-offs) of the demands for respiratory air conditioning and oxygen intake on the nasal complex during human evolution. This will be accomplished by collecting 3D landmark data from the nasal skeleton, and linear measurements from associated post-cranial elements, across geographically- and temporally-diverse samples 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 climatic variables to assess their potential physiological and evolutionary influences on geographic/temporal variation in nasal size and shape. This enhanced understanding of human nasal variation will thus contribute valuable insights into broader patterns of climatic adaptation during human evolution.