Energetics and the Origin of Modern Humans

Ontogenetic scaling of the human nose in a longitudinal sample: Implications for genus Homo facial evolution

“…During the Pleistocene, the genus Homo experienced a significant reduction in body mass, with archaic Homo (e.g., H. neanderthalensis, H. heidelbergensis) generally characterized by greater body mass estimates compared to fossil and recent H. sapiens (Ruff et al, 1997(Ruff et al, , 2005Churchill et al, 2012;Froehle et al, 2013). While the causal mechanisms associated with this trend in size reduction are incompletely understood, researchers have repeatedly shown that as a result of body mass differences, the basal metabolic rate and DEE of archaic Homo would have exceeded those of early modern and recent H. sapiens (e.g., Sorensen and Leonard, 2001;Aiello and Wheeler, 2003;Churchill, 2006;Cartmill and Smith, 2009;Froehle and Churchill, 2009;Froehle et al, 2013). As a result, archaic Homo would have had substantially higher requisite oxygen demands when compared to modern H. sapiens.…”

“…Researchers have hypothesized that variation in nasal morphology, both in archaic Homo and in recent humans, is influenced by body mass and associated oxygen consumption demands required for tissue maintenance Froehle et al, 2013). The present study contributes to our understanding of this potential developmental and functional dynamic by assessing sexual dimorphism in nasal cavity size in a longitudinal recent human sample in order to (a) assess sexual dimorphism in the nasal cavity in recent humans and determine when during ontogeny male-female differences in nasal cavity size appear; and (b) determine if there are significant differences in nasal/body size scaling relationships in males and females during ontogeny.…”

“…For example, researchers have hypothesized that larger facial dimensions in archaic Homo are due, in part, to greater nasal cavity dimensions required to facilitate the necessary oxygen intake needed to maintain a larger body mass (Cartmill and Smith, 2009;Yokley et al, 2009;Froehle et al, 2013). Consequently, temporal patterns of facial size reduction in genus Homo (e.g., Trinkaus, 2003;Holton and Franciscus, 2008;Pearson, 2008;Maddux and Franciscus, 2009) may be tied, at least in part, to body mass reduction and reduced daily energy requirements.…”

“…In particular, researchers have underscored the potential effects of these variables on the size of the nasal cavity Froehle et al, 2013). Thus, while there is evidence to suggest that the nasal region may be somewhat modularized with regard to other aspects of craniofacial morphology such as the lateral facial skeleton and the dentognathic region (Chierici et al, 1973;Ant on, 1989; Ackermann, 2005;Polanski and Franciscus, 2006;Rhode and Arriaza, 2006;Holton and Franciscus, 2008;Mitteroecker and Bookstein, 2008), nasal skeletal form may be more tightly integrated with other components of the respiratory system (e.g., Enlow, 1990;Rosas and Bastir, 2002;Hall, 2005;Bastir, 2008;Yokley et al, 2009;.…”

“…Therefore, our goal is to examine the ontogeny of sexual dimorphism of nasal cavity size using longitudinal cephalometric and anthropometric data from the Iowa Facial Growth Study. If nasal cavity size is tied to variation in body size/composition and ultimately energetic requirements (e.g., Enlow, 1990;Bastir, 2008;Yokley et al, 2009;Froehle et al, 2013), we make the following predictions. First, male-female differences in nasal cavity size will appear during early adolescence and correspond to the appearance of sexual dimorphism in body composition.…”