Human body size and limb proportions can provide important information about adaptation, population movements, and health disparities. This study investigated changes in body size and limb proportions of adult Egyptians temporally and geographically in relation to climatological, sociopolitical and economic developments. It was predicted that Egyptian groups that experienced more environmental stress would be shorter and exhibit less sexual dimorphism. It was also predicted that Egyptians would be intermediate between higher and lower latitude populations in body form and limb length ratios. The main skeletal sample consisted of 492 males and 528 females, all adults from the Predynastic and Dynastic Periods, a time spanning c. 5500 BCE-600 CE. Egyptian body dimensions were compared to Nubian groups, as well as to modern Egyptians and other higher and lower latitude populations. The present study found a downward trend in ancient Egyptian stature for both sexes through time, as well as decreased sexual dimorphism in stature. The decreases may be associated with dietary and social stress with the intensification of agriculture and increased societal complexity. Modern Egyptians in the study's sample are generally taller and heavier than their predecessors; however, modern Egyptians exhibit relatively lower sexual dimorphism in stature. Ancient Egyptians have more tropically adapted limbs in comparison to body breadths, which tend to be intermediate when plotted against higher and lower latitude populations. These results may reflect the greater plasticity of limb lengths compared to body breadth. The results might also suggest early Mediterranean and/or Near Eastern influence in Northeast Africa.

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第19086号 / 人博第739号 / 新制||人||177(附属図書館) / 26||人博||739(吉田南総合図書館) / 32037 / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 瀬戸口 浩彰, 教授 加藤 眞, 教授 市岡 孝朗 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM

No description available.

The hand has the highest surface area-to-volume ratio of any body part. This property offers the potential for the hand to serve an important function in thermoregulation through radiative heat loss. Theoretically, the capacity for heat loss may be influenced by hand and digit proportions, but the extent to which these proportions influence the hand's radiative properties remains under-investigated. Although hand morphology is highly constrained by both integration and functional dexterity, phenotypic variation in hand and digit proportions across human populations shows broad ecogeographic patterns. These patterns have been associated with climate adaptation. However, the theory linking climate adaptation to such ecogeographic patterns is based on underlying assumptions relating to thermodynamic principles, which have not been tested in vivo. This study sought to determine the influence of hand and digit proportions on heat loss from the hands directly, the additional anthropometric factors that may affect this relationship, and the impact of variation in hand proportions on dexterity in the cold. The relationship between hand proportions and thermoregulation was tested through both laboratory-based investigation and a field study. The laboratory investigation assessed the relationship between hand proportions and heat loss, the influence of body size and composition on this relationship, and the effect of morphological variation on manual dexterity. Participants (N=114; 18-50 years of age), underwent a 3-minute ice-water hand-immersion. Thermal imaging analysis was used to quantify heat loss. Hand and digit proportions were quantified using 2D and 3D scanning techniques; body size and composition were measured using established anthropometric methods and bio-impedance analysis. After accounting for body size, hand width, digit-to-palm length ratio, and skeletal muscle mass were significant predictors of heat loss from the hand, whilsthand length and fat mass were not. A separate set of participants (N=40) performed a Purdue pegboard dexterity test before and after the immersion test, which demonstrated that digit width alone negatively correlated with dexterity. The field study tested whether phenotypic variation in upper limb proportions could be attributed to cold adaptation or selection for dexterity in living populations exposed to significant energetic stress. Upper limb segment lengths were obtained from participants (N=254; 18-59 years of age), from highland and lowland regions of the Nepalese Himalayas using established anthropometric methods, and relative hand proportions were assessed in relation to severe energetic stress associated with life at high altitude. Relative to height, hand length and hand width were not reduced with altitude stress, whilst ulna length was. This indicates that cold adaptation is not shaping hand proportions in this case, although phenotypic variation in other limb segments may be attributed to cold adaptation or a thrifty phenotype mechanism. The current study provides empirical evidence to support the link between surface area-to-volume ratio, thermodynamic principles and ecogeographical patterns in human hand morphology. However, this research also demonstrates the complexity of the hand's role in thermoregulation; not only do other factors such as muscularity affect heat loss from the hand, but hand morphology is also highly constrained by integration and dexterity.