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Adaptation to Arctic climate in the native populations of North-East Asia: comparing body morphology and craniometric dataтезисы доклада
- Авторы: Berdieva A., Evteev A.
- Сборник: Abstracts. European Society for the study of Human Evolution meeting.Bordeaux, September 2012
- Тезисы
- Год издания: 2012
- Место издания: Bordeaux
- Первая страница: 40
- Последняя страница: 40
- Аннотация: The native population of the Chukchi Peninsula have lived in relative isolation in a very harsh environment from II-I millennia BC (Dikov, 1977) and have evolved a stable morpho-functional complex (Alekseeva et al., 2008). We assessed variability of a set of anthropometric characteristics in a sample of 170 male Chukchi and 58 Siberian Inuit aged between 18 and 59 years. The data were collected between 1970 and 1982 during expeditions led by V.P. and T.I. Alekseev. Our results have confirmed the traits attributed to an “arctic adaptive type” (Alekseeva, 1986) but have also provided some new insights. Both groups have high body mass, low stature, large circumferences and decreased skin fold thickness. Thy have a massive build, particularly in the upper part of the body, with a large cylindrical ribcage, large volume of the medullary cavities and a relatively thin compact layer in the long bones. thus, there is a well-defined complex of skeletal features likely having an adaptive value. It is believed that the complex has formed due to specific respiratory needs: because of “Arctic hypoxia” both the bloodstream velocity and respiratory muscle tonus are increased. Change in size and shape of the ribcage might have been a consequence. Compared to populations from temperate climate zones, the degree of variation of anthropometric characteristics is decreased. In Siberian Inuit relative to Chuchki, this complex of adaptive features is more pronounced and there is even less variation, demonstrating a kind of “extreme” of Arctic adaptation. There are differences in body morphology between the samples depending on the how extreme the environment. In areas with milder conditions there is a decrease in body fat percentage, shoulder and buttock circumferences and chest index. Previous researches have demonstrated that among Arctic groups increasing environmental harshness is correlated with increases in head and face sizes, widening of the ribcage, decrease in stature and body fat percentage, changes in a number of physiological parameters.The very specific craniofacial morphology of Siberian Inuit already existed at the turn of the Common Era (Debets, 1975). One of the features contrasting them with continental Siberian groups is narrow piriform aperture. It has been demonstrated that this feature likely has an adaptive value (Wolpoff, 1968; Harvati, Weaver, 2006). A study by of one of the co-authors (AE) showed that Siberian Inuit share with other Northern Siberian groups the general pattern of a cold-adapted facial skeleton. But Inuit show significant narrowing of the anterior nasal cavity and nasal aperture. These morphological features are significantly correlated with increased precipitation during the winter months. Both narrowing-lengthening of the nasal cavity and narrowing of the piriform aperture lead to increase in turbulence of air inflow, slowing the airstream and it in turn increasing loading experienced by the respiratory muscles (Churchill et al., 2004). These two features are strongly pronounced in Siberian Inuit and, taking into account low oxygen partial pressure we suggest that the large size and peculiar shape of Inuit ribcages are to some extent related to the highly derived upper airway morphology.
- Добавил в систему: Евтеев Андрей Алексеевич