Biological Adaptation of Man to His Environment: Heat, Cold, Altitude, and Nutrition

Abstract

In meeting the challenge of the climatic extremes of heat and cold and the geographic extreme of high altitude man, like other animals, has the principal problem of maintaining his operating equilibrium. In nutritional terms there is a necessary metabolic balance to be accomplished. Beyond cultural paraphernalia and know-how, adjustments to maintain balance are accomplished by the bodily physiology, which is itself reflected in morphology. In very large part these physiological and morphological adjustments represent continuous variables of probably complex reactive origins. Consequently they are assumed to be under polygenic control. For this reason the evolutionary model, based as it is on the behavior of single alleles, is applicable only with extensive modifications to the human traits responding to heat, cold, altitude, and dietary stresses. In these traits, mutation and drift should have less discernible effect. Homozygosity and heterozygosity have different and lesser meanings, at least within the breeding patterns common in man. Selection and its product of adaptation, however, can operate rapidly in polygenic traits, particularly with the loading of linkage and recombination.To a considerable extent, however, variation in these polygenic traits falls outside the evolutionary model because of the range of nongenic plasticity responses in man. It may be, as Hulse (1960) suggests, that the individual range of plasticity response is genetically based and that ranges differ within and between human populations.

Gough's Cave 1 (Somerset, England): an assessment of body size and shape

“…In living populations, the weight: height, or ponderal, index is used as a measure of this relationship (e.g., Newman, 1961;Schreider, 1964Schreider, , 1975Eveleth, 1966;Hiernaux et al, 1975). This relationship is most easily quantified skeletally via relative femoral head size (i.e., antero-posterior femoral head diameter/femoral bicondylar length × 100).…”

Morphological adaptation to climate in modern and fossil hominids

“…Both Barnicot (1959) and Newman (1970) felt that an open savanna environment was the most likely habitat within which hominids evolved the extremely proficient mechanism of evaporative cooling via sweating characteristic of all living humans. Both authors also noted the problem of virtual hairlessness in hominids in creating greater potential for direct absorption of solar radiation.…”

“…The complexity of human climatic adaptation and the need to consider interactions with other factors, such as nutrition and culture, and to take into account nonmorphological adaptations, were stressed by several researchers writing around 1960 (Barnicot, 1959;Baker, 1960;Newman, 1960-61). These themes were further elaborated and strengthened during the growth of human ecology and particularly the International Biological Program during the late 1960s (Lasker, 1969;Weiner, 1977).…”

Body proportions of circumpolar peoples as evidenced from skeletal data: Ipiutak and Tigara (Point Hope) versus Kodiak Island Inuit

“…Specifically, two empirically derived ecogeographical rules, those of Bergmann (1847) and Allen (1877), state that within a widespread endothermic species, those in colder regions will tend to weigh more (Bergmann's rule) and be characterized by shorter appendages (Allen's rule) than their conspecifics in warmer climes. Humans show strong patterning suggestive of their adherence to these rules (Coon et al, 1950;Newman and Munro, 1955;Baker, 1960;Newman, 1953Newman, , 1960Newman, , 1961Coon, 1962;Schreider, 1950Schreider, , 1964Schreider, , 1975Roberts, 1953Roberts, , 1978Crognier, 1981;Trinkaus, 1981;Pearson, 2000a,b;Ruff, 1991Ruff, , 1994Ruff, , 2002Holliday, 1997aHolliday, ,b, 2005. In particular, it has long been recognized that circumpolar peoples (e.g., Inuit, Aleuts, Sá mi) have more foreshortened limb segments and broader trunks and are heavier on average than populations at even the mid-latitudes (Trinkaus, 1981;Ruff, 1994;Holliday, 1997b).…”