Remarks on the environmental adaptation of man

Walter, H.

doi:10.1007/bf00295790

Cited by 27 publications

(17 citation statements)

References 11 publications

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“…Anthropologists have long noted geographical variation in body morphology and speculated about its relation to the local environment. 16 Over 150 y ago Bergmann proposed the general rule that body size in mammalian species increases from warmer to cooler climates. 17 Although this variability is commonly attributed to genetic differences, 16 studies in animals and humans raise the possibility that environmental temperature per se may play a contributory role.…”

Section: Introductionmentioning

confidence: 99%

“…16 Over 150 y ago Bergmann proposed the general rule that body size in mammalian species increases from warmer to cooler climates. 17 Although this variability is commonly attributed to genetic differences, 16 studies in animals and humans raise the possibility that environmental temperature per se may play a contributory role. In a study of American-born, Caucasian males conducted nearly 50 y ago, Newman and Munro demonstrated an inverse relation between weight for height and the average January temperature in the state of birth.…”

Section: Introductionmentioning

confidence: 99%

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Birth weight, climate at birth and the risk of obesity in adult life

2000

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OBJECTIVE: To determine whether obesity in adults is related to seasonal or climatic conditions around the time of birth. SUBJECTS: 1750 men and women born in Hertfordshire between 1920 and 1930. MEASUREMENTS: Height and weight measured in the home by trained ®eldworkers. RESULTS: Body mass index (BMI) rose with increasing birth weight in men and women. In men, BMI and the prevalence of obesity (BMI ! 30 kgam 2 ) varied as a function of month of birth and was greater among those born in January ± June than among those born in July ± December. The relationship between birth weight and adult obesity was also stronger in those born in the ®rst 6 months of the year or following cold winters than in those born in the last 6 months of the year or following mild winters. CONCLUSIONS: These ®ndings suggest that adult obesity is linked both to high birth weight and to early cold exposure. Consequently, exposures in early life may contribute to individual variation in susceptibility to obesity in adults.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Birth weight, climate at birth and the risk of obesity in adult life

2000

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“…Allen's rule states that, ''in warm-blooded species, the relative size of exposed portions of the body decreases with decrease of mean temperature'' (Allen, 1877). It has long been suggested that the ecological rules may apply to humans (Ridgeway, 1908;Schreider, 1950Schreider, , 1957Schreider, , 1964Schreider, , 1971Schreider, , 1975Roberts, 1953Roberts, , 1973Roberts, , 1978Barnicot, 1959;Baker, 1966;Walter, 1971;Ruff, 1994).…”

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confidence: 98%

Climatic influences on human body size and proportions: Ecological adaptations and secular trends

Katzmarzyk

Leonard

1998

Am. J. Phys. Anthropol.

314

184

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This study reevaluates the long-standing observation that human morphology varies with climate. Data on body mass, the body mass index [BMI; mass (kg)/stature (m)2], the surface area/body mass ratio, and relative sitting height (RSH; sitting height/stature) were obtained for 223 male samples and 195 female samples derived from studies published since D.F. Roberts' landmark paper "Body weight, race, and climate" in 1953 (Am. J. Phys. Anthropol. 11:533-558). Current analyses indicate that body mass varies inversely with mean annual temperature in males (r=-0.27, P < 0.001) and females (r=-0.28, P < 0.001), as does the BMI (males: r=-0.22, P=0.001; females: r=-0.30, P < 0.001). The surface area/body mass ratio is positively correlated with temperature in both sexes (males: r=0.29, P < 0.001; females: r=0.34, P < 0.001), whereas the relationship between RSH and temperature is negative (males: r=-0.37, P < 0.001; females: r=-0.46, P < 0.001). These results are consistent with previous work showing that humans follow the ecological rules of Bergmann and Allen. However, the slope of the best-fit regressions between measures of body mass (i.e., mass, BMI, and surface area/mass) and temperature are more modest than those presented by Roberts. These differences appear to be attributable to secular trends in mass, particularly among tropical populations. Body mass and the BMI have increased over the last 40 years, whereas the surface area/body mass ratio has decreased. These findings indicate that, although climatic factors continue to be significant correlates of world-wide variation in human body size and morphology, differential changes in nutrition among tropical, developing world populations have moderated their influence.

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“…Rather, it was natural selection that produced the conspicuous gradient of skin tones groups observed in our species. Samuel Stanhope Smith's observation of a correlation between latitude, solar processes, and human skin pigmentation was refined in the latter part of the 20th century when it was demonstrated that human skin reflectance (as a measure of skin pigmentation) was more highly correlated with latitude as a surrogate for UVR than with temperature, humidity, or altitude (15,16). The introduction of geographic information systems (GIS) technology and the availability of remotely sensed environmental data permitted accurate and precise testing of the strength of the relationship between physical parameters of the environment and skin pigmentation, and demonstrated conclusively the high correlation between skin pigmentation and UVR (7,17).…”

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confidence: 99%

Human skin pigmentation as an adaptation to UV radiation

Jablonski

Chaplin

2010

Proc. Natl. Acad. Sci. U.S.A.

588

576

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Human skin pigmentation is the product of two clines produced by natural selection to adjust levels of constitutive pigmentation to levels of UV radiation (UVR). One cline was generated by high UVR near the equator and led to the evolution of dark, photoprotective, eumelanin-rich pigmentation. The other was produced by the requirement for UVB photons to sustain cutaneous photosynthesis of vitamin D 3 in low-UVB environments, and resulted in the evolution of depigmented skin. As hominins dispersed outside of the tropics, they experienced different intensities and seasonal mixtures of UVA and UVB. Extreme UVA throughout the year and two equinoctial peaks of UVB prevail within the tropics. Under these conditions, the primary selective pressure was to protect folate by maintaining dark pigmentation. Photolysis of folate and its main serum form of 5-methylhydrofolate is caused by UVR and by reactive oxygen species generated by UVA. Competition for folate between the needs for cell division, DNA repair, and melanogenesis is severe under stressful, high-UVR conditions and is exacerbated by dietary insufficiency. Outside of tropical latitudes, UVB levels are generally low and peak only once during the year. The populations exhibiting maximally depigmented skin are those inhabiting environments with the lowest annual and summer peak levels of UVB. Development of facultative pigmentation (tanning) was important to populations settling between roughly 23°and 46°, where levels of UVB varied strongly according to season. Depigmented and tannable skin evolved numerous times in hominin evolution via independent genetic pathways under positive selection.ariation in skin color is the most noticeable of human polymorphisms. As visually dominant mammals, we readily notice differences in skin color in each other. As primates who uniquely use language to create categories, we readily give names to these differences. Since the mid-18th century, skin color has been the single most important physical trait used to define human groups, including variously named varieties, races, subspecies, and species. Charles Darwin observed variation in human skin color while abroad during the voyage of the H.M.S. Beagle (1831-1836), but he soundly rejected the notion that physical differences such as skin color constituted the basis for distinguishing separate human species (1). Darwin's rejection of the existence of distinct human species was based upon his observation that human groups "graduate into each other, and that it is hardly possible to discover clear distinctive character between them" (1, p. 226). His aversion to the separation of humans into discrete species was also motivated by his vehement aversion to slavery, which in his lifetime was defended and promoted on the basis of the superiority and inferiority of allegedly distinct human species (2). It is also well known that early in his career, Darwin collected copious notes on human origins and descent (3), but "without any intention of publishing on the subject, but rather with a det...

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Remarks on the environmental adaptation of man

Cited by 27 publications

References 11 publications

Birth weight, climate at birth and the risk of obesity in adult life

Birth weight, climate at birth and the risk of obesity in adult life

Climatic influences on human body size and proportions: Ecological adaptations and secular trends

Human skin pigmentation as an adaptation to UV radiation

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