quote:Human body size and body proportions are interpreted as markers of ethnicity, ‘race,’ adaptation to temperature, nutritional history and socioeconomic status. Some studies emphasize only one of these indicators and other studies consider combinations of indicators. To better understand the biocultural nature of human size and proportions a new study of the growth of Maya-American youngsters was undertaken in 1999 and 2000. One purpose of this research is to assess changes in body proportion between Maya growing up in the US and Maya growing up in Guatemala. Height and sitting height of 6–12-year-old boys and girls (n=360) were measured and the sitting height ratio [sitting height/height]×100, a measure of proportion, was calculated. These data are compared with a sample of Maya of the same ages living in Guatemala and measured in 1998 (n=1297). Maya-American children are currently 10.24 cm taller, on average, and have a significantly lower sitting height ratio, (i.e. relatively longer legs, averaging 7.02 cm longer) than the Guatemala Maya. Maya-American children have body proportions more like those of white children in the US than like Maya children in Guatemala. Improvements in the environment for growth, in terms of nutrition and health, seem to explain both the trends in greater stature and relatively longer legs for the Maya-Americans. These findings are applied to the problem of modern human origins as assessed from fossil skeletons. It has been proposed that heat adapted, relatively long-legged Homo sapiens from Africa replaced the cold adapted, relatively short-legged Homo neandertalensis of the Levant and Europe [J Hum Evol 32 (1997a) 423]. Skeletal samples of Maya adults from rural Guatemala have body proportions similar to adult Neandertals and to skeletal samples from Europe with evidence of nutritional and disease stress. Just as nutrition and health status explains the differences in the body proportions of living Maya children, these factors, along with adaptation to climate, may also explain much of the differences between the Neandertal and African hominid samples.
Posts: 7085 | From: Fallbrook, CA | Registered: Mar 2004
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This is a very important post. Note the dietary impact on people in such a short period of time.
Orientals in America are also experiencing this change.
-------------------- Across the sea of time, there can only be one of you. Make you the best one you can be. Posts: 4028 | From: NW USA | Registered: May 2005
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@Truthcentric I can't read any of your links to article. I assume they are screen saves that show the headline in a journal, pay to view the rest
you link
Rapid Morphological Change in Living Humans: Implications for Modern Living Humans Bogin 2003
there is also Bogin's related paper from a year earlier. I'm not sure if it's all covered in his later article or not
Rapid change in height and body proportions of Maya American children. Bogin B, Smith P, Orden AB, Varela Silva MI, Loucky J. Am J Hum Biol. 2002
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On Rapid Morphological Change in Living Humans, can somebody post or link the conclusions of the article or the whole thing, thanks
Posts: 42939 | From: , | Registered: Jan 2010
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quote:Human body size and body proportions are interpreted as markers of ethnicity, ‘race,’ adaptation to temperature, nutritional history and socioeconomic status. Some studies emphasize only one of these indicators and other studies consider combinations of indicators. To better understand the biocultural nature of human size and proportions a new study of the growth of Maya-American youngsters was undertaken in 1999 and 2000. One purpose of this research is to assess changes in body proportion between Maya growing up in the US and Maya growing up in Guatemala. Height and sitting height of 6–12-year-old boys and girls (n=360) were measured and the sitting height ratio [sitting height/height]×100, a measure of proportion, was calculated. These data are compared with a sample of Maya of the same ages living in Guatemala and measured in 1998 (n=1297). Maya-American children are currently 10.24 cm taller, on average, and have a significantly lower sitting height ratio, (i.e. relatively longer legs, averaging 7.02 cm longer) than the Guatemala Maya. Maya-American children have body proportions more like those of white children in the US than like Maya children in Guatemala. Improvements in the environment for growth, in terms of nutrition and health, seem to explain both the trends in greater stature and relatively longer legs for the Maya-Americans. These findings are applied to the problem of modern human origins as assessed from fossil skeletons. It has been proposed that heat adapted, relatively long-legged Homo sapiens from Africa replaced the cold adapted, relatively short-legged Homo neandertalensis of the Levant and Europe [J Hum Evol 32 (1997a) 423]. Skeletal samples of Maya adults from rural Guatemala have body proportions similar to adult Neandertals and to skeletal samples from Europe with evidence of nutritional and disease stress. Just as nutrition and health status explains the differences in the body proportions of living Maya children, these factors, along with adaptation to climate, may also explain much of the differences between the Neandertal and African hominid samples.
SO in addition to adapting to the shift to agriculture, the tropicals of the Nile Valley were also adapting to millennia in the monsoon-swept cooler Sahara in its more greenbelt phase, as well as the more temperate sub-tropical climate of Egypt. Both these factors (agriculture and temperature adaptation) can well explain diversity in the Nile Valley without the automatic need to invoke reputed "wandering Middle Easterners" or "Mediterraneans".
Further, data suggests that Nile Valley volk like the Badarians and their precursors were world leaders at one time in food production. They had the whole diet thing down earlier than most.
QUOTE: "With the onset of the Neolithic, the dietary diversity of hunter-gatherers is replaced with dietary specialization on one or a few cereal crops and the products of domestic animals... Increasing sedentism and population density are almost universally associated with increases in infectious disease.. and may underpin the the reduction in stature in the Predynastic period. Archaeological evidence suggests that the Badarian civilization had higher population density than did any other contemporaneous civilizations (Gabriel, 1987, Hassan 1988)." --Pinhasi and Stock 2011. Human Bioarchaelogy of the Transition to Agriculture
“The adoption of this broad adaptive strategy provided the large food supply needed by a growing population, but achieving maximum production called for a good deal of planning and the management of labour. This marks the beginning of an organized food-producing system: agriculture.”
“Dating from more than 15,000 years ago, the evidence from the Nile valley is arguably the earliest comprehensive instance of an organized food-producing system known anywhere on Earth.” --Africa: A Biography of the Continent, by John Reader, 1998, pp. 120-173
Posts: 5905 | From: The Hammer | Registered: Aug 2008
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Yes, having tropically adapted limb proportions doesn't just have implications for limb proportions, but also for the arms and legs as a whole; tropically adapted limbs cause the arms and legs as a whole to be longer than same height individuals with cold adapted limbs.
I agree with them as far as that goes. But how can they say, based on their limited data (no limb proportions), that environmental influences can (partially) explain Palaeolithic differences between the different human species?
Their own data indicates that Maya Americans fall within the range of Europeans; well nurtured Mayans group with well nurtured Europeans, and deprivated Mayans group with deprivated Europeans. Since Europeans have limb proportions that have been stable throughout different studies, it would be reasonable to say that Mayan limb proportions would have remained stable as well, given their European-like range.
Unless I'm missing something, it seems to me this data really doesn't have implications for Paleolithic human species, and that they only added data to the well known fact that people grow taller when they live healthier life styles.
Posts: 8785 | From: Discovery Channel's Mythbusters | Registered: Dec 2009
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