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Re: puzzle of the negrito: isolated archaic populations
Dan Barnes (dbarnes@liv.ac.uk)
Thu, 12 Dec 1996 18:20:49 GMT
In article <584qot$p0j@news.sdd.hp.com>, geroldf@sdd.hp.com says...
>
>Remnant populations of small, frizzy-haired, forest-dwelling peoples
>still exist (or did within the last century) in isolated pockets
>throughout asia, from the phillipines, malaysia, indonesia, the
>andaman islands, and possibly india as well. Average height for men
>ranged from around 4 1/2 feet to just under 5, leading to the name
>"negrito", and begging the question of relations to the african
>pygmies. How did the negritos come to be? The answer to this question
>could have important implications for the history of human evolution.
>
If Ruff (1994) is correct then a reduction in stature is a response to adaptations
to rain forest conditions (and I'm sure sexual selection comes into it as well). He
examined the width of fossil Apiths and H.e. (admittedly a very small sample as
pelvises, which he used, are rare) and showed that they fit into a general
climatic distribution of moderns. Since, in the generalisation of the human body
(a cylinder), there is no change in surface area to volume ratios with increasing
height he came to the conclusion that the difference in height correlated to the
greater volume need for water storage that a savannah dwelling hominid would
need. From these results it is not suprising that a people who have spent a long
time living exclusively in rain forests would develop a decrease in height. It
would seem that if Ruff's analysis is valid that it is an example of parallel
evolution - with two groups of people adapting to similar environmental
conditions.
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