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Only if you assume a generation is keyed on the "first" birth; it is matrilineal; that culturally child-birthing begins as soon as puberty kicks in (rather than
by sageikosa 14y ago
Only if you assume a generation is keyed on the "first" birth; it is matrilineal; that culturally child-birthing begins as soon as puberty kicks in (rather than being forestalled by social taboos or customs); and that puberty kicks in at roughly the same age then as now, even in an area of scarce resources.
I might think, off the bat, that 30 years is too high as well, but I also might assume they picked that number for a reason. Certainly, I'd like to know what it is as well, as that number is one of two key variables that creates the time-span value used for dating.
- dmm 14y ago> that puberty kicks in at roughly the same age then as now, The age of sexual maturity in women has been decreasing for a while. It seems to be related to a number of things including body mass. So it was probably later for these people. I don't know anything about 30yr generations. http://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_average_age http://en.wikipedia.org/wiki/Menarche#Changes_in_time_of_ave...
- cabalamat 14y ago> The age of sexual maturity in women has been decreasing for a while. That's irrelevant; we're measuring generations of y-chromosomes which are passed by the father; the age of the mother has nothing to do with it.
- sageikosa 14y agoMaybe not directly, but if in general women are paired with men older than themselves, then the age for men might skew upwards also.
- cabalamat 14y ago> ...it is matrilineal... Bear in mind they are counting mutations on the y-chromosome, which is based from father to son. Over a wide range of cultures men on average mate with women who are younder than them, so the time between generations by patrilineal descent will be greater than the time by matrilineal descent.
- bencollier49 14y agoAhhh, that makes a lot more sense. Thanks.