Re: An alternative to ST and AAT
John Waters (jdwaters@dircon.co.uk)
24 Nov 1996 21:02:48 GMT
Gerrit Hanenburg <G.Hanenburg@inter.nl.net> wrote in
article <57448t$i6h@news.NL.net>...
> The regression equation for primates that relates female
bodyweight to
> age at first breeding for females,
>
> log (age at first breeding)=log (43.5)+0.44*log (female
bodyweight)
> (age first breeding in days,bodyweight in grams) r=0.92
>
> generates an age at first breeding for A.afarensis of
11.0 years.
JW: Is it possible to do the same sort of analysis on H.
habilis and H. erectus? My interest here is concerned with
the LBI broods. If these species exhibited increased
alfricial development, I would expect a proportional
increase in the adult stages of development. This would
imply a later age at first breeding.
>
> What's even more interesting is that the age at death of
several
> juvenile hominids has been assessed on the basis of
incremental growth
> lines (striae of Retzius,a kind of dental equivalent of
tree rings) in
> their teeth. For Australopithecines this age was
3.15-3.48 years
> (Bromage & Dean 1985). Some of these individuals died
near the time of
> eruption of the lower permanent M1 (SK 63,STS 24 and
LH2)(Smith 1991).
> Chimpanzees are known to erupt their lower permanent M1
at the age of
> ~3 years,while modern humans erupt theirs at ~6 years
(Smith et al.
> 1994). This is also a strong indication that early
hominids had an
> ape-like developmental pattern.
JW: Likewise, it would be interesting to know whether H.
habilis and H. erectus infants were maturing later also. I
wouldn't expect a very marked difference. Although the
brain nearly doubled in size, I think there were changes in
the pelvis as far as H. erectus was concerned, so the
degree of alricial extension may not have been
proportional.
John.
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