Re: Regularities in brain evolution?

Barry Mennen (
23 Aug 1995 20:24:52 GMT


>In article <41e6lb$>
> (KathieDon) writes:
>> Hello. I'm an "amateur" paleoanthropologist with an interest in
>>evolution, esp. human brain evolution. In Science (16 June 1995),
>>and Darlington propose a model of brain growth across mammals. They
>>suggest that the size of any one brain feature correlates more
>>with overall brain size than with any other feature of the organism.

<major snip>

>>divergence of Homo sapiens from Homo erectus.
>> I'd appreciate any comments on this approach to thinking about
>>evolution. For personal replies, please send messages to:
>> Thanks,
>> Carl
>Coupled with an increase in brain size and head size must have been an
>accomodating change in the pelvic arrangement in order to give birth
>to a larger-headed offspring. While there is a great deal of postnatal
>growth of the head and brain, a significant change in size would
>the pelvis to be able to permit passage. There is some concern in the
>medical community now that the rampant use of caesarian surgery for
>birth is creating a selective pressure for smaller (inadequite)
>birth canals.
>Tim Shickley (

Why would women with size-inadequate birth canals be selected for?
Even docs who are aggressive about doing C-sections have rates of about
25%--also, managed care is now (in USA) putting more pressure on
ob-gyns to do less C-sections.