pearl wrote:
> "ant and dec" > wrote in message ...
>> pearl wrote:
> <..>
>> Thanks for that. Very interesting; of particular personal interest was
>> the anthropological articles on calcium and osteoporosis.
>
> You're welcome.
>
>> :-)
>>
>>
>>
>> The theory I was thinking of was the "brain food theory":
>>
>>
>> Brain food
>>
>> Because meat is rich in calories and nutrients, easy-to-digest food,
>> early Homo lost the need for big intestines like apes and earlier
>> hominids had. This freed up energy for use by other organs. This surplus
>> of energy seems to have been diverted to one organ in particular - the
>> brain. But scavenging meat from under the noses of big cats is a risky
>> business, so good scavengers needed to be smart. At this stage in our
>> evolution, a big brain was associated with greater intellect. Big brains
>> require lots of energy to operate: the human brain uses 20% of the
>> body's total energy production. But the massive calorific hit provided
>> by meat kick-started an increase in the brain size of early humans.
>>
>> http://www.bbc.co.uk/sn/prehistoric_...thought1.shtml
>
> If that were the case, carnivores should have massive brains!
>
>> Mind you, this was written by Robert Winston who's has sold himself to
>> the food industry.
>>
>> http://politics.guardian.co.uk/lords...560223,00.html
>> http://www.omega3.co.uk/omega3/pages/omega_3.php
>
>
>
> Proc Biol Sci. 1998 Oct 22;265(1409):1933-7.
> Visual specialization and brain evolution in primates.
> Barton RA.
> Department of Anthropology, University of Durham, UK.
>
> Several theories have been proposed to explain the evolution of
> species differences in brain size, but no consensus has emerged.
> One unresolved question is whether brain size differences are a
> result of neural specializations or of biological constraints
> affecting the whole brain. Here I show that, among primates,
> brain size variation is associated with visual specialization.
> Primates with large brains for their body size have relatively
> expanded visual brain areas, including the primary visual cortex
> and lateral geniculate nucleus. Within the visual system, it is, in
> particular, one functionally specialized pathway upon which
> selection has acted: evolutionary changes in the number of
> neurons in parvocellular, but not magnocellular, layers of the
> lateral geniculate nucleus are correlated with changes in both
> brain size and ecological variables (diet and social group size).
> Given the known functions of the parvocellular pathway, these
> results suggest that the relatively large brains of frugivorous
> species are products of selection on the ability to perceive
> and select fruits using specific visual cues such as colour.
> The separate correlation between group size and visual brain
> evolution, on the other hand, may indicate the visual basis of
> social information processing in the primate brain.
>
> PMID: 9821360 [PubMed - indexed for MEDLINE]
> http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

Thanks again.

I have moved my position on whether meat had a major part to play in
human evolution. I will read more, but on balance there seems little
evidence to support that it did.


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