Re: colour vision

From: firstjois (firstjoisyike_at_hotmail.com)
Date: 07/21/04 

Date: Wed, 21 Jul 2004 09:01:28 -0400

Dave Eadsforth wrote:
[snip]
>>
>> Some years ago, a TV programme pondered the fact that that colour
>> vision deficiencies in men, to have persisted to the present time
>> rather than having been bred out, must have had conferred some
>> advantage in pre- historic times. It occurred to me that the answer
>> was that deficiencies in colour vision, especially to humans living
>> in a tribe where other people had perfect vision, conferred no
>> advantage, and simply did not impact their existence enough to stop
>> them breeding.

Agreed. There was an article about discovering a blind dog in a hunting
pack only when it ran into a bush that cut its face - it didn't duck when
the others did. Apparently healthy and capable of running with the pack
and behaving normally until this accident but finally determined to have
been blind from birth.

>>
>> On the same basis, I incline to think that a lower rate of colour
>> blindness in women may simply be a fortunate feature of their make-up
>> and of marginal advantage in day to day existence.

Couldn't this just be due to the location of the defect on the gene men
only get one copy of - and nothing more elaborate than that?

>> Men tend towards
>> baldness, women do not; what are the respective evolutionary
>> advantages?

Well, maybe all the men who tended towards baldness at 16-23 years of age
have already been tossed out of the gene pool. Getting bald at 45 years
of age wouldn't be a big deal if the average age of death was 45. Same for
ear hair. Certainly the same for nose hair.

Jois

[snip]

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