[ExI] Armchair Evolutionary Psychology: Larks vs Night Owls

[Emlyn]

On 15/03/2008, Kaj Sotala <xuenay at gmail.com> wrote:
> On 3/15/08, Kaj Sotala <xuenay at gmail.com> wrote:
> > On 3/15/08, Emlyn <emlynoregan at gmail.com> wrote:
> >  > I agree, regarding not everything having an evolutionary explanation.
> >  >  In this case though, there are genes explicitly controlling the
> >  >  behaviour, which does want such an explanation.
> >
> > Genetic drift?

Well, this linking between sleep cycles and personality type, seems to
specific for drift. Sleep cycles might drift under no pressure, and
personality type similarly, but both together?

>
> Also - eye color, hair color, and blood type are explictly controlled
> by genes. With the possible exception of blood type (not entirely sure
> about that one), I don't think differences in any of them have any
> particular evolutionary reason.
>

Possibilities for eye & hair color:
- unique sexual selection pressures in northern europe:
http://www.ehbonline.org/article/S1090-5138(05)00059-0/abstract
- An interesting discussion here, refuting some ideas:
http://evoandproud.blogspot.com/2007/10/why-are-europeans-whiter-than-north.html
- And some more stuff, detail is interesting:
http://neurologicalcorrelates.com/wordpress/2007/10/28/pigment-last-time-i-promise/

The conclusion I draw from this probably terribly unrepresentative
sample of stuff I scratched up via google, is that the massive eye and
hair color variations in north and eastern europeans must have been
positively selected for (moves too decisively, and doesn't happen in
other candidate populations, eg: inuit), so it's a positive pressure,
not drift (which is a lack of pressure), but we don't really know what
that pressure was. Also it's useful to note that it's an aberation
overall, african type skin, eyes, hair is the ancestral norm.

Blood Types also seem to be a poorly understood phenomenon, but here's
some discussion:
http://www.madsci.org/posts/archives/2003-10/1067015749.Ge.r.html

-- 
Emlyn

http://emlynoregan.com