[extropy-chat] why the vertebrate eye might not be suboptimal after all

The Avantguardian avantguardian2020 at yahoo.com
Sat Jul 8 00:59:10 UTC 2006



--- Damien Broderick <thespike at satx.rr.com> wrote:

> Drat, nobody seems to take my point. It's got
> nothing to do with 
> *intelligent* design, only with locally and
> sequentially optimized 
> design. If you find scads of cases of similar
> designs that work well 
> enough until offspring have offsprung, maybe some of
> the apparent 
> deficits have unsuspected advantages--as with
> antagonistic pleitropy. 
> (But I agree that the trouble with a racheting
> selection system is 
> that often you can't get there from here *purely by
> darwinnowed 
> mutation*, so critters perforce make the best of it.
> Hence, my 
> friend's astute comparison with the Hubble's
> optics.)

No I actually got your point, Damien. I just wanted to
indulge in some ID bashing.

What Ayoub is arguing is that vertebrate eyes have
achieved a local maximum. Most evolved structures are
in a local maximum relative to a given set of
constraints. To illustrate, lets say you are on top of
the shortest mountain in a mountain range. You look
around and there are plenty of mountains taller than
the one you are on but no matter what direction you
start walking you will be going down hill. Thus you
have to go pretty far down before you can climb back
up to a spot higher than where you started. Natural
selection is like walking a mountain range on foot.

I don't necessarily agree with Ayoub because there are
a huge variety of vertebrate eyes out there. Which
vertebrate has the best eyes? It depends entirely on
what niche you are optimizing vision for. A naked mole
rat lives in complete darkness and gets around by
touch, hearing, and smell so it doesn't need eyes at
all. A falcon who is routinely flying in excess of 90
mph would need exceptionally acute vision, especially
since it needs to intercept very agile flying prey. 

Thus in regards to ANY evolutionary trait, the fittest
is entirely relative to a given set of environmental
contraints. That is the major intellectual shortcoming
of eugenics. In a rapidly changing heterogenous
environment, the best is only the best until the
weather changes.


Stuart LaForge
alt email: stuart"AT"ucla.edu

"God doesn't play dice with the universe." - Albert Einstein

"Einstein, don't tell God what to do." - Neils Bohr

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