[TML] Alien ecologies

[Bruce Johnson]

On Aug 29, 2008, at 1:59 PM, Greg Kettler wrote:

>> That's because the absorbtion peak does not depend on the protein
>> (which can change via evolution) but the captive metal atoms  
>> chemistry
>> (which cannot)
>
> The peak can and does change. Chlorophyll b has a different peak, but
> the same metal ion.


Sorry for that, clicked send by accident.

You're correct, my biochem is woefully rusty, but in the main the  
absorption spectrum (and the width of the absorption peak) is still  
largely defined by the metal ion, which has a fairly narrow  
range...you'll note that the difference between Chlorophyll a and b is  
only 20 nm.

However, something important getting lost in this discussion is that  
evolution does not produce the optimal solutions for facing  
organisms...if it did our knees would work a hell of a lot better :-)

It produces solutions to problem by minor modifications of existing  
'kit', the molecular toolbox that an organism's dna codes for.

They've used this very principle to trace the evolution of bacterial  
flagella from ion channel proteins in cell membranes....one of the  
things that the ID folks point to as 'irreducible complexity', but  
really aren't.

-- 
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs