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From: Ellington@Frodo.MGH.Harvard.EDU (Deaddog)
Newsgroups: sci.bio,sci.chem
Subject: Re: "Primitive" != Unevolved (was Re: Forgotten Entities...)
Message-ID: <4618@husc6.harvard.edu>
Date: 7 Nov 90 14:53:41 GMT
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Organization: Molecular Biology, Mass. General Hospital
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References:<4578@husc6.harvard.edu> <90307.154236JAHAYES@MIAMIU.BITNET>

Well said!
However, I think that the previous responses by Drs. Chiaraviglio and 
Yanega (like chemical companies, I find it simplest to assume everyone is 
a Dr.; no disrespect intended) were more subtle than "thermophilic 
archaebacteria stopped evolving."  I believe the central issues are 
(1) Has one deeply-branched lineage of archaebacteria evolved MORE SLOWLY 
(i.e., adopted fewer metabolic or physiological changes over the course of 
time) than other organisms?  (Obliquely, this applies to the bees as well; 
that is, can a lineage evolve slowly relative to other lineages.)
(2) If so, does this imply that the ancient forebear to these organisms 
has characteristics similar to the modern versions?  (I don't believe that 
(2) necessarily follows from (1), since both questions involve the rather 
complex question of what constitutes a 'trait' and whether all 'traits' 
are equal.)
Nevertheless, I could not have summarized the argument against "frozen 
evolution" better than you did.  I am currently struggling with the 
age-old (ha, ha) question of "mode/tempo of evolution" and whether 
thermophily is truly a 'trait.'  If I produce anything remotely coherent, 
I will babble forth.     

Dept. Mol. Biol.
Mass. General Hospital
Non-woof