In a message dated 2/21/2001 5:02:34 AM Alaskan Standard Time,
[EMAIL PROTECTED] writes:
> Actually, a major paradigm shift *has* been occurring in taxonomy over the
> past 15 years, based on the accumulated data generated by the molecular
> biology-genomics revolution. We now have three Domains of life - a higher
> taxonomic order than "kingdom." These domains are Bacteria, Archaea, and
> Eukarya, the primary branches of our phylogenetic tree. The taxonomists of
> the 18th and 19th centuries of course had no way of knowing that they were
> classifying organisms in only one of the three domains of life. Even
> researchers in the first three-quarters of the 20th century had to rely on
> morphology and physiology to try to make sense of the microbial world. DNA
> doesn't lie, however; once sequencing became inexpensive and rapid, the
data
> began to accumulate and people like Karl Woese (a likely future Nobel
> laureate) began to see a very different phylogenetic tree taking shape.
Now
> we're even wondering if a "tree" with branches is even the best way to look
> at it. These are fascinating days...
>
Thanks for the pointers, Dr. Zeigler. I was aware of the 'Archaea'
revolution, and new modes of thinking re phlogeny, but didn't know that
they'd be reorganized into Domains (I suppose in 18th century terms, they'd
be called Empires?).
However, I was referring more to misnomers in existing phylogeny, although
DNA discoveries may be a way to address those misnomers.
One of my hobbies is paleontology, yet I'm struck by the various labels for
hominids... its a real mess. From ramapithecus on forward, there are no
clear guidelines, save one: there is a conscious or unconscious effort to
separate humans from chimps as much as possible, even though the DNA itself
does not suggest this. Frankly, I suspect that humans and bonobos could be
crossbred, although the offspring would likely be sterile.
Of course, besides causing a huge religious backlash, moral backlash, etc,
etc, such a crossbreed would clearly toss out all distinctions of
australopithecine versus hominid versus proto-human versus human. For that
matter, if you have to keep the 'homo' genus label, then by sheer terms of
years, we're all varients of homo erectus, not really a form of homo sapiens.
Back to Europa and all things Europan: imagine the mess in phylogeny, if /
when a non-terrestial life form is discovered... would it be another domain,
or another 'tree' entirely? And, what if a martian microbe could somehow
exchange genes with a terrestial microbe?
Clearly, someone is going to suggest that this has already happened, that we
are all the descendents of martian microbes, etc. However, a Europan
microbe, if discovered, would presumeably have no relation whatsoever... and
the plot thickens, along with the primordial soup.
-- John Harlow Byrne
==
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