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Re: Europa Dope

On Mon, 04 Jul 2005 09:15:27 -0300 Roberto Takata <rmtakata@gmail.com>

> > Yes, I do have a question for the list:  What is the current opinion
> > the monophyly of all Earth life?

> It's well established on the basis of the
> "universal" genetic code shared virtually
> by all [Earth] life forms - the exceptions are, as far as we
> can infer, theme variations. The genetic
> sequences similarity and differences
> pattern support this view too.

Ahhh, but in order to make such a claim, you *must* assume that there is
more than one possible biochemical pathway for carbon-based life to form.
 But what if there is *only* one possible way for life to form?  How,
then, could a geneticist distinguish polyphyletic Earth life from
monophyletic Earth life?  This is a valid hypothesis, because it has the
potential to be falsified.

The only way to test this hypothesis is to find microbes on Mars or
Europa (or some other planet).  If the microbes' genetic code contains
some "exotic" biomolecules that are not found in Earth life, or if the
genetic code's ultrastructure is different than a double helix, then that
proves that that there is more than one biochemical pathway for life to
develop (aka, "true" polyphyletic life), and the hypothesis (above) would
be falsified.  But if the genome of the alien microbes  resembles the
genome of Earth microbes, then nothing was proven or falsifed.

> But is that thread on topic in this list?

We'll see in short order, I'm sure.  ;-)