Text 626, 95 rader
Skriven 2004-11-03 05:57:00 av Tinyurl.Com/uh3t (1:278/230)
Ärende: Re: First Mutation Was Bi
=================================


> From: tomhendricks474@cs.com (TomHendricks474)
> Are you saying a replicator pops up and it has a built in metabolism
> system that utilizes hydrogen sulfide?

I'm not saying hydrogen sulfide specifically. It could be any one or
more of several non-neutral (oxidizing or reducing) chemicals that are
produced in abundance by geothermal vents or by UV radiation or by
ultra-hot exposure from crashed comets/meteors or by lightening etc.
Also it might not be the immediate chemical, but rather some derived
chemical of lower energy, that is directly used by the replicator.

In any case, the answer to your question depends on your definition of
the word "metabolism". The most basic quality of any sort of metabolism
is a chemical reaction whereby chemicals of different redox potential
are reacted against each other and the resultant negentropy is used in
some useful way as compared to just wasting it as low-level heat, or a
single meta-stable chemical is conducted to decay while collecting the
energy of decay likewise to use in some useful way. (There may be
additional kinds of chemical reactions likely in the pre-biotic world
that likewise can yield useful energy. If so, include them as
possibilities here.) But the word "useful" implies some specific agent
benefiting from the reaction. So let me first define "pre-metabolism"
to be any redox etc. etc. reaction that simply produces some
"interesting" chemical, for example a chemical with more parts than its
precursors. So in the pre-biotic oceans, I speculate that a lot of
Miller-Urey types of chemistry was going on, where pre-metabolism as I
define the term was producing lots of complicated chemicals such as
amino acids.

Now as soon as a catalytic cycle forms where some chemical catalyzes
the making of itself (indirectly via the cycle of other catalysts in
the loop) faster than it gets destroyed, this one chemical
exponentially grows in quantity, past the threshold where chance
destruction could make it go extinct. Nothing much is new in the
pre-metabolism that has been going on and is still going on, but
because we're now talking about this one specific replicator, what was
previously pre-metabolism can now be re-named "metabolism" because it
specifically benefits this one replicator.

It doesn't matter whether you allow the word "metabolism" to apply to
this kind of chemistry or not. I never said metabolism was necessary
for replication. I merely said the catalytic cycle would exponentially
grow in quantity until it dominated the chemistry of the ocean. It'll
still do that, regardless of whether you consider that kind of
chemistry to be "metabolism" or not.

So if you allow that usage of the word, then the answer to your
question is that pre-metabolism becomes metabolism as soon as there's a
specific replicator taking great advantage of it. If you don't allow
that usage, then the answer to your question is that the replicator
doesn't need anything you'd call "metabolism" to exponentially grow in
quantity.

However because of the way you suddenly threw in the phrase "built in
metabolism system", I suspect you are trying to use the debate trick of
switching definitions: You get everyone to agree that some sort of
metabolism (my definition above) is needed for the replicator to
replicate, but then you switch to the more advanced biologicaal
definition of a metabolic system, tricking us into accepting that
*that* is needed (which it isn't), and then claiming such a system
could not have come into existance so early in the process of
abiogenesis. If that was your idea, please don't try that again.

The neat thing about the Miller-Urey experiment is that it showed us
two things: (1) A rather wide variety of complex organic chemicals are
produced, somehow, just from simple chemicals and some source of
ionizing radiation. (2) Significant yield of several complex chemical
species, such as some amino acids, were produced. The latter shows that
in the pre-biotic world there may have been a large foodstock not just
of simple chemicals such as hydrogen sulfide but of some complex
chemical species, and the former suggests that among the wide variety
of chemical species there should be various catalysts appearing from
time to time.

> That's hard to imagine - and with it having no defenses - it hasn't
> had time to adapt to anything - it'll somehow survive this environment?

By making more copies of itself faster than copies get destroyed.
Why didn't you already know that? Why did you have to ask?

Ants have no defense against people accidently stepping on them.
Yet they survive quite nicely by producing more of themselves faster
than they get stepped on. Most species of life in fact survive not by
protecting themselve from terrible hazards but merely by breeding fast
enough to replace the lost individuals. The same would apply to the
first chemical replicator.
---
ū RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info@bbsworld.com

---
 * RIMEGate(tm)V10.2á˙* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 11/3/04 5:57:44 AM
 * Origin: MoonDog BBS, Brooklyn,NY, 718 692-2498, 1:278/230 (1:278/230)