[…]
>>>Thadley: I'm disagreeing that the example you described is actually a
good attempt at testing the hypothesis that life could evolve solely from
what we classify as the building blocks of life.
DNAunion: My main point was, (1) if there truly IS SOMETHING that can
arrange matter in complex and organized ways, and (2) there truly IS NOTHING
that opposes matter's being arranged in organized and complex ways, and (3)
we take ALL of the PREEXISTING & FUNCTIONING components of a bacterium and
release them into an area *immediately surrounding* the lysed bacterium, then
why will the components not again become ordered/arranged as a functioning
bacterium? Nothing new has to be created, just that which existed a
*minute* earlier needs to become reestablished: but it doesn't.
And if we can start with every single physical and operational entity of a
functional cell: every amino acid, nucleotide, polysaccharide, lipid, tRNA,
mRNA, rRNA, DNA, DNA polymerase, DNA ligase, DNA helicase, single-stranded
binding protein, RNA primase, ribosome, the genetic code, transcription,
translation, replication, anabolic and catabolic pathways, etc: and allow
them to become disordered spontaneously simply by making the surrounding
wall/membrane leaky and these still won't self-organize into a functioning
cell, then why is it valid to make the much bigger leap of faith to believe
that pools of *far simpler* and random organic molecules could have become
organized in the complex ways associated with a bacterium, by the same kind
of undirected natural processes that fail here?
Do you disagree with this logic, and if so, how?
>>>DNAunion: Let me point out though that I was discussing a fully-autonomous
bacterium, and not one involved in any form of symbiosis. If one were to
take a single fully-autonomous bacterium - keeping it supplied with the
nutrients, like sugars, it needed to survive all the time - and lysed it, the
"guts" (cytosol, ribosomes, circular DNA, etc.) would leak out : the vital
concentration gradient would be gone, the cellular reactions would cease, and
the cell (and all its components) would be dead (this is in fact one method
employed by bacteria to kill others: they produce an oligopeptide that forms
a leaky pore in the other bacterium). This process is irreversible
(following "times arrow"): the chemical reactions will not self-organize back
into a sustained metabolism capable of supporting life and the bacterium will
not re-assemble from its now disorder "parts". This is true even if one
heats the petri dish, or exposes it to intense UV, or jars it around, or
supplies any other kind of undirected energy.
>>>THadley: It's true, but there isn't necessarily any sort of law that
prevents it from reassembling into a new life form as much as the logic that,
if individual bacteria parts existed seperately at any time, they would have
now evolved to be incapable of "living" on their own.
DNAunion: I don't follow the logical connection there. The point you bring
up seems to me to be irrelevant as to whether or not there is anything that
prevents their components from reassembling.
Why wouldn't the bacterium reassemble into the *same* life form it was before
it was lysed? The arguments presented against me here have been that (1)
there is something that can lead to matter's being arranged in complex and
organized states, and (2) there is nothing that opposes matter's becoming
arranged in complex and organized ways. If these were both true, then why
can't the former bacterial cell regain its original complexity, organization,
and complication? Whether the broken down components can live by themselves
does not address the main point.
>>>Thadley: Recall Margulis' Symbiotic Theory for the origin of eukaryotes
as an example of a larger organism forming from smaller, "live" parts.
DNAunion: Yes. The "fusing" of two preexisting, functioning cells which
were both already complex and organized arrangements of matter.
>>>Thadley: […] So, under this hypothesis, the right way to break down a
eukaryote into its original parts would be to break it into a prokaryote and
assorted aerobic bacteria.
DNAunion: I was not discussing eukaryotes. But I know how you were misled:
I inadvertently mentioned *mitochondria* as being one of the components of
the cells I was discussing, which I should not have done as I was addressing
bacteria.
I am not sure how the "it was originally two separate, functioning, living
entities that combined and then became co-dependent so each lost its
autonomy" argument holds up in relation to bacteria.
>>>Thadley: Of course we can't do that and actually have two living
organisms because of the result of evolution over time on symbiotic
relationships. Thus, the idea that we can break down living organisms and
disprove anything by not seeing their parts reassemble has a problem.
DNAunion: I disagree: remember, I am discussing bacteria.
Conceptually, if a functioning bacterium is composed of ABC (say DNA,
enzymes, and ribosomes) and we break it down into the individual components
A, B, and C, and there is something that can arrange matter in complex and
organized ways, and matter has nothing against being arranged in complex and
organized ways, then why won't the individual parts A, B, and C reform ABC, a
functioning bacterium?
That the individual constituents are not themselves living is not the issue:
if all the components that formed a functioning, living cell are still
present (yada yada yada), then the individual components should be able to
reform the same *or* another kind of functioning cell. But they can't.
>>>Thadley: However, it would be true that if we could supply the mechanisms
and structures that evolution likely has erased, we could break a eukaryote
cell into two simpler, living organisms that could, subsequently, reform
given the right environment (assuming the hypothesis is correct).
DNAunion: If you could separate an "aggregate" living cell into two
autonomous living cells, then reunite them forming again the original
"aggregate" cell, what would that demonstrate? It still would not
demonstrate in the least that matter can become arranged in the complex and
organized ways associated with life by purely-natural means because the
components themselves were already arranged in comlex and organized ways
associated with life.
>>>THadley: And if symbiosis played other roles, we might also expect the
same reasoning to apply to many of the individual "building blocks" of life.
DNAunion: Do you have an example or can you expand on this?
This archive was generated by hypermail 2b29 : Sun Oct 29 2000 - 18:51:14 EST