> 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.
>>Thadley: It appears to be a "law" of nature that the individual parts of
an organism will also lose any extra mechanisms or functionality that would
allow them to exist independently; they will become dependent on other parts
for essential ingredients for basic functionality.
DNAunion: By saying this, are you suggesting that the individual components
of a bacterium used to be capable of living independently, but once
incorporated into bacteria, they lost that ability? For example, were
ribosomes once free-living entities, and at that ancient time,
“bacteria” did not have ribosomes (but later acquired them
through symbiosis)?
>>>Thadley: Thus, breaking a bacterium down into individual components would
accomplish the same result as breaking a bacterium down into individual
molecules, or individual atoms. Nothing in the short term.
DNAunion: Or in the long term.
“Oparin suggested that collections of molecules were continually coming
together in the prebiotic soup, and that the ones that persisted the longest
would come to predominate. Somehow, this chemical evolution led to the first
self-replicating entities, or protobionts, and once this had happened,
biological evolution took over. This is the scenario presented in textbook
accounts of the origin of life, and this mind-set had dominated thinking in
the field. But there are too many gaping holes in this story for us.
Protobionts arose somehow from the collection of organic molecules in the
Earth’s early primordial oceans. BUT WE KNOW THAT EVEN IF ONE WERE TO
RECREATE IN A LABORATORY FLASK A RICH AND COMPLEX APPROXIMATION OF AN EARLY
EARTH SOUP, STERILIZE IT, AND THEN LET THE FLASK SIT ON A SHELF, IT WOULD SIT
THERE *INDEFINITELY* WITHOUT ANY SIGN OF LIFE – OR INDEED ANY SIGN OF
OPARIN’S CHEMICAL EVOLUTION.” (emphasis added, Christopher Wills
& Jeffrey Bada, The Spark of Life: Da
rwin and the Primeval Soup, Perseus Publishing, 2000, p XV)
Of course, the authors don’t leave it there: they continue,
“There has to have been a powerful mechanism behind the appearance of
the first protobionts.” and offer Darwinian evolution as that powerful
mechanism.
But the important point here is that the matter sitting in that flask –
the same types of matter that *theoretically* formed a protobiont –
will *NEVER* "self-organize" into either a full-blown cell or a
“mere” self-replicating entity.
>>>Thadley: However, theories of symbiosis would propose that the basic raw
materials of modern life were originally incorporated into seperate, simpler
forms that at various points over time entered into a profitable
relationships other simple life forms to form more successful and more
complex life forms. What appears to be critical to the rapid formation of
complex life is the aggregation of simpler but self-sustainable life -- not
raw materials.
DNAunion: Symbiosis is a method by which *preexisting* life becomes more
complex. I would still like for you to *clearly* state how you are proposing
symbiosis assisted the origin of the very first cells.
>>>Thadley: This, as a logical possibility at minimum, is a mechanism that
is consistent with both 3 and 1 being true. However, I might be
misunderstanding you in general by reading (2) in a different sense then you
intend. Can it be read to say that nothing prevents complexity, but some
mechanisms result in complexity faster than others?
DNAunion: Points 1 & 2 taken together – “(1) … 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” – indicate that all natural reactions would lead
irreversibly toward greater complexity and organization.
One could visualize a ratchet, where changes can occur in only one direction.
Once a change is clicked in the positive direction, that advance is locked
in place and can never be undone: there can be absolutely no regress, only
continual progress. Unless all reactions cease totally, this will eventually
lead the “spilled out guts” of a bacterium "reassembling" into a
bacterium. But since this “self-organization” will not occur,
statements 1 and 2 cannot both be totally accurate.
>>>DNAunion: 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?
>>>Thadley: In this [prebiotic] case, the pools would result in far simpler
"life" than bacteria, and possibly, over time many different kinds of simple
"life" as molded by environmental pressures. This simpler life, then, would
make those "macro"-leaps of complexity with something similar to symbiosis.
DNAunion: What type of simpler life are you referring to? There is no
simpler autonomous cellular life than the “simplest” autonomous
bacterium. As far as the simpler-than-bacteria self-replicators, they are
still only designed – none have been shown to arise under prebiotically
plausible conditions (and many leaders in OOL research express grave doubts
that ever will - at least RNA replicases). And even if a self-replicator
arose, how would symbiosis of preexisting simple life forms explain the use
of ribosomes by all cells, since ribosomes are neither free-living nor living
at all, and no material I have read proposes that they ever were?
>>>DNAunion: […] 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: In the case of bacteria, I'm sure it's speculation. However, it
seems that if the concept worked so well for eukaryotes, why not for the
prokaryotes as well?
DNAunion: What would the hypothetical free-living entities be that joined
together to form the first prokaryote? In eukaryotes, the chloroplasts and
mitochondria were formerly free-living bacteria, but prokaryotes don’t
have them. (In addition, Margulis has proposed many other hypothetical
instances of symbiosis – but I am not familiar with them. Are they not
other membrane-enclosed organelles, such as lysosomes, that would be unique
to eukaryotes?).
> 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 the complex and organized ways associated
with life.
>>>Thadley: But the components are simpler than the resulting organisms.
Thus, theoretically, those components could also be decomposed into simpler
components yet, and so on.
DNAunion: But what supports this assumption? What individual free-living
entities could a cyanobacteria (from which mitochondria supposedly evolved)
be broken down into?
> >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?
>>>Thadley: No hard data that I'm aware of, but I think there's a certain
elegance to the theory. This is something like Margulis' Gaia hypothesis.
DNAunion: A little off the subject, but somewhat related. Margulis has
stated to the effect (and I agree) that it is a bigger leap going from
“amino acids” to a bacterium than it is going from a bacterium to
a human: that is, prebiotic chemical evolution is more difficult than
subsequent biological evolution (the real quote can be found at
www.pansermia.org, but I don’t know exactly where at that site it is).
If the smaller, easier leap (for the first cells to evolve into humans) took
about 4 billion years, then wouldn’t the larger, harder leap (for
prebiotic chemical evolution to produce the first cells) take much longer
than 4 billion years? Yet the maximum windows now being discussed are on the
order of 200 million years, with the average hovering around 50 million, with
some even less.
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