RNA World...
Dr. Adequate referred to an RNA world as hypothetical; it is just that. The postulation of an RNA World reminds me somewhat of Dean Kenyon's co-authoring of
Biochemical Predestination (with Gary Steinman). This was a postulation that certain amino acids had an attraction to other particular amino acids. And these attractions were such that when the amino acids connected to one another, they were automatically sequenced in the correct way so that proteins were formed (it must be noted that amino acids must be sequenced
precisely the right way in order to form a protein). So this hypothesis would make possible (and really, unavoidable) the formation of complex proteins in a primeval pond. At the time, it appeared as though this
could happen, but there was absolutely no evidence that it
did happen. Dean Kenyon went on to reject his own hypothesis, and become a prominent YEC and an ID proponent.
This anecdote demonstrates the difference between
postulation and
empirically-based claims. One may postulate that there is a
remote possibility of something occurring, or they may make claims backed by evidence. There is indeed a difference. The way that both "biochemical predestination" and an "RNA world" come across to me is as a person saying that they "know" that something (evolution perhaps) is true, and then they formulate every hypothesis necessary to describe parts of the world that the original theory fails to explain. But the only evidence that backs these hypotheses is the "fact" that evolution (yes, this is somewhat generalized) occurred. But this is obviously not good evidence.
Dr. Adequate mentioned that "a lot of the most basic nuts and bolts of the process of making proteins consist of RNA enzymes such as tRNA and rRNA". This is indeed true, but it does not support the notion that RNA, in and of itself, can carry out
all of the necessary functions for life, including reproduction. It has indeed been shown that certain types of RNA have the ability to act as enzymes; but in cells nowadays, we never have RNA that acts completely independently of DNA. Typically, mRNA gets information for amino acid sequencing (this is slightly generalized) from the DNA, and then tRNA and rRNA may act as catalyzers [sic] for the process of protein synthesis. To summarize, we do not see
in vivo any evidence of an "RNA world". But some people have been able to make RNA perform numerous functions
under perfect conditions. This is analogous (credit for this analogy is given to Hubert Yockey) to building a roof for a house, in order that the walls and then finally the foundation can be built without worry of being rained on - because after all, there is a roof to cover you...In like manner, a biochemist can construct the perfect conditions for RNA, and then hypothesize the formation of all the parts we see
in vivo.
And here are a few generalized postulates necessary to an RNA world, postulates which the hypothesis does not prove (of course), borrowed from (who else?) Dean Kenyon:
1. - There was a prebiotic pool of beta-D-ribonucleotides.
2. - Beta-D ribonucleotides spontaneously form polymers linked together by 3', 5'-phosphodiester linkages
3. - A polyribonucleotide (i.e. RNA molecule), once formed, would have the catalytic activity to replicate itself, and a population of such self-replicating molecules could arise.
4. - Self-replicating RNA molecules would have all of the catalytic activities necessary to sustain a ribo-organism.
Bluejay mentioned viruses that contain RNA as a storage of information. But this provides no evidence of the hypothetical RNA world, because the RNA in a virus absolutely cannot be used in and of itself to produce anything: viruses are, by definition, not life, because in order to reproduce, they must use the DNA of culprit cells. Note that we still do not have a case of RNA performing any sort of reproduction independent of DNA: an RNA world is purely
in vitro, not
in vivo. Not to mention the fact that we know relatively little about RNA
in vitro.
If there is one term I hate, it is the term "science" used in reference to historical hypotheses. Science is the investigation of the world through data gathered, experimentation, etc., while historical "science" (ugh) really amounts to nothing less than randomly conjectured hypotheses that have no basis in the world we see around us. We don't see evolution in the world around us (talking about the present). Rather, if evidence is brought, the evidence is confined exclusively to the possibility that evolution
could provide a plausible, naturalistic explanation for the world around us. I would actually disagree with even this, but besides the fact that evolution - in and of itself - is incredibly controversial, you still must deal with the problem that evolution deals primarily with
possibilities, possibilities that involve such postulates as as the existence of a biologically-suited, primeval pond, rich with just the right chemicals (for some of which there is no plausible explanation as to how they could have condensed so close to the sun) to produce amino acids, which are formed by being struck by lightning (another hypothesis), which then interact with ribozymes to be formed into chains of amino acids, which then (through a complex process) form small clumps of RNA, which eventually produce more and more of themselves so as to form longer, and more suitable, RNA strands, which can eventually catalyze the synthesis of proteins, eventually forming a cell....
Okay, maybe my sequencing of events was not perfect, but please notice something about all of this: besides from some difficulties with the actual steps, one must realize that the steps are mere
possibilities (if that), and really only serve as an escape device for evolutionists.
Edited by sac51495, : typo
Edited by sac51495, : No reason given.
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