Frequently Asked Questions: Abiogenesis (Biopoesis)
Advantages: No need for large pool of complex organic molecules to start; can be gradually added. Deftly avoids all questions of the sort 'where did the ribose come from' Disadvantages: No evidence nor plausible mechanism for 'genetic takeover.[NO EVIDENCE BUT THAT DOES NOT STOP THE WRITER FROM ATTEMPTING A JUST-SO STORY]' However, it should be noted that clays have been seen to catalyze a number of prebiotic reactions. Advantages: Can derive almost all modern metabolism; genetic (as opposed to chemical) inheritance does not become involved until quite late; most reactions are postulated to occur in, well, slime layers on the surface of rocks (pyrite). This both reduces the dimensionality and dilution problems associated with normal prebiotic chemistry, and provides an 'identity' for chemical organisms (i.e., 'self'= your rock). Disadvantages: Some slight evidence for the ur- cycle, but the chemistry is pushed well beyond the bounds of anything known today.[JUST-SO STORY] If he turns out to be right it will be an intellectual achievement ranking with the Theory of Relativity. My personal assessment is that the reactions have been severely strained to produce 'modern' compounds and pathways, while it seems far more likely that the chemical cycles that initially evolved may have looked nothing like what exists today. That is, this theory seems to be guided by biological preconceptions rather than chemical plausibility. Advantages: Obvious and direct relation to modern life. Polymers can act as catalysts for their own replication and can create what Eigen has called 'hypercycles' (Eigen, Naturwissenschaften, 65, 341 (1978) is the classic paper in this field). Disadvantages: 'Food' tends to be relatively unstable molecules (see, for example, Pace, Cell, 65, 531 (1991)) that are prepared in extremely low yield by prebiotic pathways currently known. [DOESN'T SEEM LIKELY, THEREFORE PREPARE FOR ANOTHER JUST-SO STORY] In order to get around this, there are a wide range of nucleic acid 'like' compounds that are proposed to have preceded real nucleic acids on the evolutionary stage (Joyce, Nature, 338, 217 (1989) for a brilliant review). I have posted the mini-FAQ in the hopes of providing some snippets of evidence for those who say there are none. Perhaps this will sway some of you, perhaps not. I have tried to avoid advancing or advocating specific mechanisms for abiogenesis because I still believe that the following should be enough for us all: Evolution is both a theory and a fact. In accepting this, we must follow its tenets to their logical conclusion. Organisms evolve; their lineages can be traced. Their lineages lead back to a cell. Just as all cells evolved from this cell, so this cell must have evolved from something. The cell must have evolved from some set of molecules. These molecules can be seen to evolve even today. All of the events that led from the molecules to the cell were governed by the theory of evolution. It is the same theory that governs the evolution of all organisms, indeed of all self-replicating systems. |
The final paragraph explicitly demonstrates the reason that abiogenesis is tied to Darwininianism.
Not really. It just pushes the problem back to where it's always been. Evolution requires self-replicating organisms, but nowhere are they required to be cells - self-replicating molecules fit the requirements of the theory of evolution perfectly, but the theory makes no claim that such self-replicators arose through purely abiogenetic processes, nor does it explicitly or implicitly require such. How the first self-replicators came about is fun to speculate about, but it isn't a part of the theory of evolution - so long as self-replicators exist, that theory is satisfied no matter whether it was abiogenesis, God, leprechauns, space aliens, or something else that created them.
But of course, you know this...
Cause and effect is invoked here but try and get them to apply cause and effect to the beginning of the universe and their gears start stripping.