Evolution (Introduction)

by George Jelliss , Crewe, Thursday, April 16, 2009, 19:33 (5496 days ago) @ dhw

In the chinese dice-throwing analogy, when applied to the abiogenesis problem, the "10 heads in a row" represents the unlikely configuration that was the first self-replicating molecule. dhw cites DT saying that "To have living organization of organic molecules they have to be directed by a code filled with information. Where did the information come from?" This seems to suppose that the code pre-existed the earliest self-replicating molecules. In fact of course the code was part of the molecule. We now know that the code in DNA uses four bases. Perhaps the first replicating molecule only used two bases, and four was a later development. I throw this in as what seems a likely conjecture. - Darwin in Origin of Species did not concern himself with how life first originated because he had no evidence to throw light on that subject. But now that we know the chemical structure of DNA and many of the processes involved in cells we are in a better position to consider the subject. And we can envisage the theory of evoution by natural selection extending back further to the earliest self-reproducing molecules, or systems of molecules. Whether you could properly call these molecular systems "creatures" however seems doubtful. - It is true that "Espritch" like many biologists talks about evolution producing, assembling, building and using. However, as dhw admits, that form of language is not meant to imply any conscious purpose. dhw asks: "What, then, performed the producing, assembling, using, building?" He answers, wrongly, "Obviously they [the first "simple existing" things] did." - dhw talks about "the ability both to adapt to changing environments and to increase complexity" (his emphasis) as if these "abilities" were properties of living things. Humans with consciousness have the ability to adapt themselves to changing conditions. But this is what takes them out of the realm of natural selection. The adapting to changing environments is forced on life from the outside by action of the environment (e.g. colder climate favours those with hairier coats). Complexity arises, as in the haemoglobin example, from simpler components getting combined. These are not driven by some desire within the life-form to become more complex. - The statement from Espritch can be rephrased in non-operational form, something like this (I'm sure you could do better): "Haemoglobin is actually an excellent example of how evolution can result in the appearance of complex things; by the chance assembly of simple things with an existing functionality into more complex but still functioning things and then in subsequent stages of evolution resulting in those things coming together in a still more complex functionality." But you can see why this sort of contorted English is avoided!

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GPJ