From: Jon Roland <[address removed]>
To: [address removed]
Sent: Monday, February 23,[masked]:02:35 AM
Subject: Re: [philosophy-31] Darwin Misunderstood -Scientific American Magazine
The anniversary of Darwin gives occasion to discuss evolution and genetic processes, but it should be kept in mind that those genetic processes were unknown to Darwin, and progress in the field makes evolution a more complex process than most people appreciate. Here are a few of those complications:
1. Mutation is not just a matter of copying errors or radiation damage. Chromosomes can get split, stitched together, doubled, or lost altogether.
2. Mitochondria also have genes that propagate only along the female line, and randomly mutate.
cytoplasm plays a role in genetics that is not yet well understood, but all the action is not in the chromosomes. You don't get a copy of a dinosaur just with the dinosaur DNA in the chromosomes. You also need at least closely related cytoplasm and mitochondrial DNA.
4. DNA can pass between cells of different species through other than meiosis. It can be injected by infective microorganisms and viruses, among other means.
5. The expression of genes, even if not suppressed by other genes or processes, is subject to random error. Our chromosomes contain less than 10^-11 of the information needed to specify the microstructure of adult organisms. The variations are neither the result of nature (genes) nor nurture (environment influences), but of chance. Identical twins have the same DNA when born that make it likely (but not certain) they will have fingerprints, but not identical fingerprints. Genes guide what is is largely a self-organizing,
6. Our DNA continues to change as we grow, so that by adulthood different cells have slightly different DNA, and identical twins no longer have perfectly identical DNA.
7. Besides the selective pressure from the natural environment, competitors, and food or prey, or from sexual selection, there is also social selection of individuals advantageous to the group, which seems likely to be important for primates in general and humans in particular.
8. Genetic change can involve both replacement of genes and the overlaying of their expression, which is how we retain remnants of ancestors, or the recapitulation of evolution in embryos. Each gene and more, the expression of it, involves an investment of energy and risk, that to be sustained requires a payoff in reproductive success, lacking which it will tend to disappear, slowly if it has little impact on reproductive success, and faster if the negative effect is large.
9. As has
been pointed out, cooperation can be selected for as much as competition. That is how social species occur, and most mammals and birds are social to some degree. As Wilson and others have pointed out, adults are genes' way of producing more genes of the same line, and it makes sense for the group for individuals to sacrifice their own reproductive success to protect the progeny of their close relatives.
10. What we call morality and constitutional government is largely an expression of what is rational for social groups whose individuals have certain capabilities. It is not arbitrary or accidental, but an optimal strategy that we can expect will reappear anywhere in the Universe that a social species roughly like ours does. The details of this conjecture remain to be supported by sufficient evidence and analysis, but I am confident this will be achieved in due course.
Jon Roland 512/[masked]
2900 W Anderson Ln C[masked], Austin, TX 78757 www.jonroland.org
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