On Friday, April 19, 2013 9:59:34 AM UTC-4, Bruno Marchal wrote: > > > On 18 Apr 2013, at 22:05, Craig Weinberg wrote: > > > > On Thursday, April 18, 2013 1:29:29 PM UTC-4, Brent wrote: >> >> On 4/18/2013 8:15 AM, John Clark wrote: >> >> On Wed, Apr 17, 2013 meekerdb <[email protected]> wrote: >> >> > It's been proposed that the susceptibility to mutation is itself a >>> characteristic subject to natural selection. >>> >> >> If a animal is undergoing stress (too hot, too cold, too thirsty, too >> hungry whatever) that means there is something about it that is not well >> adapted to its environment; I can imagine a gene that in times of stress >> would switch on and produce a chemical that increases the rate of random >> mutation in the genes of the offspring of that stressed animal. Most of the >> offspring would have mutated in the wrong direction and die but they would >> have probably died anyway because they would have been as poorly adapted as >> there parent was, but if the mutational effect was not too strong (even if >> it's in the right direction you can change things too far) it could >> increase the likelihood that at least one of its children would be better >> adapted than its parent. However I maintain that such a stress induced >> mutation producing gene has had no significant effect on the history of >> life, at least not in animals that reproduce sexually. >> >> >> That's a kind of Lamarckian adjustment of mutability. What I was >> referring to is simple Darwinian adjustment of mutability. There are error >> correcting mechanisms for DNA reproduction. Suppose they worked perfectly: >> then there would never be any genetic variation and when the evironment >> changed the species would go extinct. But if they had a slight error rate >> then there would develop a range of genetic diversity that might, under >> environmental change, result in survivors or even new species. So on >> strictly Darwinian theory the DNA error correction may be selected to be >> less than perfect. >> > > How does a deterministic universe invent something which is intentionally > less than perfect? I'm not saying that it couldn't, or didn't, but why > would there really even be any possibility of volatility built into physics > in the first place? What, in a deterministic universe, constitutes an > 'error'? > > > > A deterministic reality might be unable to make an error at the "bottom > level", but if it can emulate high level complex processes, like running > some complex software, and such software can make an error with respect to > the goal (like "survive"). Look at some youtube "crash investigation" > showing why today some plane crash are due to computer errors. The error > can have multiple origin, hardware or software. > Likewise it is reasonable for a biologist to say that when a DNA > polymerase introduces an unwanted supplementary nucleotide, it is making an > error. In fact living cells contains a lot of error correction code to > handle such cases, with 'error' taken in a sense similar to the one used in > computer science. This illustrates that some errorless low-level can > support higher level errors. > > Bruno >
It seems like you are bringing in empirical evidence of errors in the real world and using that to justify the expectation that at some point between low-level and high-level, this 'error' potential emerges as a condition of complexity. What I am asking for though is precisely that this point be explained by theory. What is the theory of the emergence of the first error? Craig > > > > > > > > Craig > > >> Brent >> >> >> Such a stress-mutation gene has never been found in a sexual animal and >> it's easy to see why. In sex all the genes are not inherited in one big >> package but are shuffled around with the genes of the other parent, so a >> animal that was lucky enough to inherit the good genes produced by the >> hypothetical stress-mutation gene but not the stress-mutation gene itself >> would do just as well or better than a animal that got both the good genes >> and the stress-mutation gene that is no longer active because the animal is >> no longer under stress. So even if such a stress-mutation gene did occur in >> one individual in a population it would vanish in just a few generations >> from the gene pool. Natural Selection doesn't figure "I better keep that >> stress-mutation gene because even though there is no stress now that could >> change and such a gene might come in handy in the future". Evolution has >> no foresight and can't think and all that matters to it is what's happening >> right here right now. >> >> John K Clark >> >> >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Everything List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/everything-list?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2013.0.3272 / Virus Database: 3162/6252 - Release Date: 04/17/13 >> >> >> > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > To post to this group, send email to [email protected]<javascript:> > . > Visit this group at http://groups.google.com/group/everything-list?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > > > http://iridia.ulb.ac.be/~marchal/ > > > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
