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Junior Member (Idle past 5245 days) Posts: 27 From: Adelaide, Australia. Joined: |
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Author | Topic: "The Edge of Evolution" by Michael Behe | |||||||||||||||||||||||||||||||||||||||||||
Kaichos Man Member (Idle past 4487 days) Posts: 250 From: Tasmania, Australia Joined: |
G'day Drosophilla.
Utter miscomprehension on how probability stacks up in evolution. What you don't appreciate is that evolution works on the power of accumulation. I'm sure you are aware that I started a thread entitled "Adding information to the genome". In it I tried (and failed, for the most part) to get some evolutionists to agree to an amount of new information needed to be "seen" by natural selection. My argument was simple: up until natural selection can "see" a de novo genetic structure it can only be built by random forces. Note that this argument does not ignore natural selection; it merely attempts to calculate the amount of new information needed to enable natural selection to enter the equation. A quote from your referred website: "But this argument contains a hidden assumption: that the entire page has to be typed at once, or that the entire amino acid sequence has to be assembled at once. What if you can build it piece by piece?" Same problem. Natural selection can do nothing until there's phenotypic modification. Of course, that can be caused by a single nucleotide switching an existing gene on or off, but that's not creating new information, it's merely modifying existing information. Having said this, I should say that a level should be established in the creation of our gene for a human enzyme at which natural selection plays a role (at that point probabilities become meaningless because there is a directive force). Would natural selection be able to "see" a half-functional gene? Then the probability reduces to 1 in 4500 divided by 20,000. It's still workably impossible, even with natural selection factored in. "Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy." Charles Darwin
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Kaichos Man Member (Idle past 4487 days) Posts: 250 From: Tasmania, Australia Joined: |
If all they did was simply "tweaked" their models until they got the result they wanted instead of learning about the problems in their design then they'd never get a successful design and there would be no point to modelling. Precisely. So how would you learn about design problems in a program modelling evolution? By finding evolution doesn't happen, of course. And what do you do in such a situation? Well the program is obviously defective, so you work on it until it does show evolution happening. It's always easy enough to justify an adjustment to a variable. Dawkins Weasel (yes, I know, it's a toy) is a prime example of this. I mean, what exatly did the "correct letters" represent? Single nucleotides? Wouldn't be seen by natural selection. Genes? Can't be created by random processes. But Dawkins was smart enough to refuse to say what they represented. "Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy." Charles Darwin
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
Dawkins Weasel (yes, I know, it's a toy) is a prime example of this. I mean, what exatly did the "correct letters" represent? Single nucleotides? Wouldn't be seen by natural selection. Genes? Can't be created by random processes. But Dawkins was smart enough to refuse to say what they represented. They didn't represent anything. It was not a model for natural selection. It was a simple way of explaining how cumulative selection can work on inherited traits to 'climb mount improbable'. There are only a small number of pages in the book which discusses the weasel, and it does explicitly state that it is not a model of biological evolution in any interesting way. Edited by Modulous, : No reason given.
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Percy Member Posts: 22388 From: New Hampshire Joined: Member Rating: 5.2 |
Hi Kaichos Man,
You misunderstood Drosphilla's reply. Your argument is that neutral mutations, since they produce no phenotypic change, cannot be selected. We all agree with you, including Drosophilla. He was talking about mutations that *do* produce phenotypic change and that *are* acted upon by natural selection, explaining that small changes gradually accumulate into larger changes. This includes the gradual accumulation of neutral mutations where at some point one additional mutation does cause phenotypic change. As has been explained, you seem to be misunderstanding Kimura as saying that so few mutations produce phenotypic change that they cannot be a factor in evolution, and that's not what Kimura said. The Kimura quote you're so fond of talks only of change at the molecular level, not at the phenotypic level.
Kaichos Man writes: Of course, that can be caused by a single nucleotide switching an existing gene on or off, but that's not creating new information, it's merely modifying existing information. Modifying existing information creates new information. If we label the original information "a", and we modify it to become "b", then "b" is new information. Depending upon the specific circumstances "b" might represent more or less information than "a", but it is definitely new and different information that did not exist before. --Percy Edited by Percy, : Add clarification to first paragraph.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Single nucleotides? Wouldn't be seen by natural selection. This is just more empty babbling showing how little you know about biology. The mutation behind sickle cell anaemia is a single nucleotide substitution. Do you really think that sickle cell anaemia isn't seen by natural selection? There are many other examples, if you think single nucleotide changes cannot form the basis for significant natural selection then you clearly know nothing about evolutionary biology, molecular biology or developmental genetics. TTFN, WK
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Percy Member Posts: 22388 From: New Hampshire Joined: Member Rating: 5.2 |
Kaichos Man writes: Precisely. So how would you learn about design problems in a program modelling evolution? The "design problems" of organisms are found in evolutionary modelling programs at each generation when selection is performed. Just as in the natural world where the least well-adapted organisms either fail to reproduce or at least reproduce less successfully, in an evolutionary modelling program the "organisms" that are least well-adapted to the simulated "environment" produce fewer or no "offspring."
Dawkins Weasel (yes, I know, it's a toy) is a prime example of this. I mean, what exatly did the "correct letters" represent? Single nucleotides? Wouldn't be seen by natural selection. Genes? Can't be created by random processes. But Dawkins was smart enough to refuse to say what they represented. I guess I have the same reaction to this as Dr Adequate: "Good grief, are you still being wrong about that?" I see that Modulous has explained this yet again, but this has been explained to you so many times in so many different ways by so many different people that I'm not sure there's any point in attempting yet more explanations. --Percy
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NosyNed Member Posts: 8996 From: Canada Joined: |
Please read post one here:
Message 1 and answer the questions there. You have not defined information in a useful way, btw.
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Drosophilla Member (Idle past 3641 days) Posts: 172 From: Doncaster, yorkshire, UK Joined:
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Hello Kaichos:
Same problem. Natural selection can do nothing until there's phenotypic modification. Of course, that can be caused by a single nucleotide switching an existing gene on or off, but that's not creating new information, it's merely modifying existing information. This is utter babble! Please try to remember that Natural selection will not actively select AGAINST a neutral modification (i.e. a change that does not effect a phenotypic change. Most changes to base pairing won't in fact cause a phenotypic change - and you are trying to use those figures in your statistics to say these 'don't count'. But because a change that doesn't cause a phenotypic change won't be selected against, it naturally means that change remains in the gene pool....and can later change again - this time maybe to one that does cause a phenotypic change. In this scenario we have a two-step requirement - and what you are in effect saying is that unless it happened all at once it is too improbable. But if the first step causes no significant change from a point of view of Natural Selection, then it will remain in the pool - and be there when the next (possibly real effect change takes place). This can be the case for numerous changes. If you need a twenty step link to a beneficial phenotypic change, then as long as the first 19 steps are either beneficial OR NEUTRAL, (which the majority of single step changes are), then the accumulating changes will not be taken out. Only if intermediate steps are disadvantageous to Natural Selection within the pertinent environment, will the change be actively selected against and weeded out. Very simple really: Changes that are neutral or positive will remain. If the change is positive then it will be actively selected for, if neutral the possessing organism has the normal chances of passing the neutral change on to offspring, allowing that change to continue to exist and maybe then in future mutating to the next change. If that is then a positive one, it will be actively selected for survival. This is what is meant by the power of accumulation. did you try Michael Wong's probability widget where 10 dice are rolled all at once (repeating every two seconds). Michael reckons that you should get all ten to hit six at the same time approximately once a year. Then he provided a second widget game. This one rolls ten dice but only one at a time, with the next one rolling only after the previous one hit a six (the equivalent to a later mutation on the back of an earlier neutral or positive change). You will find that this way you will hit all ten sixes in around 60 or so turn taking about 30 - 50 seconds...the power of accumulation. You are assuming evolution throws all the dice together, when in fact it throws them one by one. The link, again, for those interested in trying his widgets is: Probability - (Entire article as one page) The widgets are under item 3 a third of the way down. As RAZD would say...."Enjoy"
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
But because a change that doesn't cause a phenotypic change won't be selected against, it naturally means that change remains in the gene pool.. I think you are going over the top here. In the vast majority of cases such changes probably won't remain in the gene pool as low frequency alleles which aren't subject to selection are prone to be lost due to drift. That certainly doesn't mean that they can't remain in the gene pool, but it is far from being a sure thing. I find your hypothetical 19 neutral potentiating steps scenario almost totally ridiculous. Can you give us any evidence of such a thing occuring? If you look at Lenski's long term evolution experiment the evolution of citrate metabolism took more than 30,000 generations and that seems to have only involved 2 mutations, neither one of which may be neutral (Blount et al., 2008). Neutral changes can rise to fixation through hitchhiking, but for 19 to do so before a beneficial mutation can arise seems to be stretching things a bit. I can quite easily believe that in a dynamic evolving genome there will be proteins whose evolutionary trajectory has been substantially shaped by chains of interaction with, at the time, selectively neutral mutations with a potentiating effect, which is what Thornton's research shows, and that this could encompass dozens of selectively neutral changes. I find the idea of 19 seperate neutral mutations arising and being maintained at sufficiently high levels to allow 1 beneficial mutation to arise to be doubtful. The 2nd dice model seems to be exactly the sort of locking scenario that everyone wrongly accuses Dawkin's weasel program of being. You seem to ignore the fact that neutral mutations have no reason to be considered locking, neither do beneficial mutations in most cases but it is a more reasonable assumption. The Weasel still seems a better demonstration. TTFN, WK
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Kaichos Man Member (Idle past 4487 days) Posts: 250 From: Tasmania, Australia Joined: |
It was a simple way of explaining how cumulative selection can work on inherited traits to 'climb mount improbable' But it is precisely the "inherited traits" that are so misleading and dishonest. SNPs won't be seen by selection (unless they alter existing information). Genes will be seen by selection, but they are too complex to be built by random processes. Mt Improbable can't be climbed because the inheritable traits are either invisible to selection or too complex to occur without selection. Dawkins program is akin to me flapping my arms and saying "There, feel the air pressure under your hands? That's how you fly- it's easy." "Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy." Charles Darwin
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
SNPs won't be seen by selection (unless they alter existing information). Well clearly they do alter it by any sane standard. The extent to which they do and whether it constitutes a gain or loss of information would depend on how you are measuring information, something you still seem loathe to tell us. You seem to be saying that neutral snps won't be seen by selection, whcih is true but has no actual bearing on the discussion.
Mt Improbable can't be climbed because the inheritable traits are either invisible to selection or too complex to occur without selection. A claim with no evidence to support it, compared to the masses of evidence for SNPs with observable phenotypes, including beneficial ones. TTFN, WK
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Kaichos Man Member (Idle past 4487 days) Posts: 250 From: Tasmania, Australia Joined: |
The "null string" consisting of no DNA contains no information. Blimey. Who came up with that? Rene Descartes? I would define genetic information as: "A DNA sequence that plays a role, direct or indirect, in the formation or function of an organism". No doubt this will precipitate a small avalanche of examples that are clearly information, but don't fit the definition. "Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy." Charles Darwin
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
No doubt this will precipitate a small avalanche of examples that are clearly information, but don't fit the definition. It seems more likely to bring about an avalanche of people pointing out that this is a totally useless definition in terms of actually measuring information. TTFN, WK
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Kaichos Man Member (Idle past 4487 days) Posts: 250 From: Tasmania, Australia Joined: |
This is utter babble! Is it, indeed? Well let's take a look at it. I wrote: "Natural selection can do nothing until there's phenotypic modification" You wrote: "Natural selection will not actively select AGAINST a neutral modification (i.e. a change that does not effect a phenotypic change" Hmm. The babble appears to be contagious.
This can be the case for numerous changes. If you need a twenty step link to a beneficial phenotypic change, then as long as the first 19 steps are either beneficial OR NEUTRAL, (which the majority of single step changes are), then the accumulating changes will not be taken out. You appear to be advocating the creation of complex novel genetic structures by random (non-selective) processes. Fine- Kimura believed in that. The trouble is, if you want to create, say, a gene, you'll need about 1300 'neutral' mutations, not 20. And given that for every 175 mutations, about 3 of them will be deleterious, you're not going to get very far. "Beneficial" mutations are too rare to calculate, according to Kimura. "Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy." Charles Darwin
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
You appear to be advocating the creation of complex novel genetic structures by random (non-selective) processes. Fine- Kimura believed in that. No he didn't, please provide a quote to support this blatant misrepresentation. What Kimura believed was that the vast majority of evolution, not adaptive evolution, was neutral. In other words most single nucleotide polymorphism changes that represent the majority of variation in the genome do not produce functionally significant effects (Kimura, 1989). Similarly he may extend this to the grosser phenotype and suggest that a number of gross morphological variations may be essentially neutral. Such neutral variation is, according to Kimura, kept in the population by a dynamic balance of continuous mutation and extinction of polymorphic alleles and may become fixed by genetic drift. Kimura's 'survival of the luckiest' describes the mode, in a statistial sense, of evolution not the whole of it in the same way that Gould points out that the mode of life on earth is bacterial. Kimura does not deny the existence of adaptive evolution, he just points out that most genetic variation is not governed by it.
"Beneficial" mutations are too rare to calculate, according to Kimura. Given your previous record I tend to doubt it, but feel free to show us precisely where he wrote this. TTFN, WK Edited by Wounded King, : No reason given. Edited by Wounded King, : No reason given.
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