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Author | Topic: Micro v. Macro Creationist Challenge | |||||||||||||||||||||||||||||||||||||||
caffeine Member (Idle past 1052 days) Posts: 1800 From: Prague, Czech Republic Joined:
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I don't normally like to jump on when there's already a pile of other posters, but in this case I think everyone else has overlooked a fundamental misunderstanding:
That asked, the chances of the mutations required between human and primate, occurring in the right gene and often enough in the population to change the genome of the entire species, are next to naught. A specific mutation doesn't need to happen often to become characteristic of a species. It only needs to happen once. It can then spread throughout the population by inheritance. If it's an advantageous mutation, then it's likely to spread much more quickly than if not. When we talk about an advantageous mutation, all we really mean is one whose possessors are liable to leave more children in the next generation than those without. So each successive generation a higher proportion of the population will possess this mutated form of the gene; even though the mutation only happened once. That's what natural selection is. Edited by caffeine, : No reason given.
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CRR Member (Idle past 2270 days) Posts: 579 From: Australia Joined: |
If it's an advantageous mutation, then it's likely to spread much more quickly than if not
Advantageous mutations are subject to the cost of selection (Haldane's Dilemma) which limits how many advantageous mutations can be fixed in the time available. Since the publication of ReMine’s book in 1993, there has been no serious dispute that Haldane’s analysis (if correct) places a 1,667 limit, a severe limit, on human evolution, assuming 10 million years since the last common ancestor. Ian Musgrave in Haldane's non-dilemma does not dispute this limit but argues that humans are ~240 genes away from the last common ancestor and ~594 genes away from the chimp. However this ignores beneficial changes in the regulatory DNA which could well have been an order of magnitude, or more, higher. This limit has led to neutral theory which allows a much larger number of neutral mutations to be fixed in the same time. However most neutral mutations have no affect on the phenotype (that's why they're neutral) so we are really stuck with the 1,667 limit for humans, and perhaps 2,500 for chimps, explaining differences between the two species. These numbers reduce if the time to the last common ancestor is less than 10 million years.
A specific mutation doesn't need to happen often to become characteristic of a species. It only needs to happen once.
Even advantageous mutations are unlikely to be fixed unless the selection coefficient is fairly high. In most cases the selection coefficient is small and hence most advantageous mutations are likely to be lost. But you're right, it only needs to happen once; then be very lucky. In many cases drift will swamp selection.
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Coyote Member (Idle past 2134 days) Posts: 6117 Joined:
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From TalkOrigins:
Claim CB121: CB121: Haldane's DilemmaReligious belief does not constitute scientific evidence, nor does it convey scientific knowledge. Belief gets in the way of learning--Robert A. Heinlein In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers If I am entitled to something, someone else is obliged to pay--Jerry Pournelle If a religion's teachings are true, then it should have nothing to fear from science...--dwise1 "Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity. Liberals claim to want to give a hearing to other views, but then are shocked and offended to discover that there are other points of view--William F. Buckley Jr.
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Tangle Member Posts: 9512 From: UK Joined: Member Rating: 4.8
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CRR writes: Ian Musgrave in Haldane's non-dilemma does not dispute this limit but argues that humans are ~240 genes away from the last common ancestor and ~594 genes away from the chimp. However this ignores beneficial changes in the regulatory DNA which could well have been an order of magnitude, or more, higher. This limit has led to neutral theory which allows a much larger number of neutral mutations to be fixed in the same time. However most neutral mutations have no affect on the phenotype (that's why they're neutral) so we are really stuck with the 1,667 limit for humans, and perhaps 2,500 for chimps, explaining differences between the two species. These numbers reduce if the time to the last common ancestor is less than 10 million years. What is it about you creationist that make you have to distort what scientists say? Do you think we won't check? Musgrave actually says:
quote: Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London. "Life, don't talk to me about life" - Marvin the Paranoid Android "Science adjusts it's views based on what's observed.Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
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CRR Member (Idle past 2270 days) Posts: 579 From: Australia Joined: |
Ah, the ever "reliable" Talk Origins.
Since humans and apes differ in 4.8 10^7 genes ...
There aren't that many genes in humans and apes combined! I assume they meant 4.8 10^7 differences including point substitutions.
Only 1,667 nucleotide substitutions in genes could have occurred if their divergence was ten million years ago.
ReMine specifies beneficial, i.e. subject to natural selection, mutations, which can include point substitutions.
ReMine (1993), who promotes the claim, makes several invalid assumptions. His model is contradicted by the following: --The vast majority of differences would probably be due to genetic drift, not selection. --Many genes would have been linked with genes that are selected and thus would have hitchhiked with them to fixation. --Many mutations, such as those due to unequal crossing over, affect more than one codon. --Human and ape genes both would be diverging from the common ancestor, doubling the difference. --ReMine's computer simulation supposedly showing the negative influence of Haldane's dilemma assumed a population size of only six (Musgrave 1999). --The vast majority of differences would probably be due to genetic drift, not selection.Which is as I said. However genetic drift applies to neutral mutations which by definition don’t affect the phenotype, hence they are not significant for explaining differences between humans and chimps. --Many genes would have been linked with genes that are selected and thus would have hitchhiked with them to fixation.That would actually tend to limit genetic drift to that of actively selected genes. Since ReMine is talking about 1670 beneficial mutations with a much smaller number being in progress at any time this is not going to be significant. --Many mutations, such as those due to unequal crossing over, affect more than one codon.Actually I’m not clear what he’s getting at here. Crossing over is a mechanism to partially randomise the distribution of existing genes within the gametes. --Human and ape genes both would be diverging from the common ancestor, doubling the difference.Yes. That’s not disputed. It could even be a little higher. --ReMine's computer simulation supposedly showing the negative influence of Haldane's dilemma assumed a population size of only six (Musgrave 1999)Actually that is a criticism of ReMine’s use of David Wise's (dwise1?) program MONKEY and is irrelevant to ReMine’s calculations. Musgrave admitted it took him a couple of hours to identify what the error was. However it does also illustrate a flaw in these programs in that they allow the entire population to be replaced with the most successful variant in a single generation. Such programs therefore don’t simulate realistic biological populations. (Please note I have never used MONKEY myself and I'm going on what is in the TO site)
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CRR Member (Idle past 2270 days) Posts: 579 From: Australia Joined: |
Getting at the number of beneficial mutations in regulatory genes that have been fixed by natural selection is a lot harder, but it seems like around 100 regulatory genes may have been selected (Donaldson & Gottgens 2006, Kehrer-Sawatzki & Cooper 2007). The conclusions from the ENCODE pilot project were published in June 2007 and a lot has changed since then. In note [3] Musgrave says "Current evidence is that around 1.2% of the genome codes for protein, about the same amount for structural RNA and another 5% for regulatory sequences." So even in 2007 we could expect for each new gene 4 times as much change in the regulatory DNA. It's likely the real number is much higher than the 100 identified in 2007. And as I pointed out each new gene probably resulted from a number beneficial mutations. Actually, are evolutionary mechanisms even sufficient to produce over 100 new genes in the time available?
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Tanypteryx Member Posts: 4444 From: Oregon, USA Joined: Member Rating: 5.1 |
--The vast majority of differences would probably be due to genetic drift, not selection. Which is as I said. However genetic drift applies to neutral mutations which by definition don’t affect the phenotype, hence they are not significant for explaining differences between humans and chimps. I have seen you make this statement several times about neutral mutations. This is incorrect. Neutral mutations are neutral with respect to fitness, they are not selected out of the population. They may indeed affect the phenotype without being selected for or against. At some future time the changes to the phenotype may be affected by natural selection.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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dwise1 Member Posts: 5952 Joined: Member Rating: 5.2 |
My page about MONKEY is at cre-ev.dwise1.net/monkey.html. I have also written about it in this forum, so you could do a search.
Such programs therefore don’t simulate realistic biological populations. Neither WEASEL nor MONKEY were ever intended to. I highly recommend that you read my MONKEY page before you make more false assumptions. When Dawkins described WEASEL, I couldn't believe it, so I had to test it. Since Dawkins didn't provide any source code (I think it was a form of BASIC running on a MacIntosh), the only way I could test it was to write my own. In order for it to run as exactly like his as possible, I used his description of the program to come up with a specification for mine. I wrote it in Turbo Pascal, since that was what I was working in at the time (1990). It took Dawkins' program the lunch hour to run, but I think that was because he used an interpreted language. Mine succeeded in less than a minute. I ran it repeatedly and it succeeded repeatedly, every time without fail. I still couldn't believe it, so I calculated the probabilities involved. As improbable as each individual step is, the probability that every single step would fail becomes smaller and smaller until it is virtually impossible for it to fail. I wrote those calculations up in a text file, MPROBS.DOC, which I included in a PKARC package and uploaded it to CompuServe. The rest is history, including the part where I ported it over to C. Again, it is not a simulation of evolution! Rather, it is a comparison of two different selection methods. Re-read the first half of Chapter 3, "Accumulating Small Changes", from Dawkins' book, The Blind Watchmaker, where he describes two different kinds of selection to use to get a desired string:
So what WEASEL and MONKEY do is to compare how well those two selection methods work by giving them both the same problem to solve. Everything is kept the same except for the selection method. Single-step selection fails abysmally while it is virtually impossible for cumulative selection to fail. And the probability calculations in MPROBS explain why. I recently added to the end of the page a brief discussion of programs which do try to model evolution. I also found that some creationists misrepresent how WEASEL works; I discuss that too. If you want to claim that Royal Truman is correct, then I invite you to show me in my source code and in my probability calculations where I am supposed to have done what he claims we do. Like I say, "Everybody's got something to hide, except for me and my monkey!" Keep in mind that when I wrote MONKEY, we were still using XT clones. Most PCs now are at least hundreds of times faster, if not thousands of times. So when you run MONKEY, it will appear to succeed instantaneously. In order to observe the progressing towards and regressing away from the goal, pick a smaller number of offspring generated per iteration. Here is Ian Musgrave's email to me about it back when all this was going down. As you can see, that was nearly 20 years ago. I remember having received a xerox copy of what Remine wrote about me and my MONKEY and I remember being amazed at how much he had misunderstood it. BTW, I had written MONKEY about a decade before this and posted it in a library on CompuServe where it was constantly downloaded at least once a month for years thereafter. I explicitly asked for feedback and got none except that my numbering of the Markovian chain steps in MPROBS was off by one, and spurious complaints about teleological assumptions in my fitness test which both I and even Dawkins in his original presentation discussed and showed to be irrelevant -- ie, since the single-step selection model made the exact same fitness test, when why was it such an abysmal failure when cumulative selection was such a resounding success?
quote: The problem he reported in the PS was apparently an overflow error in the Turbo Pascal startup code, probably in a timer calibration loop, because PCs had gotten too fast. I was able to find a patch for it and fixed it. That's covered in the first section of my MONKEY page, Development History and Issues. Again, that is at cre-ev.dwise1.net/monkey.html. Edited by dwise1, : Changed subtitle
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CRR Member (Idle past 2270 days) Posts: 579 From: Australia Joined: |
Thanks for that information. It's pretty much what I inferred from the page in TO.
Neither WEASEL nor MONKEY were ever intended to simulate realistic biological populations. Again, it is not a simulation of evolution! If anyone says otherwise I refer them to you. Edited by CRR, : edit
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dwise1 Member Posts: 5952 Joined: Member Rating: 5.2 |
But will you now read the source and see what it's really about?
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CRR Member (Idle past 2270 days) Posts: 579 From: Australia Joined: |
No need. It was only that TO mentioned it and it has now been shown to not be relevant.
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dwise1 Member Posts: 5952 Joined: Member Rating: 5.2
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But single-step selection versus cumulative selection is very relevant. As such, it needs to be examined.
I forget. Were you one of those deluded creationists who tried to force single-step selection upon evolution with a terminally false creationist probability argument? Sorry, but it's hard to keep you all apart.
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
CRR writes: --Many genes would have been linked with genes that are selected and thus would have hitchhiked with them to fixation.That would actually tend to limit genetic drift to that of actively selected genes. Since ReMine is talking about 1670 beneficial mutations with a much smaller number being in progress at any time this is not going to be significant. It would tend to drive more beneficial mutations to fixation, which is the whole point. Selective sweeps decrease the cost of natural selection. Much of Haldane's conclusions have been shown to be inaccurate, as Haldane himself anticipated.
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
Hi :Tangle
Tangle writes: Btw, it's always useful to know with a newbie creationist, how old do you think the earth is? A lot older than you do. I just had to answer that question. God Bless,"John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."
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Tangle Member Posts: 9512 From: UK Joined: Member Rating: 4.8
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ICANT writes: A lot older than you do. I remember, your the one that thinks it's trillions of years old! So we have Faith at 6,000 years, CRR at the normal 3.4bn (I think) Dredge says somewhere between 6,000 and billions of years, and you at trillions. It as confusing as remembering all your different and contradictory religious beliefs. You should really have it in your signatures so we know what versions we arguing against. And my question about the Mountains of Ararat being where the Ark set down but you claiming they were only formed 100 years later?Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London. "Life, don't talk to me about life" - Marvin the Paranoid Android "Science adjusts it's views based on what's observed.Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
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