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Author | Topic: Micro v. Macro Creationist Challenge | |||||||||||||||||||||||||||
CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
Since you have put no bounds on the starting assumptions and you have made your definition of microevolution so broad, anything could be "explained".
Why not first start a thread on the definitions and differences between microevolution and macroevolution?
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CRR Member (Idle past 2267 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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CRR Member (Idle past 2267 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 2267 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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CRR Member (Idle past 2267 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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CRR Member (Idle past 2267 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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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
CRR at ~6200 years.
Sometimes I talk about millions or billions of years within the evolutionary frame of reference.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
Did you know the members of flat-earth society are evolutionist? At least some of them are.
Well in 2011 that included their president.The Flat Earth Society is an active organization currently led by a Virginian man named Daniel Shenton. Though Shenton believes in evolution and global warming, he and his hundreds, if not thousands, of followers worldwide also believe that the Earth is a disc that you can fall off of. Wolchover, N., Ingenious ‘Flat Earth’ Theory Revealed In Old Map, Live Science, 23 June 2011. Just checked, Daniel Shenton is still the president. Edited by CRR, : reference put in italics
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
In spite of what they often claim, creationists are anti-science.
So all these people are "anti-science"?Professor Dr Bernard Brandstater, Prof. Stuart Burgess, Professor Dr Ben Carson, Dr Raymond Damadian, Dr John Hartnett, Dr Raymond Jones, Dr Felix Konotey-Ahulu, Dr John Sanford, Dr Wally (Siang Hwa) Tow. Creationist scientist contributions - creation.com Not to mention all past scientists such as Faraday and Maxwell.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
Can any creationist give us a single reason why two microevolutionary events could not produce those two base differences?
Microevolutionary events could have produced those two base differences.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
Let's say that chimps, bonobos, gorillas, and orangutans are in the same kind and evolved from a common ancestor while humans are a separate kind and descend from a separate common ancestor. What would we expect to see when we compared the human genome to that of other apes? What we should see is that humans are genetically equidistant from other ape species. No, that's not what we should see. Even in the scenario you propose it's quite unlikely that humans are genetically equidistant from the other ape species. Starting from the initial separation the different apes should have drifted closer to or further away as they evolved within the kind. When we compare the human genome to any two other species it is almost certain that one of those will be genetically closer to humans than the other. E.g. Human vs dog vs banana. I bet the dog is closer genetically.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
Since you have put no bounds on the starting assumptions and you have made your definition of microevolution so broad, anything could be "explained".
For instance, according to Jorge Ruiz-Orera, et al, there are 634 human-specific genes, 780 chimpanzee-specific genes, and 1,300 hominoid-specific genes. If we assume a common ancestor with ~1400 more genes than modern humans or apes and assume that a gene deletion can be counted as microevolution then all non-homologous genes can be accounted for by microevolution. With a wave of the evolutionary wand everything is explained.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
RAZD writes:
CRR writes: When we compare the human genome to any two other species it is almost certain that one of those will be genetically closer to humans than the other. E.g. Human vs dog vs banana. I bet the dog is closer genetically. And why is that? Why, when we compare the human genome to any two other species is it almost certain that one of those will be genetically closer to humans than the other? Because the alternative is that humans are genetically equidistant from every other organism. So if humans are say 95% similar to chimps they would also be 95% similar to dogs and 95% similar to bananas. [edit: But would chimps be 95% similar to bananas?] Or were you asking why I think dogs would be genetically closer? Because we have in common many body tissues, organs, etc. that are built of similar proteins. From a common designer we would expect the genomes to contain many similar sequences. Edited by CRR, : as marked
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
They all use/used the scientific method to do science. They are scientists. If you didn't recognise the names you could have looked them up.
Science is a methodology, not a set of dogma. Any theory in science is open to question. If you deny that you are anti science.
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CRR Member (Idle past 2267 days) Posts: 579 From: Australia Joined: |
I don't see any evidence that those people are creationists.
Well let's just pick one. You can investigate the others yourself, beginning with the link I gave. Michael FaradayIn 1821, Faraday was accepted as a member of the Royal Societythe professional body where the foremost scientists exchanged discoveries and ideas. In a book on Faraday and electricity, Brian Bowers writes that ‘it seems likely that his religious belief in a single Creator encouraged his scientific belief in the unity of forces, the idea that magnetism, electricity and the other forces have a common origin. When Faraday retired from the Royal Institution after almost 50 years, he thanked those who had worked with him during those years. However, he was careful to ‘Thank God, first, for all his gifts’.
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