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Member (Idle past 5940 days) Posts: 563 From: Brisbane, Australia Joined: |
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Author | Topic: Twin-Nested Heirarchy | |||||||||||||||||||
Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
But what they (the evilutionists) don't tell you is that similarities are not evidence of common descent. They can also be indicators of common design. Well of course we don't tell people that, it's not true. We are under no obligation to recite your propaganda for you.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
The analysis assumes that similarity is evidence of common descent. No. Common descent (plus what we know from the fossil record) makes certain predictions about what we should see if we applies these techniques. We can, of course, test these predictions without assuming common descent to be true.
In fact, when these techniques were developed, the creationist response should have been: "Whoopee! Those evilutionists predict that birds should have genes closer to crocodiles than to anything else --- now we're gonna show em! To the laboratory!" For some reason this didn't happen, possibly because of intellectual cowardice but most likely because they don't actually have laboratories. Now, once one has been convinced by this and all the other evidence that evolution is correct, then one can use it to construct cladograms. It is not the cladograms themselves which are offered as proof of common descent, but rather that the theory predicts the data on which the cladograms are based.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
Really? Prove it! Try: Hedges, S. B., and L. L. Poling. 1999. A molecular phylogeny. Science 83:998-1001 Kumazawa, Y., and M. Nishida. 1999. Complete mitochondrial DNA sequences of the green turtle and blue-tailed mole skink, statistical evidence for archosaurian affinity of turtles. Mol. Biol. Evol. 16:784-792 Summary: birds are closer genetically to crocodiles and turtles than to anything else; crocodiles and turtles are closer genetically to each other and to birds than to other reptiles. --- Here's another example. Evolutionary theory predicts that lobe-finned fish should be genetically closer to humans than to ray-finned fish. Guess what, it's true!
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
But, why couldn't common design also result in such a pattern in the data? By "common design" I had understood you to mean designs for a common purpose having common features. As you put it in your OP:
[W]e should not be surprised that organisms that look like people have genes similar to those of people. And if that is your reasoning, then we should be surprised that the lobe finned fish are closer to humans than to the ray-finned fish, shouldn't we? Unless we are evolutionists, in which case that's exactly what we should expect. --- If you just mean that perhaps God decided to make all the creatures in such a way that their genes would conform exactly to the theory of evolution, then he might have done, in the same way that he might have appointed angels to push the planets round in exact conformance to the theory of gravity. But you cannot claim the conformity of genetics to the theory of evolution as evidence of common design, any more than you can claim the conformity of planetary orbits to the theory of gravity as evidence for angels. Because the hypothesis: "All creatures has a common designer" does not predict the observation: "All their genes will conform exactly to the predictions of the theory of evolution." Whereas the theory of evolution does predict that. Hence, the observation that all creatures' genes conform to the predictions of the theory of evolution is evidence for the theory of evolution and is not evidence for "common design". Compatible with it, yes, under the additional hypothesis that God made the world as a big hoax to fool scientists, something that, I think, neither of us believes. "Raffiniert ist der Herr Gott, aber boshaft ist Er nicht", said Einstein --- "The Lord God is subtle, but He is not malicious." Edited by Dr Adequate, : No reason given.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
Yes, the birds-and-turtles thing was something of a poor choice of example on the part of mark24, because the place of turtles within Reptilua has long been controversial --- not enough fossils, you see.
On the other hand, the crocodile-bird affinity is, from the fossil record, indubitable --- they're both definitely archosaurs, and if turtles aren't archosaurs, then they're the only living archosaurs.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
It's just lice losing information as they evolve within the lice kind, and likewise for the gophers. Something that creationists have proved by a rigorous process known as "wishful thinking".
I have no reason to believe you when you continually assert that simply because you can use molecular techniques accurately on some piece of microevolution, that it will automatically work on a broader scale too. But while the assumption of common descent may actually be true for different lice species and different gopher species, you have to make a leap to assume it will be true for all life. As I have pointed out, we do not have to assume common descent in order to use these genetic similarities as evidence for common descent. Rather, we have to observe that common descent (together with the fossil record) predicts the nature of these similarities. Accurately.
I know that (well, at least Doddy knew that)! But the example is still valid because it shows that short sequences of non protein-coding RNA, even in the simple prokaryotes, can regulate morphology. But not that all of them do! Non-coding sections of DNA that have a function tend to be highly conserved. Most eukaryote DNA is not. This seems to be something of a side-issue.
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
Because I'm going to draw a completely arbitrary line in the sand where you implicate that evolution between kinds can occur, therefore showing a relationship between humans and chimps. Or, because I'll adhere to the bronze age belief that the world is only 6000 years old, and that no amount of evolution could do such things. Oh, it was just a leg-pull.
I'd like to thank crashfrog, Mr A, bluegenes and mark24 for making some great posts in this thread. You've been very helpful for me in writing the EvoWiki page on Nested Hierarchy. Dr A. If you wanted help, you could just have asked for it, you know?
Molecular Phylogeny
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Dr Adequate Member (Idle past 315 days) Posts: 16113 Joined: |
1. Firstly, creationists will always deny that junk DNA is in fact junk. They will say that just because we have no idea what it does, that doesn't mean it does nothing. I can't address this in the article, so is there another way that I can 'uncouple' biochemistry from anatomy, or otherwise validate this method? Well, in the first place most non-coding DNA is not conserved. In the second place, I believe I'm right in saying that people have made experimental organisms where they've snipped out large chunks of nonconserved noncoding DNA, with the organisms being none the worse for it.
2. The 'assumption' of common descent, rather than common design. Creationists seem to think that designed objects, like cars, can be categorised in a nesting manner too. So they don't see nesting as evidence of anything. I've currently got this: Well, your answer looks good to me. I don't think I can add much to that except the words: "Oh no they don't", or perhaps: "Bollocks".
By the way, I do like that page. I especially like the cladograms contrasting cladogenesis and orthogenesis. Do you have the copyright info for those pictures? I believe that this exquisite example of the illustrator's craft was composed by one of the more talented of the new generation of artists, a young man who calls himself "Dr Adequate", using a highly sophisticated piece of software that those of us "in the know" refer to simply as "Microsoft Paint".
Do you think contributing to two wikis would be too much for you? EvoWiki could always do with more contributors. Otherwise, I'd just ask you to link to some of our pages in your external links sections. For example, we have a very (very!) comprehensive article on Archaeopteryx. In fact, it's bordering on unreadable, being authored by a paleornithology student. I'll certainly be linking to the SkepticWiki in future! Well, the SkepticWiki, like other wikis, is non-profit, non-copyright, take anything you like from it. That way, if I write an article on evolution, I can contribute to two wikis for the effort of contributing to one. However, I do think, strange that it may seem, that we ought to duplicate our efforts. When I'm writing an article like that, I look at talkorigins and the EvoWiki last, to see if there's anything I've missed. It's good that people come at it from different perspectives and different angles, using different examples and references. I see what you mean about the Archaeopteryx article. Here's mine. Sometimes, a picture really is worth a thousand words. --- P.S: Not only is the phrase "twin-nested heirarchy" not an actual term in biology, but even if it was, it would be spelt "hierarchy". Edited by Dr Adequate, : No reason given.
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