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Quasar6 -> RE: Mosaic disprove Common ancestry? (9/12/2007 12:26:43 AM)
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quote:
ORIGINAL: Jhud quote:
Here are the people: B1 (Brother 1) : Has hair, but not backbone. B2 (Brother 2) : Has a backbone, but no hair. C1 (Cousin 1) : Has both a backbone, and hair. Any one of the following must be true before the nested hierarchy is violated: * No ancestor of B1 has hair. * No ancestor of B2 has a backbone. * No ancestor of C1 has hair. * No ancestor of C1 has a backbone. The fact that B1 and B2 are more closely related, yet C1 shares traits they don't share with each other DOES NOT VIOLATE THE NESTED HIERARCHY. If you knew what a nested hierarchy WAS, you would know this. You don't. Sorry to interject here, but doesn't evolution assume that at some point that our ancestors at didn't have either backbones or hair? Out of curiousity, what does this have to BVZ's point? He said that a violation would require "No ancestor of [creature] to have [feature]". I feel you must have misread his post. quote:
If the platypus bill was too similar to the duckbill, they might attribute it to common ancestry (that at some time they acquired this bill through some common ancestor).However, it is similar enough for us to notice the similarities in shape (ie: we even call it the duckbill platypus and I gave many examples where people noticed that it is shaped like a duckbill. "The British scientists were at first convinced that the odd collection of physical attributes must have been a hoax." "It was thought that somebody had sewn a duck's beak onto the body of a beaver-like animal." Obviously, for it to have caused this much confusion suggests that there is a degree of similarity) yet different enough so that we won't attribute its similarities to a common ancestor. Ah, I see where we are getting confused. You think that the platypus bill can't be attributed to common ancestory because it's not similar enough. Wrong! The reason it can't be attributed to common ancestory because the platypus isn't decended from the dinosaurs, like birds are. If it was, it wouldn't have mammal features. Since it has mammal features we know it diverged after the point those features were evolved. But we also know it diverged before its reptilian features (egg laying, for one) were replaced. Its bill is a unique organ, which happens to vaguely resemble a birds bill. It can't be attributed to common ancestory because birds and platypus do not have a common ancestor with a bill. quote:
[the whole 'cousin brother thing'] Your examples, quite apart from being way too small scale to apply, and not dealing with the actual nested heirachy but instead dealing only with currently existing organisms, has one other major flaw. Evolution acts on populations, not individuals. The B1, B2 C1 example, for instance: To get it, you would have to do this: G1: GrandParent 1, with both genes Y and Z P1, P2: Parents 1 and 2, P1 must have both Y and Z, and P2 must have gene Y. B1,B2,C1: B1 has Y, B2 has Z, C1 has Y. Hence, you have B1 sharing a trait with C1 that B2 doesn't have. Now we'll apply that to populations: G1: GrandPopulation 1, with trait Y... Err... in humans you can have recessive genes which means that gene Z can be stored along with gene Y. Not possible in entire populations... and even if it was, how would B2 get trait Z back when its parent population had trait Y? Your analogies are useless. Sorry. You are still trying to say according to the theory evolution can 'undo' a trait (to take an example, a backbone) and go back to being invertebrate as easily as a human can go to an eye colour that its parents had. This is what we call a strawman. quote:
[the bats and horses issue] If horses shared features with cows that they didn't share with bats, and then the study found that bats are more closely related (PS: closely related refers to time-since-divergence) than cows, this would constitue a violation. However, what the study found was that a single branch of the tree, put there simply because there were no major features to go on at the time it was classified, was incorrectly placed. It wasn't a violation, merely a mistake. This needs a diagram, I can tell: OLD------NEW --|--------| -/|--------|\ /-|\-------|-\ |-|-\------|--|\ |-|--|-----|--|--\ |-|--|-----|--|--| B-H-C----C-H--B See? Nothing significant evolved between the bat divergence and the 'horse cow' divergence (on the old diagram), so there was no way to tell where to put the bats. The heirachy was updated when genetic information came to light. A Pegusus, or a bird mammal, on the other hand... they would very much violate the nested heirachy. One last thing: You seem to think that if one of these were found, scientists would still try to find a way to write it into evolutionary theory. I don't think that scientists are that idiotic. If one was found, they'd still try to find a natural explanation (because that's what science does... it takes the inexplicable, the supernatural, and explains it) but they wouldn't try to fit it into evolution.
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