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Thread: Further proof of Evolution? 4-finned dolphin....

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    Stay chooned in for more! Clint's Avatar
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    A dolphin was found with 4 fins. Scientist believe it could be ancestral dna.

    4-finned dolphin

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    War. War never changes. Est's Avatar
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    We have already observed vestigal bones in fins. In whales, which are presumed to have come from land animals, we can see the vetigal remnants of bones much like the structure of our hands. This is an interesting article, however. Thanks for posting.
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    The article says fossil evidence points to a common ancestor between porposises and deer, but I was previously under the impression that porposises were closer to the felines in descent. Anybody know which possibility has more clout?
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    Stay chooned in for more! Clint's Avatar
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    Hehe, I made sure to put a question mark in an attempt to not start a flame war. I learned that trick from CNN.

    I can hear it now..

    "CNN has a liberal bias and only tells half the story blah blah blah!!! "

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    This doesnt prove evolution, but it showes that theirs chance for mutation, theirs alot of gaps in Evolution, but theirs alot of gaps in every thing...

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    Stay chooned in for more! Clint's Avatar
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    Yeah yeah, I know. But it does help strengthen the theory.

    What they are saying isn't that this is a mutation. They are saying that fossils show dolphin/whale like animals with 4 fins, and this live animal shows that perhaps the dolphin could have evolved from them. I know they did because Evolution makes perfect sense to me.

    When I was a christian i thought that evolution was gods way of making everything and the genesis story was a metaphor.

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    Quote Originally Posted by [b
    Quote[/b] ]The article says fossil evidence points to a common ancestor between porposises and deer, but I was previously under the impression that porposises were closer to the felines in descent. Anybody know which possibility has more clout?
    Well...it's complicated. They did evolve from an ancient land carnivore, but not from a member of order Carnivora. Way back when, there was a group called the Mesonychids, which evolved from ungulates such as deer, but were carnivorous. Some were roughly wolf-sized, with more elongated skulls and cat-like tails, while the largest, Andrewsarchus, was significantly larger than a kodiak bear, with a skull well over 4 feet long.

    In recent decades, the fossil record of whale evolution has become much clearer, with literally dozens of steps between mesonychids and modern whales and dolphins being discovered. Wikipedia has a good layman's version, with more detail (but still at the public level) in Carl Zimmer's book At the Water's Edge. Whale evolution on wikipedia.

    The link between whales and mesonychids is pretty much solid at this point, though there's some quibbling about whether it might have been a poorly-know sister group to the mesonychids, IIRC. It wouldn't be paleontology without quibbling.

    Quote Originally Posted by [b
    Quote[/b] ]This doesnt prove evolution, but it showes that theirs chance for mutation, theirs alot of gaps in Evolution, but theirs alot of gaps in every thing...
    Nope, it doesn't; we've proven evolution long ago. This is just another drop in the ocean of evidence.

    Quote Originally Posted by [b
    Quote[/b] ]What they are saying isn't that this is a mutation. They are saying that fossils show dolphin/whale like animals with 4 fins, and this live animal shows that perhaps the dolphin could have evolved from them.
    Well, it's complicated (just about every answer in science involves that phrase).

    Genes don't just make structural protiens; they also control the expression of other genes, which may in turn control the expression of yet more genes, and so on and so forth. It is entirely possible to lose a structural trait, such as limbs, not by loss of the limb genes, but by the loss or change in activity of the genes that turned those genes on in the first place.

    What I suspect happened in this case is that this dolphin had a mutation to the genes which controled limb development, activating limb genes that had really been there the whole time but where never activated in other dolphins. This has happened multiple times in whales as well, and we recently managed to get chickens to grow teeth by the same mechanism: restoring the signal that activated the tooth genes hidden the whole time. In what should be totally unsurprising, the chicken teeth formed in a manner seen in only one other group: archosaurian reptiles (a group including modern crocs and the extinct dinosaurs).

    I'm really unsurprised, but I think it's *very* interesting for another reason: Gray's paradox. The first scientist to study animal locomotion, Gray found a simple scaling in how much drag fish are subjected to, but when he did experiments on a mock-porpoise, he got turbulent flow, massively increasing the drag. We know from data on how fast dolphins swim that they *must* have a method of laminarizing the flow around them, and this has been extensively studied. But here we have a dolphin with two protrustions that would *seriously* disrupt flow around the body. I want to see how fast this thing can swim, and what the flow looks like. It's possible that hind-limb loss in dolphins may be their solution to Gray's paradox, and that this individual can prove that by showing that limbed dolphins generate turbulence.

    Overall, though, it's not really surprising. These sorts of things are commonplace, just not in species that are cute and fuzzy and therefore get major media attention.

    On a similar note, horses born with 3 toes, like their ancestors, are actually also well known. It's said that Alexander the Great rode one, believing it to be good luck.

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    We have PROVEN evolution? How? When?

    Where was I? (don't say it!)

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