Evolving the Musculoskeletal System

How much adaptation do you believe in?Can you get a Polar Bear and a Grizzly Bear from a common ancestral group? (The differences are adaptions).If so, can you get all bears from a common ancestral group?If not, why not? It's just adaptation.On skeletons: There are examples of mutations in modern human bones that could conceivably be advantageous in certain circumstances.Some of the rarer forms of Polydactyly is one. It's common for people to be born with extra digits on their hands and toes (about 1/500 of the population), but most are useless.However, some do produce functional new digits that are actually separate from the others. Because we have well shaped hands, and already have the optimum number of digits, these extras would not be advantageous in our present circumstances.However, if that weren't the case, these rare forms of polydactyly illustrate how mutation can be creative in the kind of dramatic way you seem to be looking for.Another is single mutations that can both decrease and increase bone density all over the body. Again, we probably have about the right optimum, because we don't break our bones often enough for the increased density (stronger, heavier bones) to be particularly advantageous. But some people do have them, and you can see the potential flexibility which would be available for selection were we living close to nature and under pressure.Perhaps more common than dramatic changes like increasing a digit are exaptations of existing bones for new purposes, like the Panda's "thumb", a sesamoid bone put to new use.Edited by bluegenes, : spellingEdited by bluegenes, : No reason given.

Sure, hence my point about the Panda's "thumb", above.However, the creationists on the thread are asking for dramatic novelty from mutations, and the rare functional extra digits show that it's possible. The thread starts off with someone listing the number of bones in our body, as if the implication is that mutations can never create extras, so I point out that it can, and still does.Much better for Bolder Dash is my question about bears. If he believes in adaptation, where does he put the limit on adaptation? How many adaptations is a population group allowed to make over time?Edited by bluegenes, : No reason given.

So, let's see if we can find out where this line is.Do you think that it's possible to get a Grizzly Bear and a Polar bear from a common ancestor? (There are "musculoskeletal" differences between them, although they're minor, relatively speaking).If not, why not?If so, then could you get all bears from a common ancestral bear? (More differences here, but not dramatic ones).If not, why not?We could start from there, and see what changes in animals you think could happen naturally.It's worth considering that Polars and Grizzlies can produce hybrid offspring.

In a way. Why not give IC a seagull example, or another of your choice, and we can work on that as well.But bears are good, because they're big and easy to look at and visualise, and there are some interesting skeletal differences between the two bears I mentioned.

You won't be able to breed a lion with a cheetah, either.But at least you agree that all the changes in muscle and skeleton that we see in the cat family can evolve naturally. That's progress.So why can't all the Carnivora descend from a common ancestor in the same way? Apply some common sense, and you'll realise it's possible.Edited by bluegenes, : punctuation

To say fair, Koonin does point out that there could well be far more probable ways in which life could arise. Indeed, as I read it, he's just saying that we haven't yet worked them out.He does overstate his case, arguably, but that's because he's trying to make the point that, even if you took one of the apparently extremely improbable examples of how life could have arisen naturally in a finite universe, in the currently popular "many world's" scenario, even that way of life originating is inevitably going to happen.His argument implies that, if the many world's hypothesis is correct, the intelligent design folk can forget their intelligent designer as being necessary for any observed phenomena in our known sector of the universe, so long as it doesn't break any physical laws, no matter how unlikely it may seem.Interestingly, this would mean that if life arose here by some unknown but much more probable process (in the many worlds scenario, that would just mean more common), it would still have arisen elsewhere by the process he describes, as well as arising elsewhere by the same means as here, and by any other possible means.So, he's not saying that his apparently highly improbable way of life arising is the only way, but that if it were, life is still inevitable under the many worlds hypothesis.The most interesting thing to me about the paper is not about OOL, particularly, but about how we would approach probabilities in a "many worlds" cosmology.I don't think your bullshit alarm is necessary, as the paper is very, very pro naturalistic OOL in its implications, and Koonin's certainly not claiming that there aren't more probable ways than his for life to arise. If ICDesign was capable of understanding it, he wouldn't have brought it up, but he did so because Koonin is being quotemined by creationists elsewhere (something one of the papers reviewers predicted, to my amusement!).As for the calculations in the appendix, he describes these as "naive" earlier in the paper.{I know this post is off topic, but I thought the paper was interesting, even if slightly flakey. If ICDesign expresses incredulity about any detail in the evolution of the skeleton, and you're getting pissed off, you can always say to him that, according to his friend Koonin, if it's physically possible, it's inevitable that it would have happened in one of the many worlds. }