Extent of Mutational Capability

Well, yes and no.Consider first of all the sorts of mutations we know can occur.: substitutions, insertions, deletions, repetitions, etc. It is trivially true that enough of those would get you from (for example) the genome of a fish to that of an anteater, just for the same reason that if you changed enough words you could turn War And Peace into A Tale Of Two Cities. If we just thought about what mutations can do, that would answer the question. But in order for that to happen in the real world, each step has to be small, and each of the intermediate creatures has to be viable. Indeed, so as not to be removed by natural selection, the intermediates should be better, or at least no worse, than those forms that preceded them. So natural selection does impose limits on what mutation can achieve.It would, I think, be hard to work out what those limits are just sitting in an armchair, but we don't have to be theoretical about this. If we look in the fossil record at (for example) the evolution of modern birds from dinosaurs, we can see a whole set of intermediate forms from small dinosaurs up to modern birds all of which look like plausible steps; we can't see any reason why natural selection should have imposed a barrier against anything that has happened, though doubtless it has prevented a whole lot of stuff that hasn't.Edited by Dr Adequate, : No reason given.

He was asking questions, there's nothing there that needs defending.

Gene duplication has certainly been observed (see for example, Brown, Todd and Rosenweig, Multiple Duplications of Yeast Hexose Transport Genes in Response to Selection in a Glucose-Limited Environment); I do not know what you mean by gene "merging" or "conversion".

True; but vacuous unless you can point to any instance in which this would have been necessary to produce such evolution as is actually evidenced. Define "kind", please?

Oh, you mean fusion of chromosomes. That also has been observed.Ask a Geneticist | The Tech InteractivePerhaps in future you should not go about saying that things haven't been observed just because you haven't heard of it. At least do a little research first, instead of presuming that your own personal ignorance constitutes a form of knowledge. No, as a matter of fact, because scientists do not know what you mean by "kinds". Do you?

Operationally, a "kind" is a group of animals that a creationist will admit are related to one another and which is not a proper subset of a larger such group.(Obviously the meaning of "kind" therefore depends on which creationist one is talking to and what his opinions are on that particular day.)Edited by Dr Adequate, : No reason given.

I note that it is perfectly possible for CRR to be wrong about genetics without having an operational definition of "kind", so perhaps he should just stick to that.

Well, this is an interesting question, but the fact is we don't know. For example, we can measure the genetic distance between two groups (let's say chimps and humans). But all biologists acknowledge that a huge majority of the differences are neutral mutations that really make no difference, and that their accumulation means nothing except that a lot of time has passed since chimps and humans diverged from our common ancestor.So then you would naturally ask: but how many mutations are not neutral, and account for the stuff that makes us special --- our bipedalism, large brains, ability to use true language?And no-one has the faintest idea. We simply don't understand what all the stuff in the genome is doing well enough to estimate that figure confidently. I would guess somewhere between 1,000 and 10,000 mutations would account for it, but what do I know? (If it turned out to be 1,000,000, then I would think that the theory of evolution was in trouble.)And, of course, it's even worse trying to figure this out with your hypothetical future scenarios. There's no way we can look at the hypothetical genome of future cave-humans and figure out how many hypothetical mutations it would take to produce an organism that doesn't even exist, based only on your description of its phenotype. It may well be that sometime in our lifetimes scientists will be able to answer the first question, about the past, but I think we will be long dead and buried before we can answer your question about hypothetical future evolution.Edited by Dr Adequate, : No reason given.

Now, given my previous post you may wonder how we are so sure that (to continue with my example) evolution from more basal apes to humans did take place. Well, we can look at the fossil record, and we can see lots of intermediate forms. And (see my first post on this thread) we can see that in no case in the transition can we say that mutation can't have achieved that (because, as I pointed out in my first post, mutation as such can do anything); nor can we say that natural selection would have prevented the transition, because all the intermediate forms look very plausible as intermediate forms.So while it is theoretically possible that one day we might acquire such a profound knowledge of genetics that we will be able to say: "What appears to have happened, based on molecular phylogeny and the fossil record, nonetheless can't have happened", this seems very unlikely. In our present state of ignorance the burden of proof would lie on the person who claims that.

Quite so. And one should emphasize that not only does that mean that humans are closer to chimps than they are to anything else (after all, we have to be closest to something) but also chimps are closer to humans than anything else (e.g. gorillas).

It's true that we don't have to be closest to one species, but we do have to be closest to something, be it a genus, a family, or whatever. (Aren't chimps in fact a genus, what with the bonobos?)So you kind of miss my point, which is that the theory of evolution implies that because of the branching nature of evolution, such relationships should be reciprocal. If we are significantly closer to chimps than we are to anything else, then the chimps should be significantly closer to us than to anything else.It's true that we can imagine a phylogeny where the split between humans and the other apes was the oldest and deepest, and we would be equally close to all of them, but given that we have closest relatives in the chimps, we must also be the chimps' closest relatives: and that is a special prediction of the theory of evolution.

And bonobos. And the thing we are closest to is the genus Pan, not one particular species in it.

Formally: for any living organisms belonging to a clade X there will be a smallest distance to living organisms outside of that clade. Those living organisms which are (approximately, not to the very last base of DNA) that distance from X will also constitute all the living members of a clade (prediction #1) which we may call the "sister clade" of X. Then (prediction #2) the relationship of being a sister clade will be symmetric: if Y is the sister clade of X then X is the sister clade of Y.(So for example Pan troglodytes is the sister clade of Pan paniscus, and vice versa; but Homo sapiens is the sister clade of the genus Pan and vice versa.)Now, there's no reason why this should be so if not for evolution, and it seems to me that it is this sort of relationship that makes molecular phylogeny really convincing. If (for example) you tell a creationist that birds are closer to crocodilians than to anything else, then he might with some justice reply that they have to be closer to something than anything else. But if you add that also crocodilians are closer to birds than they are to anything else, closer than they are to lizards or Komodo dragons or what-have-you, then this is a rather more remarkable fact and harder to shrug off.Edited by Dr Adequate, : No reason given.Edited by Dr Adequate, : No reason given.

I specifically said "living organisms".Of course, it would indeed also be true if I'd said all species living or dead, but that wouldn't be testable, so it wouldn't be a testable prediction of the theory of evolution.

I should like you to expand on this fantasy a little further. Are you suggesting that there is some mechanism other than random mutation that produces the adaptations necessary for bacteria to digest 6-aminohexanoate linear dimer and other such products of nylon manufacture? If so, do you have a shred of evidence for this speculation? If not, what do you mean? Please attach meaning to this vacuous phrase by telling us how you measure how high up a hill a sequence of information is. Math fail. And yes, it's that classic creationist trope, the Non-Quanititative Quantitative Argument. A number is asserted to be too big or too small for evolution to have occurred without the faintest effort at calculating the number. Neutral steps happen all the time. Are you trying to commit the Texas Sharpshooter Fallacy here, or what are you trying to be wrong about?