Peter & Rosemary Grant, Darwin's Finches and Evolution

Faith, the problem is that you don't understand the main objection to your argument, and blaming other people for imaginary failings is neither polite nor honest nor productive.You insist that there must be a long-term continuing decline in genetic diversity. But that is just an assumption - there's nothing in your argument that demands it.We object that even if there are short-term declines in the long term genetic variability should remain stable.Our view is supported directly by present-day genetic variation and indirectly by the evidence for evolution. Your view has no such support.And that is why we don't accept your argument. Evidence trumps assumption. It really is that simple.

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It is a simple FACT that ought to be clear to anyone willing to think about it, that you HAVE to get reduced genetic diversity in order to get a new subspecies.

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As I said, you don't understand the objections against your argument.Although talking about subspecies doesn't help you. (Even if the subspecies has a lower genetic diversity than the rest of the species, it's still part of the species). I understand that you don't want to admit that speciation happens but you're cutting off your nose to spite your face here.

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This is NOT easy to grasp, it takes some thought but it IS simple and it IS factual. Your objections are not apropos.

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It seems that I understand it better than you - or you'd see the problem in talking about subspecies rather than new species. And I also understand that the continuous decline in genetic variation is the intended conclusion of the argument - or it would be no good to you at all. And my objections are very relevant to THAT. Which is probably the reaosn why you avoid talking about that issue all together.

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It would if mutation had anything to do with creating viable alleles but even you all acknowledge that the vast majority are either neutral or deleterious.

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Neutral mutations - by definition - must produce alleles just as functional (at least in the sense of fitness) as the pre-mutation version. Deleterious mutations often produce alleles that are still functional. Moreover the judgement of "neutral" and "deleterious" is relevant to an environment and can change if the environment changes. Equating "less helpful in the current environment" (deleterious) to "non-functional" is just wrong.More importantly there is no theoretical reason why there should be a problem. Our knowledge of how mutations occur does not point to the existence of any mechanism that would prevent useful mutations from occurring. So, that observation is not very helpful to your argument at all.In fact your argument relies heavily on the difficulty of making the observations that you personally require, not on anything that makes a real case against the theory. If you held that to be the basis of personal skepticism then it would still be a little unreasonable, I think, but that is your right. To try to make an argument of it, to say that other people should be convinced by it, is on the other hand completely unreasonable. A demand that other people should share your prejudice is not an argument.

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think you extrapolate this from the observed fact of new mutations occurring from generation to generation, plus the theory that requires you to believe that they are the source of functioning alleles, although this is belied by their generally nonbeneficial nature. Unfortunately the result of the accumulation of these different mutations in any population is ultimately most likely genetic disease, not the emergence of new healthy phenotypes.

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Of course there is nothing really unhealthy about neutral mutations (the majority) and even deleterious mutations can become beneficial or form the basis for future beneficial changes. And then there is the existence of beneficial mutations and the role of natural selection to consider. Considering the other evidence for evolution, at best you would have a weak case for an unknown source of beneficial genetic changes - and that would clearly fit the evidence better than your own views. And that is hardly what you want. (Michael Behe would be happy - but even he doesn't go that far. And he can't find the evidence he needs to support his own arguments).

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Again, the observed divergence between populations needs no other source than the change in gene/allele frequencies that is the natural result of the splitting of the populations itself. The best you can say for mutations is that the built in alleles wre originally the result of mutations, because the new mutations would not be of any use in bringing about this divergence, since they would have to be passed on in the population, which is not too likelyl to happen to any given mutations in individuals.

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This argument is just confused. Even if we accept that a particular mutation is unlikely to be passed on it does not follow that it is unlikely that any mutations are passed on. And natural selection will skew the odds away from deleterious mutations and towards beneficial mutations. Moreover, the observed genetic diversity requires additional alleles to enter the population whether using your YEC ideas of the history of life, or those of mainstream science. You have no observations which give us any positive reason to believe otherwise. So again it is seen that you are relying on assumption, against the evidence.

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In other words it's a good thing they can change the order of the DNA sequence and not do any real damage. Basically good design I'd say, that can survive such assaults on its integrity to the extent you all say occurs. A few more assaults on that same sequence might produce a different outcome though.

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It'd be a better design still, to reduce the number of "assaults" - if your views were correct.

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All assumption, all theory, all Creed.

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All pretty obvious facts.

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No "mechanism that would prevent useful mutations from occurring?" Pretty hypothetical statement that.

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My actual statement wasn't hypothetical at all. It's a fact that there's no sign of any mechanism that would prevent beneficial mutations from occurring

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I'd suggest the improbability of it for one thing, given the fact that mutations are a basically destructive occurrence, interfering with the normal functioning of DNA. For another, the extreme rarity of such an occurrence, and in fact the iffiness of the evidence when you are able to trace it at all. Meanwhile there are those thousands upon thousands of known genetic diseases.

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The probability isn't a mechanism and the alleged rarity is an implicit admission that beneficial mutations do occur (although they are frequent enough in bacteria that we can get them to occur in laboratory experiments). The "iffiness" of the evidence is due to our inability to collect the evidence you want - which just means we don't have the evidence to decide either way (at least not by direct means).

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The difficulty of making the observations that I require? You mean because I said it takes thought, it's not all that easy to grasp? That's somehow a proof that it can't be a real case against the theory? This is strange logic indeed.

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Which should tip you off that you are badly wrong. If indeed the difference between making observations and thinking somehow escaped you. Fir the record I was referring to your general refusal to accept that mutations have occurred unless given proof (which is rarely available), not agreeing with your attempts to cover up your lack of an argument.

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Then it sure is fortunate that I have made no such "demand," isn't it?

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Unfortunately you did exactly what I said. And in fact you did it again when you talked about the "iffiness" of the evidence for mutations. Again, the evidence is not "iffy" in any way that suggests that beneficial mutations are rarer than we think.

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More theory, creed, assumption.

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More facts you don't like.

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But again this is just based on the theory, with such a minuscule bit of evidence for it that it hardly exists at all.

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Since this thread is supposedly about work demonstrating natural selection (despite this derailment) that seems an unwise comment to make.

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What other evidence? You mean all those assumptions piled on assumptions? Don't know what you mean here.

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I am so sorry but rectifying your gross ignorance would take way too long and go much too far off topic, Go and read an introductory book on evolution. Then move on to a decent undergraduate text. That should do the trick. Well, it would if you were capable of dealing with them in an honest and open-minded fashion, but I think we all now that that is too much to hope for.

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I'm sorry, you've completely lost me. "Unknown source of beneficial genetic changes?" But of course I'm claiming that all beneficial genetic changes -- if we're talking about observable change from population to population at least -- that are known to occur are explained by the processes I'm laying out here. Nothing unknown about it.

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Well that's odd because you seem to be denying any such process. What is the source of new beneficial variations in your view ? It doesn't seem to be mutation but I haven't seen any other.

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--although I wouldn't put the word "beneficial" in there because that's an artifact of the ToE and has nothing to do with what really happens in reality, which is that change occurs with the shuffling of gene/allele frequencies and in most cases the change is just as viable as the original population, no better, no worse.

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Well that's just babbling nonsense.

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Well you really HAVE lost me, I have NO idea what you are talking about now.

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Michael Behe, famous ID supporter and former creationist now argues that evolution is mostly true but that God occasionally steps in to give it a helping hand, by causing an extra mutation or too. Except he's still looking for a real case where that would be necessary. So I guess that you ought to ask yourself why someone, someone who had the full support of the ID movement would go so far in embracing evolution (to an extent that many in the ID movement would NOT accept at all), unless he was convinced that the evidence pointed that way ?

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Seems to me it is VERY unlikely that any single mutations, that is, mutations possessed by single individuals, WOULD be passed on at all.

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Can you explain your reasoning ? It seems pretty likely to make it into the next generation, at least. And again, the probability that some will be passed on is very different from the probability that a particular one will be passed on.

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But anyway, again, this is pure assumption, that mutations have anything at all to do with the formation of species/subspecies, and that natural selection is always the reliable hero ready to save the day when things go a bit wrong. The ToE says it's so, therefore it is so.

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Funny that you are attacking things I didn't even say.

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WHAT "observed genetic diversity?" This is FICTION, PaulK. You say it is "observed," where is the evidence?

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I was thinking of the human genes in the Human leukocyte antigen genes, some of which have hundreds of alleles, as an example. Fact, not "FICTION"

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Getting anyone who is steeped in the ToE to see anything I have to say is not something I have any illusions about any more. The argument has been sufficient but the eyes are closed.

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And that's an outright lie. In reality your argument stops before getting to the crucial point, which is and always has been an unsupported assumption.You've made various attempts to support it, for instance insisting that mutations don't happen or asserting that new variations would interfere with evolution in some way you could never explain, but it is quite obvious that those are inadequate. Now you just try to pretend that you have an argument but never try to explain it.

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What's really odd here is that you all keep complaining I'm ignoring the evidence but what I've been getting from you is mostly theory and assumption, no evidence at all.

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Not really, when it is considered that the evidence has already been discussed, this whole conversation is off the main topic of the thread and there is always time to go into more detail if it is needed.On the other hand it really is odd that you tell people that they will find that your argument is correct if they only think - when it obviously hasn't worked for you.

The evolution of birds shows some problems with your argument, Faith.Some traits aren't fixed. Size is the easy example. While a species has a relatively narrow range of size, the difference between a wren and an ostrich is huge. And there have been birds bigger, still.Some traits open up a range of new possibilities. You can't have plumage patterns without plumage, there,s a huge range of shapes and colours and patterns. And the range of bill sizes and shapes is dependent on having a bill. Again, lots of new diversity.And traits can be lost. A number of different lineages have lost the ability to fly. Penguins are adapted for swimming, ostriches and similar birds are too large for efficient muscle-powered flight.There's no continuous narrowing down of traits, new variation is always coming in.I know that you don't believe all this, but that isn't an argument. Nor is assuming that it couldn't happen. You need reasons why it can't. And we've been waiting for you to supply those for years.

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Leaving aside whether this really occurs, this is not evolution/microevolution. I'm only talking about what brings about microevolution

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But it is. More to the point even if it wasn't it is highly relevant to your argument. What you're really saying is that you are only interested in the loss of genetic diversity, so you can ignore gains. But that doesn't make an argument that loss must outweigh gains, it's just a refusal to even consider gain.In short, you are choosing to blind yourself - and then accusing others of blindness for not doing the same.

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I do think that anyone who thinks THROUGH what I'm saying should come to see it as I do.

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So far, everybody who has thought through it has disagreed.

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What happens to the genetic increases is hard to describe clearly. I might be able to illustrate it but I don't think that would be particularly clear either. But let me try to describe what I'm seeing.

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I think that the real problem is that you have no clear idea yourself. Certainly making excuses for ignoring the increases in diversity suggests a lack of any real argument.

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So what is happening in this population? Genetic changes are occurring from time to time. You attribute these to mutations, I attribute them to simple sexual recombination of existing alleles. Of course I'm sure you include this in your scenario too, we are merely disagreeing about the source of the genetic material.

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Even if you're referring to phenotypic changes we know of examples due to mutations, so your insistence here is against the facts.

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So these genetic changes are occurring. Say they ARE mutations in single individuals. How many of these occur in the germ cells? Anyway it's only those that will get passed on of course. And only the neutral and the "beneficial" ones if we assume the bad ones will be selected out. And as you've all pretty much agreed, this can take a very long time. If mutations could save the cheetah it will be a very long time if they can hold out that long. Anyway...

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In all the discussions we've only been counting the mutations in the germ cells, so your first sentence suggests another failure to understand. Anyway, the cheetahs are such an extreme case that it's surprising that they're still around. But they are, despite human hunting inflicting another bottleneck on their population.

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So after a generation or two the genetic changes start to show up in the phenotype as the offspring and the offspring's offspring mate together. Or maybe even in the first generation if the genetic change is dominant.

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OK so far? What would you correct?

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On top of the points that I've already made, selection is based on the trait, so that won't happen until the trait starts showing up in the populaton, so the ordering of your discussion is a bit odd.

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If there is genetic drift that appreciably favors one or more of these new traits those will start appearing in the population in greater numbers. If the drift is very strong they night even come to characterize the population as a whole. I think the usual idea is that this should take a very long time. I tend to think in terms of a relatively small number of generations myself, fifty being a lot.

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Any problem with that?

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You seem to be confusing drift and selection. Selection works much faster than drift, because drift really is chance. And 50 generations is way too small. Even the rapid speciation proposed by Eldredge and Gould takes longer than that - and you should be thinking about the longer time between speciation events.

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OR, if a part of the population gets lost and ends up in a new part of the forest and sets up housekeeping there, no longer with any reproductive contact with the old population, and continues on there breeding only among themselves, growing their population and so on, what I'm saying is that whatever genetic material they brought with them in greater frequency than that expressed in the old population will now come to characterize this new population. Say longer tails, a white diamond-shaped splotch over the nose, a lavender tinge to the coat, and general shorter stature. All this built from the mutations that came with the individuals that formed the new population.

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There's likely to be a selective element, too, to fit local conditions.

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What I'm ALSO saying of course that in the development of this new species alleles for traits from the old species or any traits that are not those favored by greater frequency in the new population, will start to disappear from the population and if low frequency enough to begin with, may drop out altogether. At this point there is no new genetic input, there is only what was brought over from the old population, unfavored alleles are starting to disappear, which is the loss of genetic variability I'm talking about, and some of the high frequency alleles may soon be homozygous or fixed loci even through the entire population. (If enough of this happens for enough of the characteristic traits it seems to me that a genetic inability to breed with the former population could develop simply from this fact, but there can be many reasons for an inability to interbreed to develop between cousin populations of course).

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Of course this is largely repeating what you've already said. There isn't a lot of point in distinguishing between variations produced by mutations in the parent population and those that were inherited from earlier ancestors.I CAN say that it has to be difficult to get an inability to interbreed in that way, for the simple reason that fertility barriers within a species are an obvious disadvantage.

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If the original number of founders of the new population was quite small I would expect the change in allele frequencies to be dramatic enough to change the look of the new population rather rapidly, the unfavored alleles dropping out faster, and the inability to interbreed with the former population could develop very fast too, maybe even in a matter of a dozen generations or so, but give it fifty. It should show significantly decreased genetic variability from the former population by this point. The population should be sufficiently different from as well as unable to interbreed with the former population to earn it the label New Species.

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If the number of founders is too small they'll need favourable conditions or a lot of luck to survive. And I think that complete loss of interfertility will take longer than you believe. How long have lions and tigers been separated ?

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So back to the increase in diversity. Just go back to the original scenario. That increase has to be cut down IF the population is to evolve a new set of characteristics AS A POPULATION, and this is also what happens in genetic drift, it's simply another way this happens. Otherwise you'll have a nicely variegated population, perhaps millions of individuals with a very wide variety of traits among them.

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Which is why speciation rarely, if ever, occurs in large populations (and is slow to occur if it does). This is the reasoning behind Mayr's proposal that speciation was the result of a small sub-population becoming isolated from the main population. You,ve referred to a small number of founders yourself. So let's agree that speciation is difficult, given a large population.

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Now you seem to want to call THAT situation "evolution" too which of course only muddies up the point I'm trying to make.

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More correctly I want to call the appearance of new variations in a large population, as well as the changes in allele frequency due to drift and selection in that population, evolution. Although there probably won't be much drift or selection going on, proportional to the population size.

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Are you REALLY saying MACROevolution doesn't depend on the formation of distinctively new populations, but that the normal variation from generation to generation without there being any sort of isolation or selection acting on it, would ultimately lead to MACROEVOLUTION just as well as the formation of distinctly different whole populations would?

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Of course not. And I've explained this before. In my view the usual process of macroevolution follows the original Punctuated Equilibrium model. A small population gets isolated and rapidly (say in about 1000 years) becomes distinctive enough to become a new population that does not interbreed with the parent population even if they should meet together. That population is successful (no need to consider those that are not), spreads and becomes much larger. For a much longer time it is stable. Variation increases mainly during the period of growth (where it is most rapid) and the period of stability. From this population, in time one or more smaller us populations will split off and themselves become new species.That is not the only way it can happen, but I believe that it is the most common way.

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Now I can't see how. I can see how you get new species but that requires the reduction in genetic diversity no matter how much you increase that diversity here and there. If it isn't reduced you aren't going to get a distinct new species. And if you don't get a distinct new species but only a very variegated large population I don't see how you are getting the kind of microevolution that Darwin identified in his finches and turtles and so on, and of course since to get this distinctive new population requires loss of genetic diversity end of evolution.

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Of course, this is ignoring points I have already made in past discussion. The point is that the reduction is FOLLOWED by an increase, so we get a variegated large population that is still a distinct species.

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You've said I haven't sufficiently explained how the increases in genetic diversity don't answer my argument and I hope I've made it somewhat clearer.

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Since I can easily answer your argument by repeating points made in previous discussion it seems that you have not thought it through.

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I think YOU need to explain how you get new species without this reduction in genetic diversity. Of course you theoretically get new individual traits from the ongoing mutations, but unless they are selected or isolated so they can proliferate as a new population you aren't getting the kind of change that evolution is defined by.

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No, I don't. Because I am claiming that the vast majority of the new diversity is added after the speciation has occurred. And you haven't addressed that at all.

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But where have I said anything to imply it's fixed

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The point is that there are traits which are distinctive to a species, but not distinctive to all it's descendants. Thus, these traits never need "run out" of variation.

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AND remember I'm arguing from an assumption of separately created Kinds, so I don't necessarily assume a wren and an ostrich are genetically related. But if they happen to be, size is something I WOULD expect to vary dramatically in the original population from which they diverged.

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Your beliefs aren't really relevant, since they render the whole discussion moot. However, since even dogs vary less, at least proportionately, and that is the product of heavy selective breeding, it seems very doubtful that a single species could contain that degree if variation.

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Same answer as above. I'm assuming such a huge range of differences in plumage, bill size and shape and so on, it's the stuff from which microevolution is made, it's the stuff that makes the different birds in a ring species of birds. I don't believe that plumage or bills evolved from some other species of course, but even if they did it would be by the same methods I'm describing here.

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And that is an even worse failure. The point being made is that a new trait can open up a whole range of possible traits that couldn't,t be realised before. Nothing you say above answers that at all.

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And of course I've been talking about populations eliminating alleles haven't I? Alleles are the basis for traits, aren't they?

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And again, you miss the point. If a trait is lost the species need no longer maintain that trait, allowing diversity again.

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But focus on what happens when you have a new population based on a smallish number of founding individuals. Think about what the change in allele frequencies means. You are getting higher frequencies of some alleles for some versions of some traits than those in the original population, so you are getting new traits in the new population [[[ABE: I mean new traits in enough numbers to become CHARACTERISTIC of the new population /ABE] after some generations of inbreeding, and you are getting lower frequencies of the alleles for the different forms of those same traits in the old population and if low enough they drop out altogether. I wouldn't describe this as a "narrowing down of traits."

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If you are eliminating alleles for different traits, then of course you are narrowing down the traits present in the population. And, of course, as I,ve said before we need to consider the whole picture, not just a small part of it, even if that part is much more important than it's size suggests.

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And I've tried to explain in that last post how you simply would never get anything you could call a New Species IF new variation did keep coming in and changing the whole population. Of course you will get new traits continuing to pop up in INDIVIDUALS within the population assuming there are still alleles for those traits in the mix [[ABE forgot here you are assuming mutations instead, but that works too/ABE]=, but unless they change the character of the whole population you are not getting a new species.

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Yes, we know that adding variation to a species does not create a new species. But new traits appearing in individuals and NOT spreading to the entirity of the population IS exactly what an increase in variation IS. So really, you are objecting to increases in variation by saying that they are increases in variation.

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And at this point I've asked how you can have evolution if you are NOT getting new species. Which is something you are all claiming.

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Because new alleles in a population by definition change the allele frequency in that population. The frequency of that allele has increased from zero to one!

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I think I've done a lot more than assert my belief and assumption and hope that last post makes it even clearer. I've been giving reasons all along it seems to me.

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Since you seem to be repeating the same old errors over and over again and ignoring rebuttals I think it is quite clear that you don't have anything more than belief and assumption.

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Need to say more about "narrowing down of traits" which I didn't grasp at first. You say this isn't happening. But it has to happen in Natural Selection, for instance, where only the adaptive traits are preserved. The ones that didn't work for the environmental situation drop out, are maybe even killed off by a predator. That's a narrowing down of traits isn't it?

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The point is that the overall number of differing traits doesn't have to keep going down all the time. In fact we should expect it to hit a balance. Remember that I am not talking about the short term, like individual soeciation events, but the long term through a whole sequence of species.

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My first of the last three posts was to describe the accumulation of mutations in a basically static population, which makes for a variegated population that grows in numbers but doesn't evolve into a new species. You say I keep avoiding this, no I'm describing it and have been describing it all along. A static variegated populatuon is all you get with increases, you don't get new species. (Micro)evolving into a new (sub)species requires the selection and isolation processes which leads down the line to reduced genetic diversity.

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You've been ignoring the consequence of this, which is that the new species is formed from whittling down the diversity of the variegated population, not the less varied original population. Thus diversity should follow a cycle of reduction and increase, not a monotonic decrease as your argument requires.

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So you keep expanding and contracting down the line, you are not getting evolution

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You say that, but it's obviously untrue. We're getting a whole sequence of distinct species - probably with multiple branchings - how is that NOT evolution?

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Every time you have speciation you have something that interferes with it, and that presumably can keep on going indefinitely, there is no real speciation happening.

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What is this something? You've said it before but never pointed to a single thing. So far as I can see you've just pulled that claim out of nothing.

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Fitness as an adaptive mechanism is just an article of faith, in reality there is hardly any struggle in the Darwinian sense to adapt. Just another tenet of the theory assumed as fact without evidence. There are certainly some striking adaptations but they can just as easily be the right beak finding the right food as the available food determining the right beak.

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That's a very silly thing thing to say in this thread, of all threads. Unless you are accusing the Grants of fraud? If so we'll want rather more than your jaundiced opinion to back it up.

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As for what is macroevolution: I define it functionally as the point at which microevolution so decreases genetic diversity that no further evolution is possible.

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That would be extinction. Which is pretty useless as a definition of macroevolution.

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However, here's another attempt: It's whatever CAN vary in the given genome of the species, its peculiar traits and the genes for those traits with their various alleles. No variation is possible outside those built-in design limits.

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That doesn't even make sense as a definition of macroevolution.

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Your post didn't mention mutations so I didn't. That doesn't mean I ignore them, I've responded over and over to the claim that mutations add genetic diversity by assuming for the sake of argument that this occurs and answering accordingly...

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Which generally takes the from of finding excuses to ignore them.

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...and the conclusion I keep coming to and trying to demonstrate is that the inevitable trend even WITH mutations is to decrease in or loss of genetic diversity WHEREVER EVOLUTION IS ACTUALLY OCCURRING, evolution meaning selection and isolation processes that lead to the development of a new subspecies or even species, that is, the development of a population-wide divergence in phenotypic character from other populations of the same Species

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So you have to invent your own definition of evolution. However, redefining evolution to exclude increases in genetic diversity, doesn't change the fact that you still have to take them into account to have a valid argument. So, even if your definition were correct it's irrelevant. And that is why it is just an excuse. You aren't coming to a conclusion, you'r making excuses to keep to your desired conclusion.So we're back to the model where there are decreases in genetic diversity during the period of speciation, counterbalanced in successful species be increases in diversity during the period of growing and large populations.So far your only objection to that happening is that if that were the case something would prevent speciation. But I'm still waiting to find out what it could be. If your position is really the product of thought then why haven't you suggested anything that could do it ? Or even any idea of how it could do it ?

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Paul K said that narrowing of traits doesn't occur down the evolving pathway but of course it does, it has to. Any daughter population represents a selection of traits out of the greater population to become its own characteristic look over time.

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Let's make it absolutely clear. I do NOT argue that there are no periods when genetic diversity of a particular population decreases. I HAVE argued that successful species regain genetic diversity during their periods of expanding and large populations, so that for these species - and their successful descendants - genetic diversity follows a cyclical pattern of decrease and increase.And your current objections are that we should ignore the periods of increase because you don't count it as evolution - which is both false and fallacious - or that something would stop speciation in such cases without suggesting anything at all plausible that might do so.So where is your case ? An excuse for only looking at decreases and ignoring increases isn't a valid argument. Nor is the assertion that SOMETHING will somehow make things come out the way you want. But those are what you offer.And that is why anybody who THINKS about your argument will see that you don't really have one - just an assumption poorly hidden by excuses.Edited by PaulK, : Trivial corrections