Evolution Requires Reduction in Genetic Diversity

Of course not. But confirming it would. Though it's not exactly a "theory of evolution." Clearly said what, that this is MY theory? I would have thought that was pretty clear, but if it helps I'm glad if it is clearer now. Just curious: What did you THINK I was talking about?As for terminology, it is never easy to talk about phenomena from within a new explanatory framework when those phenomena already have terms attached to them from the framework you're trying to answer. You can't use NEW terminology or nobody will know you are talking about familiar things. I've worked on this a long time off and on, and done the best I can with the terminological problems. I nevertheless still sometimes forget to make a necessary distinction or I use a term in a sense that can be misconstrued. Just have to hope that over much repetition the basic idea will get across. I kind of think that was done with the cheetah, but never mind, that will take us too far off course and sure, the emphasis on a perfect specimen is a human concern. But when it was said that mutations always increase diversity as if that applied to domestic breeding as well, I had to answer that mutation would only interfere with the breeding objective -- and it doesn't, meaning it doesn't occur as you think it would. Even in the wild nature seems to do a pretty good job of maintaining its well delineated "species" without much interference from constantly occurring mutations.And I feel I need to say for the sake of terminological clarification that although I use the term "selection" a lot I usually use it in a much broader sense than "Natural Selection" and this is no doubt one of those places where the terminology can get confusing. By selection I mean ANY way a smaller gene pool is "selected" from a larger, or "isolated" and especially "reproductively isolated." Natural Selection is one of the ways that happens as some alleles are preferred to others and come to dominate the phenotype while the nonadaptive ones are reduced or even eliminated from the gene pool. But even in random "selection" of a smaller gene pool from a larger, as by migration and geogrphical isolation, the exact same processes occur: you get some alleles making up a new phenotype while others are left behind in the old population. In this case the "selection" is random but it works just the same way. Any "failure to remove new variations" is talking about failure to remove PHENOTYPES, but this is not GENETIC diversity you are talking about. This is the same mistake RAZD made and it is an easy one to make and I try to be alert to catch it when it happens. You are apparently talking about an increase in PHENOTYPES or VARIETIES, but my point is that when that occurs the alleles that don't support that particular phenotype are reduced or eliminated from the gene pool and that's a reduction in GENETIC diversity. This is ALWAYS the case. You ALWAYS get genetic reduction when you get new phenotypes.Again the "selection" I am talking about isn't natural selection, isn't necessarily focused on any particular variation but can be quite random and yet produce a new phenotype from a new isolated gene pool -- while reducing the genetic diversity of the gene pool. I've got plenty of those but they all amount to the same thing functionally: a new gene pool from an old with reduced numbers of individuals, reproductive isolation, perhaps other kind of "selection" as well including Natural Selection, but the reduction in numbers plus the reproductive isolation is quite sufficent for the purpose -- the purpose being the establishment of a new population with a new phenotype, which requires the reduction of GENETIC diversity within that population's gene pool.In answering your post my main objective is to try to clarify terminology, which you recognize is a problem. I hope I've been somewhat clearer here.Edited by Faith, : No reason given.

I sincerely doubt it. All it takes for a new phenotype to develop and come to characterize a new species is the isolation of a portion of a population so that it inbreeds among its own members apart from the original or parent population until its own set of alleles are thoroughly mixed in its own gene pool. That would take some number of generations, perhaps a few hundred years if we're talking about a population of cattle that reproduce every year, that started with say 100 individuals, but not more than that. If the new gene pool contains much fewer individuals it will take much less time. As long as reproductive isolation is maintained a new "species" ought to be fairly rapidly formed in any case. Not of wild species but perhaps of domestic species. Cattle breeds for instance. I think some have taken only a hundred or so years to develop.And if the same conditions are met in the wild, which they could be, since all it takes is the isolation of a small portion from the principla herd for enough time to mix its gene pool through all its members. the Wildebeest, or Gnu, describes two separate "species" -- the black and the blue, and it dates their divergence to a million years ago, which I find rather laughable knowing that breeds take a lot less time to develop. Because all that is needed is enough generations to work all the offspring of all the original individuals through the new gene pool. No, it isn't and this is another factor in this discussion that will have to get considered in some thoroughness eventually. Certainly you can have whole populations of creatures that are all phenotypically similar and the underlying genetic diversity can be anything from high to low in such populations. There will always be new traits, new variations showing up in the population but they don't really affect the overall character of the population unless they get isolated in small numbers and form a new population.When I'm talking about the reduction of genetic diversity I'm talking about the situation where "evolution" is actively occurring, where a reduced number is reproductively isolated and inbreeds for some number of generations to produce its own characteristics as a population. The actual genetic diversity may remain quite high in a given new population depending on how many members are involved and how high the original diversity was. It's only when the diversity is already quite low that you begin to get anything that could be described as genetically "impoverished" -- the point is that it will always be genetically reduced with respect to the original population. It could still remain quite high. But the process of developing a new phenotype WILL reduce it, whether it maintains a pretty high diversity or not.When you get out to "speciation" or the actual loss of ability to interbreed with former populations THEN you can talk genetic impoverishment and that IS the natural ultimate ending point of these processes if they continue that far.NEVERTHELESS even such genetically impoverished poulations may maintain a surprising amount of vitality such as the elphant seals thyat increased to great numbers after nearly being completely killed off, and even the cheetah, which does surprisingly well considering its genetic limitations.(Here I will insert the remark from my Creationist perspective that if death had never entered the Creation, which occurred at the Fall, then all lines of natural variation or breeding could safely proceed to the genetic condition of the cheetah and the elephant seal without endangering them. The original Creation I believe was meant to produce myriads upon myriads of beautiful variations on animals and plants. It still manages to do just that though only to a tiny degree of its original potential because now death endangers those that are genetically depleted.)Must end this post here. Perhaps will pick up the rest later.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

The alleles that bring about the different beak, if isolated and selected to characterize a new subpopulation ...
-- or if you think some other genetic condition than alleles for the trait are responsible, then put it this way: the genetic condition that gbrings about the different beak, if isolated and selected so that it proliferates and comes to characterize a new subpopulation ...
will of necessity DISPLACE all the other genetic conditions for other kinds of beaks. Those conditions will be left behind in the previous population or die out or one way or the other reduced or eliminated. THIS IS WHAT I MEAN BY REDUCED GENETIC DIVERSITY.You do not get new features characterizing a whole population or "species" or "subspecies" without eliminating all the competitors. If this beak is to be established as a trait of its own species all the others have to get lost from the gene pool. That's genetic reduction.Where a feature is clearly determined by a particular allele or set of alleles it's probably clearer but I think the same principle applies. It actually wouldn't. Not sure why you think it would. It comes about merely by the mixing of existing alleles, nothing new is added. If it's brought about by a mutation, if that's what you are thinking of, that's still just an allele that has been changed by the mutation, nothing has been added, there is no increase in the genotype just a variation on that particular gene, which is the same thing a pre-existing allele is too. And the mutation still has to be selected for it to become a trait in a new "species" or population and that means the elimination of all the competitors which is the reduction in genetic diversity I'm talking about. Well, no, it doesn't increase the GENETIC variation, it only increases the SPECIES or PHENOTYPIC variation. Oh nonsense. Read through this thread to find out what I think. The problem is that it isn't easy to think this through and keep all the levels in their proper place. It wasn't easy for me when I first started thinking through all this either, so i expect others not to have an easy time with it.But do at least make an effort rather than assuming the usual. Edited by Faith, : No reason given.

I'm answer this post out of all the others attacking my argument because it's the most absurdly far from understanding anything I've said on this thread. All of them look like straw man arguments but this one looks like the strawiest of them all. Well you are certainly off to a bad start here. In most of the scenarios I mention I'm not even talking about selection in the sense of Natural Selection but I gather you didn't bother to read enough to find that out. And in most of the scenarios it's quite a benign situation of alleles / individuals being left behind in the original population as the new population randomly forms, in which new phenotypes emerge from the new gene frequencies. "Removes diversity overall?" Where are you getting that? I'm talking about how diversity is REDUCED (sometimes eliminated but ALWAYS reduced) by the fact that alleles that don't contribute to the new phenotype simply are not present in that gene pool or the phenotype would not develop. Usually there's nothing active about their removal, they are just left behind in the original population as the new one forms. I consider Natural Selection to be a rare occurrence, and that new varieties form normally from accidental factors, such as migration away from the main population. Not genetically it isn't. Whether the original population goes extinct or not is utterly beside the point but just for the record nowhere in my discussion has any population gone extinct. The phenotypes of the new "species" can only form because the alleles for old phenotypes are not present to interfere, and it doesn't matter if the new phenotype includes the mutation or excludes it, the overall effect of its formation requires that competing alleles be removed from the gene pool, and again, that's reduced genetic diversity. And here I'm trying to hard to keep my terminology simply and uniform and you still can't get it. Well, I knew it wouldn't be easy but I did think people here were better readers than you turn out to be. "Diversity" isn't what I'm talking about, I'm talking about GENETIC diversity. I suspect that as with at least three others here you are confusing the diversity of phenotypes with GENETIC diversity. If you are talking about INDIVIDUALS that is certainly what you have in mind. GENETIC diversity is NOT the same as phenotypic diversity and I've been very very careful with my terminology on this point. Since you aren't talking about any assumption of MINE the number of things wrong with it are wrong in YOUR thinking.I don't think you have a clue how I've been using the term "selection" either, not having bothered to read the thread where I've been at pains to discuss its use many times.I've said nothing about "causing the original species to die off." Where on earth are you getting this stuff? Traits are removed FROM A POPULATION by simply being LEFT BEHIND in the parent population. Uh could be. The genetic diversity of the original population which could include all those relatives is not at all affected by the situation in the new population where the genetic diversity is being reduced by the formation of NEW phenotypes. All the original genetic diversity could even be contained in a full collection of all the daughter populations put together as I suggested concerning the finch varieties on Coyote's chart. Even all the ring species separate populations put together. IT's possible for that to be the case while each individual "species" or population has reduced genetic diversity WITH RESPECT to the other populations that preceded it. "COUPLE THAT WITH?" NN, you do not have Clue ONE about what I'm talking about here. All the populations should vary from one another in their own unique ways. What ARE you thinking? How much of this thread did you read? Did you stop and think AT ALL? I know this isn't an easy argument to follow, it takes a little work, but I did myself do a lot of the work of keeping the terminology as accessible as possible. Sheesh. Again you are hallucinating something about species "dying out" that has absollutely nothing to do with anything I've said. Again I think your problem is at least partly confusing the phenotype with the genotype. I The loss of GENETIC diversity, get that, [size=5]GENETIC All of the original traits still exist in either the new variant or the cousins and parents of the species in question. [/qs]If the divergence isn't drastic the same alleles and their traits may all be present in the new population but in new frequencies, but if the divergence is greater then some alleles will most likely not be present at all. But the point I'm making is that this is a TREND, and that over many population splits the trend to reduced genetic diversity will show up most dramatically though in the first population splits it won't be as dramatic. But in order to get this argument you have to get at least a minimum of what I'm saying and you've missed the whole ballpark. I never said it did. But the speciated species itself will certainly have lost a ton of alleles for characteristics it does not possess while it retains only those alleles that support its own traits. Most of those alleles will still exist in the previous populations, they are only LOST to the speciated species. Hardly. If I could banish everybody from this thread who doesn't even get the first thing about what I'm arguing I would do it in a flash, and you'd be the first to go. Yes, I've noticed it. A very handy little item. Oh I've improved my argument since then, and extended it into new areas, not that you'd have any way of judging.Also my own contribution to that thread stopped far far short of that 670, after which the thread devolved into pure destructive idiocy.

So what? Edited by Faith, : No reason given.

This thread has gone to the dogs in the last few hours and I'm too annoyed to bother dealing with it now. Maybe later if there's anything worth trying to deal with. You guys don't seem to recognize you are just proliferating straw man arguments and raising objections I've already answered and I have to leave to get my blood pressure down in any case.

No, I don't believe that, it's just that I can't get the entire picture described in a brief post and i expect such questions to come up later. Unfortunately they come up later as accusations that I never thought of them. If people would DISCUSS instead of barraging, attacking, accusing and ridiculing such facts would eventually get discussed.The idea is that the other beak is in the gene pool but less and less expressed as the chosen beak dominates -- I do keep saying the genetic diversity is "reduced," it's rare that an allele is completely eliminated but it does happen with sharply reduced numbers and also at the far reaches of the process I'm describing. The emphasis is on REDUCED to that point.

The gene pool contains all the alleles for all the variations, no increase is needed. If you want to think they were created by mutations, I'll tolerate that idea up to a point, but it would be silly to think a brand new mutation is always going to be selected as the basis of a new phenotype when the gene pool is full of alleles for all kinds of variations anyway.When a new smaller population splits off the idea is that it contains a different mix of alleles than the mother population had and those that dominate in the new will be different than those in the old and that's what brings about a new phenotype. The alleles for the same genes that make up that phenotype that are not used in that phenotype are fewer in number and could eventually be eliminated from the gene pool altogether. The alleles already exist, Taq, whether they were created by mutation or built in at the beginning. You've got a ton of genetic diversity in the collection of alleles in the gene pool. Why are you guys always assuming you need new ones? If you're right and mutation is the source of alleles, then I guess you'll get some new ones but there's no guarantee the newer mutations will be selected anyway, why should they be? As to new alleles being increased diversity, yeah in a way, but again all a mutation can do is vary whatever the gene it affects does, which there are probably alleles in the population already doing, and when a new phenotype gets selected they're treated like any allele anyway, they either become part of the phenotype or they are suppressed or eliminated Sure. But I have no doubt there are already Bs and Cs and all the rest in the gene pool to begin with. Edited by Faith, : No reason given.

If it does, it's replacing another allele for beak type anyway you know, and surely all the possible beak types are already present in the gene pool so this "increase in diversity" is redundant and as I keep pointing out, once it gets selected the genetic diversity starts getting reduced anyway so it really amounts to nothing new in the end.

I'm aware of the problem you bring up and don't know how to solve it yet but yes it is possible some kind of mutation makes up the greater number of alleles than the gene locus allows.

If the diversity increases to any great extent you are going to lose your variety or breed. Where's the evidence that it increases to such an extent? Breeders aren't always having to contend with new traits after a breed is established. New traits do appear in individuals in the wild in large populations but they don't do anything to change the basic phenotype unless selected, and they don't have to be mutations either, they may be just the result of combinations of preexisting alleles brought about by the usual processes of sexual recombination. But even if they are mutations they still have to be selected to make a difference and when alleles are selected others are reduced and for a phenotype to become fixed as at speciationj they have to be eliminated altogehter.

The variation is BUILT IN to the genome it does not need to be ADDED.

I don't know about scientists but I certainly know more than YOU with your ridiculous misrepresentation of my argument.

Wow, you guys object to the idea that God created anything but you seem to think a mutation occurred precisely for the purpose of protecting a mouse from a recent lava flow? Aren't mutations supposed to be RANDOM? But you think this one just handily showed up when needed? What IS the evidence for that? I cant read the whole article right now but skimmed the first part and don't see how it's so certain that a mutation was involved. Again this sounds awfully teleological. What would cause the mutation to appear with such uncanny timing? Why isn't it a random event as I thought mutations usually are? And again how exactly do you KNOW this was a recent mutation anyway?Why couldn't it be a regularly occuring recessive allele in the gene pool that got selected because the light mice now get decimated by predators? They eat some light mice, the survivors continue to reproduce but now the recessives pair up more predictably, bringing out the darker fur here and there, they get selected because it's only the light mice that continue to get eaten and so on and so forth. which would also be the case if the dark allele were a regularly occurring but recessive variation. You know this absolutely for sure? Again how do you explain such a miraculously fortuitous occurrence according to the principle of randomness I thought was standard? That part is easy to understand, that would also be the case if the allele were ancestral. It's the part about the dark fur just showing up like the cavalry when needed that's hard to fathom.Dunno, the whole thing's a great mystery to me as you present it, redolent of miracle and magic.If mutations are now understood to show up on cue when needed it sounds to me like a whole new theory is needed here.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

But surely you know we have no problem with mutations causing DISEASES, Taq. It's the idea that they ever do anything beneficial that's at issue.