Evolution Requires Reduction in Genetic Diversity

I think this is the strongtest statement yet of what you're really saying, but it still contains a bit of inconsistency because it begins by describing how speciation happens but concludes by saying speciation is impossible. Let me restate what I think you're trying to say in order to make sure everyone understands:

• Decreased genetic diversity can create significant new traits.
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• Increased genetic diversity cannot create significant new traits.
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• New traits sufficient to cause speciation is impossible.

Can you please confirm whether this is correct, particularly since it runs counter to the clarification I was seeking in my Message 752, to which you didn't respond.

I don't see how anyone could type such a paragraph and not see the self evident holes in their logic.Mutations increase the alleles and thus the probabilities. If in fact a species reaches the point where further speciation is impossible according to this bull farb, then what does happen to new mutations? Just piling up more diversity? And how is that new diversity different from the original diversity? According to Faith, the new diversity, for some unknown and not cited reason cannot be involved in speciation. Sure, Faith, this is a great argument.It is clear that we've always understood what you are saying Faith. It is also clear that adding mutations and drift to the mix is sufficient rebuttal.

Difficult to know which wiki article you refer to without links, so I am going to assume from other conversations (correct me if I'm wrong) that you mean:Founder effect - Wikipedia

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In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942,[1] using existing theoretical work by those such as Sewall Wright.[2] As a result of the loss of genetic variation, the new population may be distinctively different, both genotypically and phenotypically, from the parent population from which it is derived. In extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species.

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Simple illustration of founder effect. The original population is on the left with three possible founder populations on the right.

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In the figure shown, the original population has nearly equal numbers of blue and red individuals. The three smaller founder populations show that one or the other color may predominate (founder effect), due to random sampling of the original population. A population bottleneck may also cause a founder effect even though it is not strictly a new population.

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... as I know that you will be drawn like a moth to flame by the phrase "the loss of genetic variation" ...The problem is that initially those (all red) or (all blue) populations may appear different, they are not yet different species -- those combinations could and did appear in the parent population, and thus there is no way that they were genetically incompatible with others in the parent population --- yet. For one, Wikipedia is not a source of absolute knowledge, but for two what it says is not exactly what you have been arguing:

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... In extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species

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It doesn't cause speciation, in extreme cases it can lead to speciation. How? What I said in Message 686 was (emphasis added):

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No. The founder effect is the platform on which following populations are build. In order for speciation to occur there must be a genetic difference that inhibits interbreeding when populations reconnect. That difference is shown to be due to different fixed mutations.

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Yes, because the preponderance of evidence shows that mutations occur in every generation, that rarely do offspring have the exact same genetic elements of their parents, because the sun rises every day whether you see it or not. Many do not show up in phenotypes, but are platforms for later mutations that do, and mildly deleterious mutations can still be propagated if the phenotype as a whole is able to survive and breed. You seem to be confusing the appearance of beneficial mutations with the occurrence of all mutations. Most appear to be neutral (intially) or have negligible effect, and thus many are propagated because the whole phenotype is selected.Beneficial\deleterious are also often relative to the ecology (while viable\lethal are related to the individual), and when the ecology changes their relative importance to the survival of the individuals can change -- deleterious can become beneficial, beneficial can become deleterious (pocket mice and lava beds). Let's start with what "fixed" means ... from fixation (wiki)

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In population genetics, fixation is the change in a gene pool from a situation where there exists at least two variants of a particular gene (allele) to a situation where only one of the alleles remains.[1] In the absence of mutation, any allele must eventually be lost completely from the population or fixed (permanently established in the population).[2] Whether a gene will ultimately be lost or fixed is dependent on selection coefficients and chance fluctuations in allelic proportions.[3] ...

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In the process of substitution, a previously non-existent allele arises by mutation and undergoes fixation by spreading through the population by random genetic drift and/or positive selection. Once the frequency of the allele is at 100%, i.e. being the only gene variant present in any member, it is said to be "fixed" in the population.[1]

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So you can't have "fixed RARE alleles" as a fixed allele is the only allele. Because that is how you get something different. Because (a) that is what happens over time, and (b) genetic incompatibility arises between fixed alleles in a breeding population. If you have 'a' (original) and 'A' (derived) alleles in a population and 'b' (original) and 'B' (derived) alleles (at a different loci) then the mating possibilities are: If a mutation arises and is not compatible within the breeding population then it perishes from the population. So of these possible combinations only AB is not necessarily viable while the others necessarily are. If this were within a single breeding population you would have a potential for depressed reproductive\survival results, but not genetic incompatibility, and this would tend to eliminate the new mutations over time.But with population isolation the new mutations that spread in each population are backwardly compatible with the (other loci) alleles of their parent populations. Getting back to the "V" diagram again: When each branch evolves independently with different new alleles becoming fixed within their populations they are each backwardly compatible with the (other loci) alleles of their parent populations, but not necessarily compatible with different new fixed alleles in the other population, as that is not tested within either subpopulation. That opens the door for genetic incompatibility to occur ... that is what makes incompatibility possible.EnjoyEdited by Admin, : Fix dBCodes.

In one way, and one way only, I have to agree that Faith is correct about genetic stagnation and inbreeding. It will cause inferior specimens of the species and obvious loss of mental capabilities. In the wild, these inferior specimens are weeded out by natural selection. In the human population, these inferior specimens end up in government.

I'm not sure where the "significant" enters in here. I say that decreased genetic diversity is NECESSARY to microevolution, which is the formation of new traits in a reproductively isolated subpopulation so that together they eventually create a characteristic "look" to that subpopulation -- at which point it should probably be regarded as a subspecies or "race." I wouldn't say that or perhaps I'm not sure what it means. It can create traits so why not significant ones? However, they wouldn't combine with other traits to form a recognizable subspecies as I describe above so perhaps in that sense the traits aren't as "significant." The thing is the additive processes like mutation or migration add a random scattering of traits in a population, rather than forming a new species out of them. My claim is that it takes the "subtractive" processes: natural selection or random selection through population splits, to do that. And if speciation is the point where a new species is supposed to form it requires those selective processes to get there. and it's those subtractive/selective processes that reduce genetic diversity. Yes, merely adding new traits won't lead to speciation or even to the formation of a new subspecies. That requires an identifiable collection of allleles / traits in reproductive isolation over some number of generations. A population split tends to reduce genetic diversity and the smaller the population the greater the reduction. So you are getting new traits by losing genetic diversity. As you do in domestic breeding although it's different in not being random. I think Message 752 threw me and I didn't know how to answer. I guess I'd respond now to this: I mean "actively evolving," or undergoing microevolution, which means producing new traits by sexual recombination in a reproductively isolated subpopulation, which should start showing up in the first generation with new allele frequencies but take some number of generations to acquire a population-wide new set of characteristics that might be considered to be a new subspecies. On the other hand, a random collection of new traits scattered through a larger population aren't actively evolving / microevolvin, even if they are considered to be part of the process of evolution overall.You started this post saying: Which made me wonder if you'd missed some things I'd said previously about speciation, such asin Message 710:

I haven't said anything about "genetic stagnation" let alone anything about creating inferior specimens. Loss of genetic diversity doesn't necessarily imply that although it can. Even the drastic loss of genetic diversity in a bottleneck doesn't always imply that. The cheetah has some genetic problems but it's also a magnificent animal that doesn't show any supposed inferiority due to its genetic depletion.

Now I am confused, too.
Are you arguing for evolution or against it?
Because it looks like you're agreeing that there is proof of dwindling genetic diversity, which according to your statements proves evolution.

I'm just trying to clear up some confusion. "Significant" was your terminology. In your Message 735 you were distinguishing between mutations that you claimed could only produce "insignificant" and "inconsequential" new traits on the one hand, and new allele combinations that could produce "completely new traits and functions" on the other: And in this message you go on to say: And all the above from your two messages seems completely consistent with this point:

• Decreased genetic diversity can create significant new traits.

I think your objection just boils down to that I didn't use the exact same words that you used in the exact same way that you used them, so only if the above is incorrect in some meaningful way, could you please explain how it is incorrect? Yes, exactly. It can create traits, so why not significant ones? That's the precise point I'm trying to get clarity on. I originally requested clarification because it didn't make sense that mutations could increase genetic diversity and create new traits, but only "insignificant" and "inconsequential" ones. This doesn't make sense either. If we give our loci names like A, B, C, D, etc., and we give the existing alleles for each locus names like A1, A2, A3, etc., and we give new alleles for each locus created through mutation names like Am1, Am2, Am3, etc., then you're saying that significant new traits could be created by this shift to a new allele combination: But that significant new traits could not be created by this other shift to a new allele combination that happens to include a mutation at loci B: Let me repeat once more that I'm not trying to debate you. I saw what looked to be contradictions and am seeking clarification.Here's another contradiction that is bound to confuse people: So let me restate, and please let me know if this is incorrect:

• New traits in a main population cannot cause speciation under any circumstances.
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• New traits in a small daughter population can cause speciation after a number of generations.

And finally: Repeating this confusing statement is only bound to create more confusion. This discussion has reached the point where most of the effort involves trying to figure out what you mean. Nobody is going to know what you mean by "speciation exists but it isn't speciation." Speciation already has a definition, so please don't try to redefine it. If you don't think speciation as defined by the science of biology can happen, then please say so plainly.Summarizing, these are the points that I think summarize your position, please correct as necessary:

• Decreased genetic diversity can create significant new traits.
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• Increased genetic diversity cannot create significant new traits.
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• Speciation as defined by the science of biology is impossible.

Edited by Admin, : Fix link to Message 735, which had been incorrectly entered as Message 732.

Just a small point Faith, Macroevolution in science means (and always has meant) speciation, and the formation of nested hierarchies.That this is impossible would astound several people who have actually observed speciation and the formation of nested hierarchies. This is sometimes called microevolution, however this is the process through which all species evolve and all evolution occurs at the breeding population level.If we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop combinations of traits that are observably different from the ancestral parent population. We saw this pattern with Pelycodus where different species were defined as we went from P.ralstoni to P.jarroviiIf anagenesis was all that occurred, then all life would be one species, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life. The reduction or loss of interbreeding (gene flow, sharing of mutations) between the sub-populations results in different evolutionary responses within the separated sub-populations. Each population then responds independently to their different ecological challenges and opportunities, and this leads to divergence of hereditary traits between the subpopulations, both to adapt to different ecologies and to reduce competition, as seen at the top of the Pelycodus diagram.Scientific macroevolution has occurred, it has been observed, and it is a fact that speciation and the formation of nested hierarchies does occur.Enjoy

Percy, you totally misunderstood that. I was making a concession to NoNukes' distinction between mutations producing "mere" alleles as opposed to the more "significant" whole genes. It was my terminology but it was aimed at characterizing HIS concept. I have no investment in the distinction but since he does I was saying it woujldn't make any difference to my argument anyway.I'll have to come back to the rest of your postlater.Edited by Faith, : No reason given.

But if speciation is not really a new species but just a subspecies that has lost the ability to interbreed with other subspecies, and if as a matter of fact it possesses reduced genetic variability, then it is sheer illusion to call it speciation. Which is not based on any kind of evidence of relatedness between the different groups but is only an appealing mental construct imposed on the facts. I suppose it would. But those things aren't impossible, they just aren't what they are interpreted to be. Yes, that's the typical definition I'm challenging. Have you read any iof my argument at all? And they do, through normal microevolution as I've been laboriously describing it, which reaches a natural end point where macroevolution should begin but can't because of genetic depletion.Edited by Faith, : No reason given.

This sentence seems to deny the essence of evolution without making a single argument for its truth. It is at the point of the loss of ability to interbreed that diversity between groups can really begin. New diversity added to the sub species is almost guaranteed not to appear in the parent species.We have not talked much about the issues that would result in animals becoming non-inter fertile, but there seems to be plenty of evidence that the mechanism for such things cannot be mere re-mixing of alleles. Instead something that interferes with the matching of genetic material during meiosis must be involved. In short that means there is no need to postulate some kind of allele frequency change that requires isolation into smaller less diverse groups. Almost certainly a mutation is involved.Edited by NoNukes, : No reason given.

You're right that the cheetah is magnificent and has some genetic problems. Otherwise, you're completely wrong.The cheetah struggles to survive today because of those genetic problems in the context of habitat destruction and a small, scattered population. Those genetic problems include low sperm quality, further hobbling their recovery as a species to a relatively secure population size. A. bunch of scoundrels who participate in the evolution and climate change conspiracies--scientists and their activist thugs--work hard to preserve enough habitat to enable their recovery.In the meantime, perhaps their greatest danger is genetic homogeneity--like clone-planted reforestation, one pathogen could wipe them all out.If those scoundrels succeed, the cheetah population may again develop greater genetic diversity: the greater the diversity, the greater the possibility of a surviving, viable population in the face of climatic bottlenecks and pathogens alike.If genetic change worked the way you claim, we'd all be dead.

This is what you always say, and this is why you must clarify what you mean. In this case you may have totally misexplained it, but I totally understood it. I read your post. You quoted NoNukes, I know he said that mutations can create new genes and loci. But in your reply you said that mutations "would only make alleles for the existing genes for those little insignificant traits" and that with mutations "all you are getting is new variations on those inconsequential traits." You contrasted these minor effects with the "completely new traits and functions" that you keep telling us are the result of new allele combinations and reduced genetic diversity.I'm not trying to debate you, Faith. I'm only asking you to clarify some puzzling and/or confusing statements you've made. If you meant something other than what you said then please just tell us what you meant. But it only further confuses things to claim those words meant something other than what they very clearly mean. Don't bother with my previous post. Just clear up for everyone whether the following accurately captures your views, and if not then please just provide simple and clear corrections. If you do accept that speciation is possible, then there are these:

• New traits in a main population cannot cause speciation under any circumstances.
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• New traits in a small daughter population can cause speciation after a number of generations.

And then there are also these:

• Decreased genetic diversity can create significant new traits.
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• Increased genetic diversity cannot create significant new traits.
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• Speciation as defined by the science of biology is impossible.

I'd like to get some clarity so that we can avoid further claims that your position isn't understood.

This represents an attempt to redefine the term "speciation" and is disallowed. Once two subspecies lose the ability to interbreed then they are two different species. It doesn't matter what caused the inability to interbreed. Even if you won your argument that only reduced genetic diversity can have any significant phenotypic impact, they would still be two different species.