|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
Faith  Suspended Member (Idle past 1474 days) Posts: 35298 From: Nevada, USA Joined: |
|
Thread Info
|
|
|
Author | Topic: Evolution Requires Reduction in Genetic Diversity | |||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13043 From: EvC Forum Joined: Member Rating: 2.3 |
Faith writes: Adding genetic diversity to a population by any means at all, migration or mutation or whatever, adds new phenotypes but doesn't do anything to make a new species out of them. That takes reproductive isolation of a particular set of those traits breeding together over some generations. It doesn't matter if the diversity is added to a large population that subsequently splits, or if it is added at the end of a series of populations, to a subspecies or new species, the same process has to occur for the formation of further species: reproductive isolation of new traits breeding together, and that will reduce genetic diversity (the number of allelic possibilities)which makes further evolution impossible. So you get new diversity and the same thing has to happen and around we go. Evolution, meaning macroevolution, meaning evolution as understood by the Theory of Evolution, really is impossible. 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:
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.
|
|||||||||||||||||||||||||||||||||||||||||||
NoNukes Inactive Member
|
It doesn't matter if the diversity is added to a large population that subsequently splits, or if it is added at the end of a series of populations, to a subspecies or new species, the same process has to occur for the formation of further species: reproductive isolation of new traits breeding together, and that will reduce genetic diversity (the number of allelic possibilities)which makes further evolution impossible. 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. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams
|
|||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined:
|
The quote on Wikipedia seemed to say that speciation can occur from the normal combinations of alleles present from founder effect so you appear to be arguing with that quote. 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
quote: ... 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.
The quote on Wikipedia seemed to say that speciation can occur from the normal combinations of alleles present from founder effect so you appear to be arguing with that quote. For one, Wikipedia is not a source of absolute knowledge, but for two what it says is not exactly what you have been arguing:
quote: It doesn't cause speciation, in extreme cases it can lead to speciation. How? What I said in Message 686 was (emphasis added):
quote: Besides, you are assuming mutations without showing that there are any mutations there. ... 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.
It's often said that mutations simply do not appear frequently enough to have any kind of beneficial effect so how can you assume they're occurring here? 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).
Why do they have to be fixed "mutations" anyway? The idea seems to be that fixed RARE alleles is the point, why do they have to be mutations? Let's start with what "fixed" means ... from fixation (wiki) quote: So you can't have "fixed RARE alleles" as a fixed allele is the only allele.
Why do they have to be ... "mutations" anyway? ... Because that is how you get something different.
Why do they have to be fixed ... 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:
ab, aB, Ab and AB 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. Enjoy Edited by Admin, : Fix dBCodes.by our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
|
|||||||||||||||||||||||||||||||||||||||||||
mikechell Inactive Member
|
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.
evidence over faith ... observation over theory
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1474 days) Posts: 35298 From: Nevada, USA Joined: |
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. 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."
Increased genetic diversity cannot create significant new traits. 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.
New traits sufficient to cause speciation is impossible. 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.
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 think Message 752 threw me and I didn't know how to answer. I guess I'd respond now to this:
But alleles being passed on randomly within a population is most definitely part of microevolution, so I don't think you mean "microevolution" either. 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:
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. Which made me wonder if you'd missed some things I'd said previously about speciation, such as in Message 710:
My argument is that what is called speciation and regarded as the springboard to further evolution is an illusion. Of course the situation called speciation exists but it isn't speciation and more to the point, when this condition is reached, genetic diversity is likely to be so limited there is no possibility of further variation, making the whole theory false.
The event is quite real though, and serves to prove the creationist view instead, which is that all evolution is only microevolution preprogrammed into the genetic system of each separate Species. This system of built-in variation will reach its built-in limits if pursued to that point called Speciation, or even close to it, where the ToE absurdly assumes a new species has formed with further evolutionary possibilities. In reality what has happened is that evolution has come to its genetic outer limits. So this whole scenario is evidence for the Creationist view against the ToE.
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1474 days) Posts: 35298 From: Nevada, USA Joined: |
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. 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.
|
|||||||||||||||||||||||||||||||||||||||||||
mikechell Inactive Member |
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. evidence over faith ... observation over theory
|
|||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13043 From: EvC Forum Joined: Member Rating: 2.3
|
Faith writes: I'm not sure where the "significant" enters in here. 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:
Faith in Message 735 writes: No, they do add diversity, or would if they actually make viable alleles, which I doubt, but they would only make alleles for the existing genes for those little insignificant traits, hardly ever if at all an actual new gene. So all you are getting is new variations on those inconsequential traits, you are NOT getting the "completely new traits and functions" evolution requires. And in this message you go on to say:
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." And all the above from your two messages seems completely consistent with this point:
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?
I wouldn't say that or perhaps I'm not sure what it means. It can create traits so why not significant ones? 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.
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." 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:
A1, B1, C1, D1 => A1, B2, C3, D2 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:
A1, B1, C1, D1 => A1, Bm1, C3, D2 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. 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:
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. So let me restate, and please let me know if this is incorrect:
And finally:
Which made me wonder if you'd missed some things I'd said previously about speciation, such as in Message 710:
My argument is that what is called speciation and regarded as the springboard to further evolution is an illusion. Of course the situation called speciation exists but it isn't speciation and more to the point, when this condition is reached, genetic diversity is likely to be so limited there is no possibility of further variation, making the whole theory false. The event is quite real though, and serves to prove the creationist view instead, which is that all evolution is only microevolution preprogrammed into the genetic system of each separate Species. This system of built-in variation will reach its built-in limits if pursued to that point called Speciation, or even close to it, where the ToE absurdly assumes a new species has formed with further evolutionary possibilities. In reality what has happened is that evolution has come to its genetic outer limits. So this whole scenario is evidence for the Creationist view against the ToE. 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:
Edited by Admin, : Fix link to Message 735, which had been incorrectly entered as Message 732.
|
|||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined:
|
Just a small point Faith,
... Evolution, meaning macroevolution, meaning evolution as understood by the Theory of Evolution, really is impossible. 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.
(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats. 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.
(2) The process of lineal change within species is sometimes called phyletic speciation, or anagenesis. We saw this pattern with Pelycodus where different species were defined as we went from P.ralstoni to P.jarrovii If 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.
(3) The process of divergent speciation, or cladogenesis, involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other. 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. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1474 days) Posts: 35298 From: Nevada, USA Joined: |
I'm just trying to clear up some confusion. "Significant" was your terminology. In your Message 732 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 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.
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1474 days) Posts: 35298 From: Nevada, USA Joined: |
... Evolution, meaning macroevolution, meaning evolution as understood by the Theory of Evolution, really is impossible.
Macroevolution in science means (and always has meant) speciation, 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.
and the formation of nested hierarchies. 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.
That this is impossible would astound several people who have actually observed speciation and the formation of nested hierarchies. I suppose it would. But those things aren't impossible, they just aren't what they are interpreted to be.
(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats. Yes, that's the typical definition I'm challenging.
This is sometimes called microevolution, however this is the process through which all species evolve and all evolution occurs at the breeding population level. Have you read any iof my argument at all?
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. 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.
|
|||||||||||||||||||||||||||||||||||||||||||
NoNukes Inactive Member
|
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. 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. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams
|
|||||||||||||||||||||||||||||||||||||||||||
Omnivorous Member Posts: 3991 From: Adirondackia Joined: Member Rating: 6.9
|
Faith writes: 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. 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."If you can keep your head while those around you are losing theirs, you can collect a lot of heads."
|
|||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13043 From: EvC Forum Joined: Member Rating: 2.3
|
Faith writes: Percy, you totally misunderstood that. 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.
I'll have to come back to the rest of your post later. 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:
And then there are also these:
I'd like to get some clarity so that we can avoid further claims that your position isn't understood.
|
|||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13043 From: EvC Forum Joined: Member Rating: 2.3 |
Faith writes: 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. 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.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024