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Author Topic:   Evolution Requires Reduction in Genetic Diversity
PaulK
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Message 6 of 1034 (691644)
02-23-2013 2:24 PM
Reply to: Message 1 by Faith
02-22-2013 6:14 PM


Evolution requires increases and decreases in Genetic Diversity
I think that the best way to start this discussion is with a very simple explanation of how evolution is meant to work. There are many, many complications but we need to agree the basics first.
Adaptive evolution is held to be the interplay of two processes, mutation and selection. Mutation provides a stream of variations while selection is the directional aspect, culling diversity. Evolution has no definite endpoint other than extinction.
Selection is quite simple to understand. All life inherits some traits from it's parents or parent. Variation in these traits leads to variation in fitness which is defined in terms of producing offspring who manage to reach the point of reproducing themselves. Those individuals with the greatest fitness will tend to produce more offspring, and therefore their traits will tend to become more common in the population. Fitness is also affected by the environment - a trait may be good in some environments and bad in others - and environments do change over time.
If we are going to compare natural selection to a dog breeder the nearest equivalent would be a pragmatic breeder of working dogs. A breeder who is concerned with the practical benefits of the traits he can select, and not with any abstract idea of breeds. A breeder who is happy to take in the new, and adapt to changing demands, rather than pursuing an aesthetic "perfection".

This message is a reply to:
 Message 1 by Faith, posted 02-22-2013 6:14 PM Faith has replied

Replies to this message:
 Message 9 by Faith, posted 02-23-2013 7:45 PM PaulK has replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 12 of 1034 (691682)
02-24-2013 3:15 AM
Reply to: Message 9 by Faith
02-23-2013 7:45 PM


Re: Evolution requires increases and decreases in Genetic Diversity
quote:
The theory I've been pursuing for years is that it does, and I realize it's my job to prove it.
OK, so we're talking about your theory of evolution, and falsifying it won't have any impact on the standard scientific theory. As far as I know this is the first time you've clearly said this and I don't remember seeing anything that even loosely implied it before recent discussions. The past threads would have likely gone better had you made it clear.
In fact I suggest you come up with some terminology that makes it clear in the future so we know when you're talking about your theory.
quote:
There is no argument with this basic notion except perhaps to suggest that it is overemphasized in the range of actual occurrences in nature.
There are, in fact, arguments within evolutionary science as to how far features are the direct products of selection.
quote:
For my purposes it doesn't matter which context you choose, including nature's own "selections" by the fairly frequent and often accidental occurrences that bring about reproductive isolation of separated portions of a population, leading to new phenotypes by reduced genetic diversity there as in all other cases.
The point is that the mechanisms of natural selection are incapable of working towards an abstract ideal, like a "perfect" exemplar of a breed. As a consequence genetic diversity will often tend to increase, as selection fails to remove new variations that have little effect in the current environment.
So, to go back to your theory, you need a selective mechanism which will work the way that your theory requires.

This message is a reply to:
 Message 9 by Faith, posted 02-23-2013 7:45 PM Faith has replied

Replies to this message:
 Message 33 by Faith, posted 02-25-2013 8:02 AM PaulK has not replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 29 of 1034 (691738)
02-25-2013 3:34 AM
Reply to: Message 20 by Faith
02-24-2013 7:32 PM


Re: mutations
quote:
My point was that it just doesn’t happen as much as you apparently think it should, as breeders aren’t always having to fight new traits, at least after the breed is well established.
Then your point was both badly phrased and based on a misunderstanding of the timescales involved. We are talking of periods of tens or hundreds of thousands of years for natural species, not the few hundred we have limited records for. Indeed I don't think you can even get a good estimate of how many have occurred in the last few hundred years.
quote:
Even in nature we see pretty homogeneous groups maintaining their character don’t we? Populations of identical individuals keeping to their own kind, birds of a feather flocking together as the saying goes. Darwin’s Galapagos turtles were of an identifiable kind, differing in identifiable ways from those on the mainland. His finches had something like four different styles of beaks that specialized in four different ways of getting food, and these types hung out with others of their same beak. There does seem to be a strong family inclination in nature.
But let us note that these are all species and we've no reason to think that they are anything like as genetically impoverished as your breeds. A simple idea that they "all look the same" is hardly a measure of genetic diversity.
quote:
But that’s not a particularly important point. the main point about mutations of course is the claim that evolution depends on increasing diversity which mutations supposedly supply. I’ve already argued that as soon as a trait is selected, whether it originated by mutation or by simple sexual recombination of existing alleles for that characteristic, whether by chance or conscious intent, that very selection reduces the genetic diversity of the breed or wild population. My claim is that this IS the definition of evolutionary change, there is no other, it can only proceed by reducing genetic diversity. Wherever there is any kind of selecting or culling process whatever, reduced genetic diversity is the result.
But of course, the fixed allele is - generally - free to mutate too, perhaps modifying the trait or contributing to a new one. If you define evolution solely in terms of natural selection leaving out mutation then you get the result you want, but it's still a misrepresentation of the theory.
quote:
Again, the point was it doesn’t happen at such a rate as to interfere with breeding programs. But the second point I’d make here is that there seems to be this odd idea that it will always be the MUTATION that is selected for. I’ve noticed this before. I think it’s probably just a case of imprecise thinking but thought I’d mention it. Why should a mutation be any more likely to be selected than other alleles already in the population?
Of course we have evidence of mutations contributing to breeding programs and I very much doubt that there would be many records that let us work out where mutations have been removed by breeders, so I don't think you have enough information to make an argument here.
Your second point is another mistake. I find it very hard to believe that you've never seen any mention of deleterious mutations and I know that I referred to stabilising selection in a reply to you quite recently.
quote:
1) First that even if they do create new alleles, once they are selected the population loses genetic diversity by eliminating the competing alleles as it develops whatever new phenotype is favored by the allelic mix. Doesn't matter if it's a mutation that is selected or not.
THe assumption there is that fixation is a very rapid process, and there is not an extensive period where multiple alleles exist. Indeed unless being selected for it takes a considerable time for an allele to reach fixation by drift.
quote:
2) And second even if they do create new alleles, they ARE just alleles, variations in the sequence along the gene locus, and whatever changes occur can only occur with respect to whatever that gene does. If it governs fur color then the allele may produce a new fur color. But you aren’t going to get any changes beyond these limited changes within the purview of the gene itself and it really doesn’t do more than a pre-existing allele would do anyway.
What genes - and perhaps more importantly regulatory sequences do - can be quite subtle. And it can be possible to build on new traits, too - cumulative change is a major point in evolution However I don't really see the point you're trying to make even after that. A new variation is a new variation in whatever it is. You seem to be saying "just because it's different doesn't mean that it's different" which is rather obviously wrong.

This message is a reply to:
 Message 20 by Faith, posted 02-24-2013 7:32 PM Faith has replied

Replies to this message:
 Message 34 by Faith, posted 02-25-2013 8:41 AM PaulK has replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(2)
Message 38 of 1034 (691758)
02-25-2013 9:54 AM
Reply to: Message 34 by Faith
02-25-2013 8:41 AM


Re: mutations
quote:
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.
But we're NOT talking about just the formation of a species. To become successful that small population must expand outwards, and that's a prime time for expanding genetic diversity.
You see, the important issue is the strength of selection. When a species is under pressure every little advantage counts That's when you'd get reduction in genetic diversity. When the species is expanding, fitness is "easy" and even small disadvantages can spread. Even when the population is stable neutral mutations can and will spread through drift, and some may become beneficial or provide the basis for future beneficial mutations.
quote:
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.
I don't think you'd have any records for any domestic breed that would let you single out the number of mutations that have occurred.
quote:
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.
Given the aggressive level of selection and forced inbreeding I don't think that such conditions will often be encountered in the wild - and if they do I doubt that they would often be survivable. And let us note that breeds are not species. Obviously there's something more to speciation than what the breeders have done.
quote:
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.
Firstly the time it takes for the split to happen doesn't dictate how long ago it happened. Even if it took only a year to occur it could still have happened a million years ago.
Also they aren't breeds (the blue wildebeeste has five subspecies)
quote:
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.
OK. So we're going to need actual measures of genetic diversity.
quote:
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.
Yes, a small group split off a successful species will almost certainly have lower genetic diversity. But that's really not the whole of the story because the process needs the variation to recover, and it does.
quote:
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.
Which leads to the question of why isn't it normal for species to be as genetically impoverished as breeds ? If forming a new species involves reducing genetic diversity below that of a breed, shouldn't species all have really low genetic diversity ?
quote:
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.
And let us remember that these are bottleneck situations and - certainly at the level of DNA - the cheetah is recovering diversity.
Edited by PaulK, : No reason given.

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 Message 34 by Faith, posted 02-25-2013 8:41 AM Faith has not replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


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Message 73 of 1034 (691832)
02-25-2013 3:18 PM
Reply to: Message 61 by Faith
02-25-2013 2:35 PM


Re: mutations
quote:
If the diversity increases to any great extent you are going to lose your variety or breed
Is this based on your idea that selection is trying to create a "perfect" animal ? I'm still waiting to see an explanation of how that could work.
However, to return to the views of science, if a trait varies within a species then that variation is part of the makeup of the species. If a new variation were to arise the same would be said of that. It's just not an issue.
quote:
Breeders aren't always having to contend with new traits after a breed is established
Well we have had a couple of examples of new traits incorporated by breeders, and as I said we can't expect good records of discarded traits so this really doesn't tell us much. Not to mention the fact that genetic diversity covers rather more than gross morphology.
quote:
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
But so long as it is present it contributes to diversity. That's the point.
quote:
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.
Well no, to make a difference to diversity they have to exist in the population without taking it over. And even if they are selected they can do that for quite a time. If they are neutral then it's all down to drift which is even slower, especially in large populations.
So, what we should expect is a dynamic equilibrium that fluctuates according to the strength of selection. When selection is strong, the equilibrium is at a lower level, when it is weaker the level goes up.

This message is a reply to:
 Message 61 by Faith, posted 02-25-2013 2:35 PM Faith has replied

Replies to this message:
 Message 100 by Faith, posted 02-26-2013 9:16 AM PaulK has replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 95 of 1034 (691881)
02-26-2013 3:50 AM
Reply to: Message 84 by Faith
02-25-2013 5:44 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
A provocative title, and one that would need quite a bit of justification. On the face of it mutations WILL add to diversity.
quote:
It is hard to figure out how to get this said, but perhaps I'll eventually have a better way. I keep trying to show that whenever you have the creation of a new phenotype or breed you have the opposite of what evolution would need in order to be true, you have a situation with a built in ultimate ending point.
The problem here is that that is a relatively short part of a successful species' lifetime. We can't simply ignore the rest of it. (We can ignore unsuccessful species because evolution can certainly have some failures). And of course if your title was correct there is no reason to take an artificially constrained view that minimises the input from mutation.
quote:
You all keep answering: But no, there is also increase in genetic diversity through mutation, as if that is going to prevent this inexorable trend to to the ending point brought about by the selection processes.
On the face of it, it seems that it can and does. So the onus is on you to actually provide evidence that you are correct. Arrogantly declaring yourself to be right is simply not going to fly.
quote:
I've said that mutation only makes changes in the allele and that's part of it, since you'll never get beyond the boundary of the Kind or "baramin," beyond microevolution, with mere alleles for existing traits within the species that is evolving. All you'll get is variations on the traits that are built into the genome for that species. That is never going to lead to macro-evolution.
That's really confused, and besides a YEC belief not established fact. So it's not going to work as an argument.
quote:
And I've also said that mutation is only a source of alleles and it doesn't matter what the source is because once the selecting and isolating processes get to work on them to bring out a new phenotype you get the reduction in genetic diversity that always occurs in the formation of new phenotypes, and at the extreme there is no further evolution that is possible. Same as it does in breeding. Works the same in the wild. At the extreme you aren't going to get any mutations that could possibly save the day but you'll all claim you can and do. Sigh. It's all theoretical smoke and mirrors but you all seem content with that.
Obviously the only way to offset a loss of alleles is a gain of alleles. And I have to say the narrow focus on speciation events makes it look very much as if you are the one resorting to smoke and mirrors to try to hide the scope available for mutations to increase diversity.
quote:
Now I do think just these two observations are sufficient to show that mutation's additional genetic diversity isn't going to accomplish a thing for the ToE, and you are still going to end up with the reduced genetic diversity in the end that spells FINIS to the ToE. Perhaps I'll yet find a better way to say it, but it seems to me this really ought to be enough.
I don't think that either deserves to be called an observation. Both are just opinions and you need more than your personal opinion to convince an informed person. At this point it's still just "'cause I say so".

This message is a reply to:
 Message 84 by Faith, posted 02-25-2013 5:44 PM Faith has replied

Replies to this message:
 Message 96 by Faith, posted 02-26-2013 8:04 AM PaulK has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 97 of 1034 (691890)
02-26-2013 8:13 AM
Reply to: Message 96 by Faith
02-26-2013 8:04 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
But that diversity 1) only varies the traits within the genome of the species and 2) will be eaten up by selection in the process of producing new varieties anyway.
1) doesn't seem to be an objection, as far as I can figure it out - I'm hardly suggesting that the genome of some OTHER species would be affected. Probably it means something else but it's horribly unclear.
2) As written, isn't even an objection - it's entirely consistent with my view of diversity as a varying dynamic equilibrium. Presumably you mean that the extra diversity will always be eaten up and more - but even that would just be an assertion.

This message is a reply to:
 Message 96 by Faith, posted 02-26-2013 8:04 AM Faith has replied

Replies to this message:
 Message 98 by Faith, posted 02-26-2013 8:39 AM PaulK has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 99 of 1034 (691899)
02-26-2013 9:07 AM
Reply to: Message 98 by Faith
02-26-2013 8:39 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
Oh dear, the ways one can be misunderstood are quite astonishingly diverse. What I'm arguing in this thread, yes again and ad nauseam, is that the processes that bring about new phenotypes reduce the genetic diversity for that particular variety, such that eventually a point will be reached -- at the far extremes which may or may not ever be reached in reality for a particular line, but it's always the direction of the change --, a point that is where further new phenotypes can't be formed at all, which I'm saying is the end of evolution -- for that line of variation.
Yes, we know you assert that, but that isn't a REASON why the extra diversity doesn't count.
quote:
WHEREVER you get new varieties or phenotypes you get this phenomenon of reducing the genetic diversity and what that MEANS is that forming new "species" which one would have thought the ToE was all about, has an end point that must be the definition of the boundary of the Kind or Baramin or whatever you want to call it.
Pretty obviously the theory of evolution has to do rather more than this if it is to explain common ancestry from the earliest single-celled organisms to the more complex life forms found today. So it seems rather clear to me that you are talking about a Creationist theory of evolution, and not the one usually discussed in this group.
quote:
I consider this to be a DEFINITION of the limits of a Kind or Baramin. THEREFORE, if all mutations do is vary the traits within the genome of that Kind or Baramin they cannot contribute to any changes BEYOND the Kind or Baramin which presumably would be necessary if the ToE is right. EVEN if you should get mutations at that point which everybody here keeps hopefully asserting, they're going to be within the boundary of the genome of the Kind.
Given that we don't know of any such limits I hardly think you're in a position to claim that they not only exist but are so restrictive that they actually cause a problem.
quote:
Presumably what you need is a kind of "increased diversity that can change the structure of the genome itself if there's anything to the ToE but all you have is variations within the parameters of the genome, the Kind, the Baramin etc. etc. etc.
I'm not sure that we do to deal with ordinary speciation, although there is evidence of structural changes from gene duplication up to whole genome duplication.
quote:
I don't know if a mutation could produce neon violet fur in squirrels but if it could and for some reason it was good for the squirrel population all you would have is squirrels with neon violet fur, you would not have even the beginnings of a change toward a different species. And doesn't the ToE require that?
Which should tell you that you are thinking on rather too simplistic a level. If you look at the well-known transitional sequences you will see multiple changes between known fossils - and while they may have developed over a series of speciations - it's pretty clear that if evolutionary theory is correct your argument has to be wrong.
And one thing you don't apparently know - it's very hard to work out the effect of a gene in most cases. The example of fur colour in pocket mice is chosen because it is relatively easy to relate the gene to the effect. And then there are the effects of regulatory sequences. The whole thing is really very, very complicated.
quote:
You think in the supposed race between mutations and this inexorable process of genetic reduction I'm talking about as NECESSARY to the production of new varieties you're going to get a new species? Really?
I can't really make sense of this.
quote:
Well, if anybody wanted to bother to check I suspect that most of what has been said on this thread by everybody is nothing more than an assertion anyway.
That seems pretty much an admission that your argument hasn't got past "'cause I say so".

This message is a reply to:
 Message 98 by Faith, posted 02-26-2013 8:39 AM Faith has replied

Replies to this message:
 Message 102 by Faith, posted 02-26-2013 9:35 AM PaulK has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 105 of 1034 (691905)
02-26-2013 9:49 AM
Reply to: Message 100 by Faith
02-26-2013 9:16 AM


Re: mutations
quote:
The point as I think I've said is that mutations DON'T interfere with breeding programs, or the maintenance of homogeneous populations in the wild either. What changes populations is selection and isolation of the alleles/traits (Hey, how about "ISOLECTION" for a new term. Oh well), not their existence in the population even if mutation produces them. They'll just get passed around here and there if they aren't selected. but I can see that this was a point I probably should have avoided because it takes me away from my main argument.
It's hard to see how mutations could interfere with breeding programs. If they turn up they're either ignored, kept, or removed. Really, even there, you're arguing from ignorance - you have no idea of how many mutations turned up or what happened to them.
And let's be clear about wild populations - there's plenty of variation in them - with rare exceptions due to major bottlenecks. Why should additional variation be a problem ?
quote:
It has to be selected to have any effect on the characteristic phenotype of the species. Otherwise as I say above it just occurs here and there within the population.
I don't think this is much of an argument:
1) There is plenty of variation outside the "characteristic phenotype"
2 a) If the "characteristic phenotype" is based on describing the species as it is, then it is certainly possible for a new variation in a key trait to affect that as it is.
2 b) If the "characteristic phenotype" is not a description of the species as it is, how is it relevant ?
quote:
Which is irrelevant to this argument. New traits are not necessarily brought about by mutation, but can have been latent in the gene pool until some sequence of recombination events brings them to expression.
Let us note that that is your opinion and one that is not generally accepted.
quote:
And if they are selected for the breed, so what? They become part of the breed. And we're talking an occasional effect after a breed is established not a bunch of mutations showing up to blur the characteristics of the breed, which was my point.
Which only adds up to breeders doing their job - not an absence of mutations.
quote:
But not a diversity that makes any real difference. It's selection that makes the difference, and selection, or reproductive isolation/selection, and that's what reduces the genetic diversity, and it does have the last word. That's the part that's hard to get said convincingly but it does have the last word.
Why doesn't the diversity make a difference ? On what basis do you claim that the forces reducing diversity always get the last word ?
quote:
But they only MAKE the difference when they are selected. Just existing the population doesn't make the difference.
That's really not making a lot of sense. Just existing in the population is EXACTLY what they need to do to contribute to diversity.
quote:
True, long long times of stability without evolution happen too.
Long periods where there is little noticeable phenotypic evolution, but where genetic diversity is increasing.
quote:
True it's slower but it's the same process of creating a new phenotype by reducing the competing alleles which for that new variety is genetic reduction
But the slowness is the point. Because of that slowness we get diversity.
quote:
Sounds like this is YOUR theory, and I think you may need to phrase it more sharply, but my answer would be that dynamic equilibrium ain't gonna get you EVOLUTION
I think you'll find that my views are in line with the standard science.
Edited by PaulK, : No reason given.

This message is a reply to:
 Message 100 by Faith, posted 02-26-2013 9:16 AM Faith has not replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 106 of 1034 (691906)
02-26-2013 10:03 AM
Reply to: Message 102 by Faith
02-26-2013 9:35 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
Oh but we DO know of such limits. They occur all the time when breeding programs are too aggressive, when you have too few individuals from which you are breeding, or even when you've pursued a rigorous program of selection with a breed that isn't that genetically depleted. Eventually you run into genetic problems that make further breeding dangerous for the breed. That's one kind of end point. Breeders have learned that they must incorporate some "alien" genes if they want to keep their breed viable, which of course means compromising the perfection they are seeking but then they just look for a new standard.
But that isn't the limit we're looking for. It isn't a limit on what mutations are possible. It's just an expression of the fact that aggressive selection and inbreeding can rapidly deplete genetic diversity.
quote:
Yes I know your answer is BUT THESE AREN"T NORMAL, and normally you get MUTATIONS that save the breed from such depletion, but my answer to that is that in that case YOU AREN"T GETTING EVOLUTION EITHER. What I'm focused on is what brings about the NEW VARIETIES that presumably are the route to EVOLUTION. Bottlenecks DO bring about new varieties, you just don't like them because they demonstrate the end point of evolution so well in themselves. You keep thinking mutations are going to save them and all the others from the genetic deficiencies that prevent further evolution. All it COULD do is establish your "dynamic equilibrium" and that is not evolution.
Actually my dynamic equilibrium is necessary to evolution. It just contradicts your limited within-baramin idea of evolution which is why you don't like it. And I don't dislike bottlenecks as such, but I do dislike the idea of presenting them as the normal outcome of evolution because none of the current ones ARE.
quote:
Again if you put new alleles back into the breed, whether by mutation or reintroducing other gene sources into it, all you're going to get is that "dynamic equilibrium" you aren't going to get EVOLUTION. Evolution, the production of new phenotypes, the production of new varieties, same as the production of new breeds, REQUIRES the reduction of the genetic diversity to keep the genes for the breed free from competition.
I really do think this is obvious.
It isn't. You have yet to give any convincing reason why genetic diversity can't recover between speciation events. It IS obvious that it will to an extent. So why not to a level that prevents your inexorable decline in diversity ?

This message is a reply to:
 Message 102 by Faith, posted 02-26-2013 9:35 AM Faith has not replied

  
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 168 of 1034 (692139)
02-28-2013 1:48 AM
Reply to: Message 149 by Faith
02-27-2013 6:05 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
None of that has been SHOWN by the biologists, it's all BELIEVED ON FAITH and accepted on authority. Whenever a new trait emerges they call it a mutation. In most cases they don't KNOW that it's a mutation, it's just that their theory tells them it is.
I think you'll find there's more to it than that. But if a previously unknown heritable trait appears odds are that it is due to a mutation.
quote:
What actually happens in reality is that the processes of evolution come to an end by running out of genetic possibilities.
In REALITY. This is demonstrated in breeding and it is demonstrated all the time in the wild where conservationists are concerned about species endangered by genetic depletion.
Obviously you think that you are God, because otherwise there is no way you could honestly state that your opinions were reality. In actual reality there is no sign of this happening. That rapid depletion can occur and lead to problems (and often extinction) is entirely consistent with evolutionary theory. And let us note that the majority of cases are a consequence of human activity.
quote:
You CLAIM that mutations keep adding diversity so that this doesn't normally happen but you do not KNOW that. You know that there ARE mutations but you don't know what they actually DO in the population. Again it's an article of faith based on your theory telling you that's what has to happen.
We know that there are mutations. We know that they increase diversity at the level of DNA sequences. We know that mutations can have phenotypic effects. Which is a pretty solid basis for a position. But we have more, we have all the evidence for evolution, which can't be explained by your theory. So we have much more than an article of faith, we have a quite solid position. All you have is your assumption that it can't happen.

This message is a reply to:
 Message 149 by Faith, posted 02-27-2013 6:05 PM Faith has replied

Replies to this message:
 Message 195 by Faith, posted 03-01-2013 11:40 AM PaulK has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 191 of 1034 (692177)
02-28-2013 1:31 PM
Reply to: Message 173 by Faith
02-28-2013 9:08 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
Well, would you agree that if the faucet and drain are both open you aren't getting evolution? That is, you aren't getting the development of new varieties/species/breeds?
Definitely not.
quote:
If you are getting more increase in diversity than you are selection events you also aren't getting evolution, the development of new varieties/species/breeds.
Evolution isn't just the development of new species or subspecies. And anyway the increase in diversity is needed for the future development of new species and subspecies. (Your argument says so !)
quote:
{ABE: As a matter of fact you can't have both faucet and drain operating at the same time. The "drain" is supposed to stand for the selection/isolation processes but those bring about new phenotypes FROM the genetic pool. Must be more like add THEN subtract, add THEN subtract in reality}
That doesn't even make sense. The "faucet" is mutation and that is on all the time.
quote:
What you are getting is perhaps new traits appearing here and there in individuals within the population. But for evolution to occur, that is the development of a new population with new characteristics, a new "species," you MUST have reproductive isolation/selection.
Doesn't that seem true to you?
Well it seems poorly phrased. And it is far from clear that the usual model of speciation covers every case, It is certainly possible that some species come about from a more gradual transformation, affecting the entirety of the population,
quote:
This analogy really doesn't work though because this isn't a simple addition/subtraction issue and I wish I had a model for what it really is. If mutation is involved it could maybe be described as something like two steps forward, one step back. Add some diversity, knock it back with selection, add some more diversity, knock it back again.
You HAVE to knock it back, that is, you HAVE to reduce the genetic diversity to get a new phenotype, breed, variety, species, in the wild as well as in domestic breeding, though the most accessible example is what happens in domestic breeding. If mutation really is involved it could only be a start-stop sort of thing along the lines I'm describing here, the continual adding of mutations merely delaying the inevitable.
And here we come back to the idea of equilibrium. Now, let us grant that with the usual model of speciation the genes of the incipient species are less diverse than those of the parent population. It does not follow that they are less diverse than those of the parent population when it was an incipient species. This is the point you keep overlooking. The diversity of the parent population will have increased in the time between speciation events. Therefore there is no need for an inexorable reduction in genetic diversity.
quote:
Mutations would keep changing the gene pool which sets back the selection effects, but it can't keep them from occurring IF you're going to get new "species." If all you get is balance or stasis, water in water out, again you aren't getting the production of new species, you aren't getting evolution.
But of course you will because mutation does NOT act against selection in any way that would stop speciation. It does not prevent the loss of old alleles, it is NECESSARY to the rise of new alleles to replace the old. Your version of evolution is unworkable.

This message is a reply to:
 Message 173 by Faith, posted 02-28-2013 9:08 AM Faith has not replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 196 of 1034 (692254)
03-01-2013 12:26 PM
Reply to: Message 195 by Faith
03-01-2013 11:40 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
According to my model on the other hand, I would say that the odds favor its having been latent in the gene pool and then brought to expression in a combination that's rare for that gene pool through mere sexual recombination.
I'd say that your model is wrong, but I suspect that it's more likely that you don't really have a model, only an assumption. If it's previously unknown then the combination is rare and unlikely to be passed on to the next generation with anything like the probability we'd see with a mutation. So, it wouldn't really be heritable.
quote:
Yes I understand that the argument I'm facing here involves the claim that breeding methods don't model evolution in the wild, but it IS my argument that the principles are the same no matter who or what is doing the selecting.
It's not the principles. It isn't even just the differences in application - it's also the results. Species are not breeds.
quote:
Since it has been acknowledged by at least a few here that developing new breeds does involve reducing genetic diversity through mere selection of particular traits, and it's not an unreasonable idea that selection processes in the wild would operate in the same way, then the same kinds of processes would have to tend to the same conclusion, and they do, as exampled I believe in speciation events. Except of course in the wild the selection processes can be quite random such as migration and geographical isolation of a new gene pool which is not usually as small as those used in breeding, rather than caused by anything as actively selective as Natural Selection, though that may operate as well in some situations.
That there is a strong similarity is not being disputed. The argument is more about what is going on at OTHER times.
quote:
You all assume (without proof) that the traits chosen for breeding are created by mutation and there really isn't any way I can prove you wrong, but I don't see how you could claim that when the same trait is selected generation after generation with the effect that the chosen trait becomes strikingly large and elaborate, that mutations for each of those expansions and elaborations were the cause in each generation. Not if mutation is truly random you can't. The more reasonable explanation is that there is something in the genetic design itself that is capable of such elaborations.
If you paid attention you'd note that I consider mutation to be a relatively small influence in the case of selective breeding, larger in the case of speciation (likely often a cause of reproductive incompatibilities) but ultimately more significant over the whole lifetime of a species.
quote:
IF you are really observing a mutation and not confusing it with a normally occurring latent allele. But what KIND of diversity is NOT known in all cases. What is best known is the mutations that cause genetic diseases.
The fact that mutations happen on a regularly basis is beyond question. So is the fact that the vast majority are neutral, having little or no effect.
quote:
Yes and no. You are all more or less willing to accept ANY kind of change as valid in supporting your position, including deleterious changes. That isn't impressive to someone who thinks evolution has to produce changes that can be useful to the organism, no matter how cleverly you rationalize the possibility of a disease process sort of becoming useful in various contexts. Which as far as what is actually known is concerned is a very rare occurrence and the only one I can think of at the moment is the fact that sickle cell anemia protects against malaria. Not a hopeful situation for evolution it seems to me but then who am I to have an opinion?
Just because it's hard to gather direct evidence - especially for the hyper-critical enemies of science like you - doesn't mean that the critics must be assumed to be correct. If you want to assume that beneficial mutations can't happen, be my guest, but don't expect me to believe it without reason.
quote:
You aren't listing your evidence here but as I've encountered it most of the actual evidence that IS evidence is just as good evidence for creation as it is for evolution, often better, but besides that your evidence often amounts to wild interpretations, as of the fossil record, which creationists rightly laugh at. Or finding that since the octopus has an eye most similar to a human eye that proves that the human eye evolved even though there is no known genetic path, or even theoretical genetic path, that could have brought that about. And that sort of nonsense is treated as "evidence." Chortle.
And yet the real experts and the real scientists working in the field unanimously disagree. All you have is a relative handful of religious apologists with a well-deserved reputation for dishonesty. That's the reality of it.
quote:
Not an assumption, this is really and truly what I recognized had to be true as I was following out arguments on this subject. Certainly no assumption. It was a very exciting discovery as a matter of fact. But of course proving it is an uphill battle, especially with all the evolutionists trying to throw me over the cliff. Good thing I bounce well.
I't's not a discovery. Which is why you haven't even managed a coherent argument for it yet. It's an assumption, and that's all it it.

This message is a reply to:
 Message 195 by Faith, posted 03-01-2013 11:40 AM Faith has not replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


(1)
Message 237 of 1034 (692369)
03-02-2013 5:34 AM
Reply to: Message 234 by Faith
03-02-2013 2:48 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
quote:
OF COURSE. Why are you saying this as if it's different from what I'm saying? Of COURSE the new "diversity" is going to be different and of COURSE that's why it's going to interfere with the formation of a variety that's already begun.
Surely you mean why it ISN'T going to interfere? A variation that isn't in the parent population will help make the child population distinct.
quote:
If you have new traits popping up in a new isolated population that haven't yet been worked through the population to form a characteristic phenotype or look to that population, but at that point OTHER new traits ALSO start popping up you'll NEVER get a coherent variety. It's like while a breeder is getting a new breed established having to contend with alien alleles all the time. That breed is never going to get established and the same thing has to happen in the wild. Instead of the homogeneous populations we actually see you'd have nothing but motley populations.
This is really not making sense. It looks to me as if you are arguing that if evolution worked as it is supposed to it would produce species as we see them, rather than the breeds produced by human breeders.
Let's start with this. The parent population has a "characteristic phenotype", yes ?
So it is possible to have as much variation as the parent population and still have a "characteristic phenotype", yes?
So adding new variations to the child population won't necessarily interfere with it having a characteristic phenotype, correct ? If you disagree, please explain WHY.

This message is a reply to:
 Message 234 by Faith, posted 03-02-2013 2:48 AM Faith has not replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 255 of 1034 (692401)
03-02-2013 4:06 PM
Reply to: Message 254 by Faith
03-02-2013 3:58 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Well I'm trying to understand your argument but you really need to explain it.
Please try answering Message 237 for a start.

This message is a reply to:
 Message 254 by Faith, posted 03-02-2013 3:58 PM Faith has not replied

  
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