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Author Topic:   Evolution Requires Reduction in Genetic Diversity
Percy
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Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


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Message 7 of 1034 (691660)
02-23-2013 6:09 PM
Reply to: Message 4 by Faith
02-23-2013 9:57 AM


Faith writes:
I did want to have the whole basic argument on the table at least which i guess you are saying is possible. And I'm amazed that you agree with that much of it, even, since I don't recall that ever happening when I argued it many times before. But best not to look a gift horse in the mouth.
If you're referring to the part about one route to speciation beginning with a subpopulation that possesses only a subset of all alleles of the species, then I think most everyone has always agreed about this.
Disagreement only arises when it is declared that increasing diversity is impossible, at which point discussion of mutations and selection begins. But the problem isn't whether increasing diversity is possible. The problem, given that reproduction involves imperfect copying, is how one would ever prevent increasing diversity?
--Percy

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 Message 4 by Faith, posted 02-23-2013 9:57 AM Faith has replied

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 Message 8 by Faith, posted 02-23-2013 7:35 PM Percy has replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(5)
Message 10 of 1034 (691672)
02-23-2013 9:03 PM
Reply to: Message 8 by Faith
02-23-2013 7:35 PM


Re: Thanks for Acknowledgments of the Claim of Reduced Genetic Diversity
Faith writes:
Odd then that it has never before been expressed to me. While I'm quite willing to keep the focus at least at first on the questions raised about mutations, I do have to say that nobody in my recollection in discussing this subject before has ever acknowledged that i am right about my claim that evolution in ANY context whatever leads to reduced genetic diversity.
No, no, you've misunderstood. It isn't evolution in the form of mutation and natural selection that causes reduced genetic diversity. It's the distribution of the population of an entire species into subpopulations across distinct geographical regions with differing environments that results in reduced diversity in the subpopulations when compared to the entire species. That's what I meant earlier when I used the term "by definition." Practically by definition any subset of a population will have less diversity than the entire population.
The actual process of evolution by means of mutation and natural selection can only lead to increased diversity because there is nothing to prevent the imperfect copying of reproduction.
Your description of the idea of course reserves the implicit claim that other routes do not encounter this problem of reduced genetic diversity. Since my argument is that there are no other routes I will at some point have to try to prove it. But we don't have to start there.
Of course there are other ways that speciation can happen. A homogenous population can be split in two by some geologic or environmental event, such as a river changing course, and then the two subpopulations, each with equal diversity, would evolve according to the requirements of the environments of the newly separated regions.
Or a population of a species can simply evolve over time into a new species.
--Percy

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(3)
Message 17 of 1034 (691693)
02-24-2013 9:57 AM
Reply to: Message 13 by Faith
02-24-2013 3:18 AM


Re: Thanks for Acknowledgments of the Claim of Reduced Genetic Diversity
Faith writes:
It's the distribution of the population of an entire species into subpopulations across distinct geographical regions with differing environments that results in reduced diversity in the subpopulations when compared to the entire species. That's what I meant earlier when I used the term "by definition." Practically by definition any subset of a population will have less diversity than the entire population.
Fine, that is true, but again nobody ever acknowledged that fact before...
It's central to ideas about how speciation occurs and was not only acknowledged but described in detail over and over again.
Also fundamental to modern concepts of evolution is that both increased and reduced genetic diversity *can* be a result of the evolutionary processes of mutation and natural selection (and this too has been said many times before). This is because mutation and natural selection are opposite forces. Mutation increases diversity, selection decreases diversity.
To make clear the point, a successful species whose range is increasing will experience burgeoning numbers and increasing diversity, while a failing species headed for eventual extinction will experience shrinking numbers and decreasing diversity.
...believe it or not "differing environments" is NOT what creates the new phenotypes.
Evolution does not describe environments as creating new phenotypes. Rather, an environment is more like the mold into which evolution is trying to find phenotypic fits.
The genetic situation itself is what creates the new phenotypes, the fact that a new mix of alleles forms the gene pool of the new population compared to the old.
Alleles are remixed during reproduction, providing additional variation upon which selection operates. And new alleles are a result of the imperfect copying that occurs during reproduction, and upon which selection also operates. Reproduction, mutation and selection, in other words evolution, are what create what you described as the "genetic situation."
The actual process of evolution by means of mutation and natural selection can only lead to increased diversity because there is nothing to prevent the imperfect copying of reproduction.
What you haven't yet grasped is that SELECTION always inevitably reduces genetic diversity.
I misspoke. What I meant to say is that change (not increasing diversity) is inevitable because of the imperfect copying of reproduction.
You can have mutations galore within a population but once you have selection of whatever mix of mutations -- or alleles however formed -- selection reduces genetic diversity in the new population. Selection brings a certain allele mix to expression in the phenotype BY ELIMINATING COMPETING ALLELES from the gene pool.
As I explained above, evolution can cause both increased and decreased diversity. Mutation and selection are working at cross purposes, mutations providing variation willy-nilly without regard to fitness, and selection pruning the variation that fits the environment least well. The environment plays a major role in deciding whether mutation or selection wins out as measured by allelic variation.
Each newly born person possesses, on average, approximately 100 random mutations, DNA sequences that are different from either parent. This is due to the imperfect copying of reproduction. As the human population grows variation can only increase because the mutational process is outrunning the selection process.
Actually they would evolve according to the particular mix of alleles in their gene pool, which may adapt to peculiarities in their environment certainly, but the environmental factor is not necessarily the driving factor.
Environment is not the only factor, but it is certainly the driving factor. This is self-evidently true because everywhere we look in nature there is adaptation to the environment. It's ubiquitous.
--Percy

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 Message 13 by Faith, posted 02-24-2013 3:18 AM Faith has replied

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(3)
Message 89 of 1034 (691863)
02-25-2013 8:45 PM
Reply to: Message 71 by Faith
02-25-2013 3:11 PM


Re: The effect of the flood bottleneck
Faith writes:
Wow, you guys object to the idea that God created anything but you seem to think a mutation occurred precisely for the purpose of protecting a mouse from a recent lava flow? Aren't mutations supposed to be RANDOM? But you think this one just handily showed up when needed?
Interesting strategy - when successfully rebutted say something else incredibly wrong-headed to distract attention.
Of course mutations are random with respect to fitness. You've been told this many times, and Taq didn't say anything that even remotely implied anything else.
A successful mutation isn't like a lottery where you're permitted to purchase only one ticket. It's like a lottery where you're permitted to purchase millions of lottery tickets because each generation receives millions of mutations.
With the mice, each individual in the population has dozens of unique mutations that it received at conception, and in a population of millions of mice that's tens or even hundreds of millions of mutations per generation. Mice in the wild probably live 2 to 3 years on average, so many generations can occur in a short period of time.
It isn't that the necessary mutation arises just when needed. It's that with millions and millions of mutations per generation, the odds that one is going to be advantageous to changed circumstances such as darker rocks is far from being minute.
--Percy

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 Message 71 by Faith, posted 02-25-2013 3:11 PM Faith has not replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 90 of 1034 (691866)
02-25-2013 9:16 PM
Reply to: Message 84 by Faith
02-25-2013 5:44 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Faith writes:
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.
This is the clearest statement you've made so far of how little sense your position makes.
You're arguing that new species are created by a reduction in genetic diversity that uses only a subset of the alleles of the original population, and you're also arguing that adding new alleles to the existing alleles doesn't contribute to speciation at all. You're also arguing that a subset of existing alleles can create new phenotypes, but new alleles cannot. Think about this, Faith. You're in effect arguing that you can get more variation from just bricks then you can from bricks and wood and concrete.
And then when people explain the nonsense back to you, instead of saying, "Oh, your'e right," and rethinking things, you instead claim everyone is building strawmen and misunderstanding your arguments and then go on to repeat the same nonsense.
--Percy

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 Message 84 by Faith, posted 02-25-2013 5:44 PM Faith has not replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
(1)
Message 103 of 1034 (691903)
02-26-2013 9:36 AM
Reply to: Message 98 by Faith
02-26-2013 8:39 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Faith writes:
Oh dear, the ways one can be misunderstood are quite astonishingly diverse.
It isn't that you're misunderstood. It's that you're speaking nonsense. It's being explained precisely how it is nonsense, but you can't accept that, so you claim, repeatedly, that you were misunderstood, and then you repeat all the nonsense from scratch. For example:
Faith writes:
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?
It is apparently your view that a new species can more likely form from existing variation than from novel variation. Does that really make sense to you?
If a subpopulation only has alleles that the main population already has, how can it be a new species? You can reduce and reduce the number of alleles in the subpopulation, but it will still consist only of alleles already in the main population and therefore can only be the same species.
If what you said had any truth whatsoever then breeders would be producing new species right and left, since breeding programs can take an organized approach to reducing diversity. But breeders aren't producing new species right and left, and that's because speciation to a great extent is dependent upon the novel variation contributed by mutation.
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.
You're the only one here throwing around unsupported assertions, and they're contradicted not only by reality but even simple logic. And then there's stuff like this:
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?
Do even you know what this means?
--Percy

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 Message 98 by Faith, posted 02-26-2013 8:39 AM Faith has not replied

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


Message 118 of 1034 (691944)
02-26-2013 1:48 PM
Reply to: Message 115 by New Cat's Eye
02-26-2013 1:01 PM


Catholic Scientist writes:
No, the genome had to gain the genetic stuff that produced corn. It still has all the genes to make maize, but now it has the additional genes that turn the maize into corn.
Reading up on this a bit, maybe corn isn't the best example for making the point that mutations are a significant contributor to variation. It seems that hybridization is believed to be the most significant factor leading to modern corn. Genes would have been both added and deleted, and new alleles would have been introduced and removed, but mostly not through mutations. I couldn't find much detail about corn mutations, though there's one theory that involves a significant mutation some thousands of years and ago, and sweet corn is apparently the result of a commonly occurring mutation.
--Percy

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


Message 122 of 1034 (691949)
02-26-2013 2:14 PM
Reply to: Message 116 by Faith
02-26-2013 1:21 PM


Re: Plant Breeding
Faith writes:
Nope, it always had the genetic capacity to produce corn but that capacity had to be brought out by selection.
See my Message 118 to CS explaining why corn might not be a good example for either side in the discussion because of the significant role played by hybridization, i.e., introduction and removal of genes and alleles from other closely related plants.
I've been accepting that mutation could create the material for selection to work on,...
It isn't that mutation "could" create new alleles and genes - it's that it *does*. The copying of genetic material during reproduction is imperfect. Almost every new life possesses a number of mutations. In the case of human beings it averages around 100 mutations in each newborn.
And naturally, once genes and alleles are present then selection will operate on them.
Actually the mutation idea doesn't make much sense. They made broccoli, cauliflower, and a few other edible plants from one rather scrawny plant. They chose plants with the largest flowers and kept breeding for that trait from generation to generation until they got this gigantic flower that is cauliflower. They did the same with whatever part finally developed into broccoli. It was all from the same scrawny little plant, simply favoring the part they wanted to become more desirable, big etc.
Plant breeders having human lifetimes, they cannot wait for the right mutation to show up in their greenhouses. If a mutation consistent with the qualities he's seeking happens to pop up then hallelujah, but he can't depend upon it. The details of the breeding programs for broccoli and cauliflower are lost to history, but looking this up a bit I see that both are easily hybridized, so again not helpful to either side.
You think by simply choosing plants with the biggest flowers you are going to get a mutation for even bigger flowers? Don't think so.
This would be correct, see my previous paragraph. Plant breeders cannot wait around for mutations. In a population of millions and billions of plants there will be huge numbers of mutations, but in the much more finite numbers in a breeder's greenhouse the number of mutations will be limited and unlikely to help.
--Percy

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 Message 116 by Faith, posted 02-26-2013 1:21 PM Faith has not replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


Message 126 of 1034 (691956)
02-26-2013 3:20 PM
Reply to: Message 123 by Taq
02-26-2013 2:42 PM


Re: Plant Breeding
When I looked this up earlier today I didn't find mutation mentioned much, while hybridization was mentioned a lot. The genetic differences described in your reference likely arose through introduction from related plants rather than through mutation.
Of course, if you go back far enough the origin of all genetic material is mutation.
--Percy

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 147 of 1034 (692090)
02-27-2013 5:42 PM
Reply to: Message 145 by AZPaul3
02-27-2013 4:58 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Given that no moderation issues have arisen I'll make a brief comment about this:
AZPaul3 writes:
How do breeders make new lineages and yet find no trace of these prior existing alleles in the parent populations?
Advantageous mutations occur only very rarely in the small populations that breeders can handle. Advantageous mutations *do* happen but cannot be depended upon. Breeders rely almost exclusively upon selecting desired features for breeding. Faith is correct that in general breeding programs reduce diversity.
In the plant world hybridization is a way of introducing new alleles and genes. Well, new to the plant receiving them.
And in the animal world breeders can cross-breed between species, or mix in non-pure breds to add diversity.
But mutations play an extremely minor role in breeding programs.
--Percy

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 172 of 1034 (692145)
02-28-2013 8:46 AM
Reply to: Message 158 by NoNukes
02-27-2013 8:06 PM


Re: Mutations Don't Add Anything That Could Rescue the ToE
NoNukes writes:
But it is equally a mistake to discuss breeding programs as if they involved all of the mechanics involved in common descent.
Exactly. Breeding is an illustration of the power of selection, in other words, of only one half of the evolutionary process.
Diversity is like a bathtub with the faucet and drain both open. Whether the bathtub fills or empties is dependent upon which flow is greater. Faith hasn't yet enabled us to understand why she believes that diversity is under all circumstances diminished faster than it is augmented.
--Percy
Edited by Percy, : Grammar.

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Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 174 of 1034 (692147)
02-28-2013 9:20 AM
Reply to: Message 173 by Faith
02-28-2013 9:08 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Faith writes:
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?
But of course you're "getting evolution." That's the whole point of the analogy.
Mutations flow in through the faucet, adding diversity. Alleles and genes flow out through the drain, subtracting diversity. With all this flowing in and out of alleles and genes, their mix in the bathtub is undergoing continuous change, which is the basis for phenotypic change. Whether diversity remains constant or increases or decreases, the mix of alleles and genes will be always changing.
--Percy

This message is a reply to:
 Message 173 by Faith, posted 02-28-2013 9:08 AM Faith has replied

Replies to this message:
 Message 176 by Faith, posted 02-28-2013 9:28 AM Percy has replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 179 of 1034 (692153)
02-28-2013 10:02 AM
Reply to: Message 176 by Faith
02-28-2013 9:28 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Faith writes:
Not if evolution is the production of new species/varieties/breeds. All you get from the addition of mutations is more traits that COULD be the basis of a new species, but as long as they aren't being selected, no, you aren't getting evolution.
They *are* being selected. The drain is selection in this analogy. (You can't take the analogy much further - it was intended only as an illustration of how diversity is being added and taken away at the same time through the simultaneous processes of mutation and seleciton.)
You are getting lots of new traits here and there within the existing population. That is not evolution.
Yes it is evolution. New traits are a result of evolution. The discovery of new species does not happen as often today as it used to, but it still happens with regularity, and new traits is what marks a new species. New species of mushrooms were just discovered, identifiable as new because of unique differences in their spores (Two New Species of Mushroom Found in the Iberian Peninsula, Spain). And when paleontologists discover a fossil with previously unknown traits they announce the discovery of a new species.
You do not get a new species with new traits simply by reducing diversity such as happens with breeding. That's why breeders do not create new species.
No, it isn't a simple addition-subtraction thing. If alleles are flowing in you get stasis. If alleles are flowing OUT you are getting new phenotypes or varieties or breeds or species. Really they are two separate processes.
Yes, of course they are separate processes. The faucet is analogous to mutation, and the drain is analogous to selection. And the alleles and genes flowing in are not the same alleles and genes flowing out. It isn't stasis.
It is the BASIS for phenotypic change, because the gene pool IS the basis for phenotypic change, but you aren't GETTING phenotypic change until you get reproductive isolation and selection.
Without mutation you cannot get phenotypic change into a new species because the population will only have alleles and genes already possessed by the main population.
And selection occurs all the time regardless of reproductive isolation. Main populations are evolving, too, and possibly at a faster rate since they can draw upon a much larger inflow of new mutations.
But that isn't evolution if evolution is the production of new species, which is brought about by the selection and isolation of a portion of the gene pool.
Again, isolation and selection are not sufficient to form a new species. Without mutations all you have is the same alleles and genes as the original population.
All mutation does is add to the gene pool and that is not evolution,...
Yes, mutations are part of evolution, and for the creation of novel traits they are the essential part.
All mutation does is add to the gene pool and that is not evolution, that's as you say the BASIS for phenotypic change but if selection does not act on it you do not have phenotypic change and do not have evolution.
Of course selection operates upon mutation. Always, constantly, all the time. How could it not? Selection operates on all expressed parts of the genome, whether newly arisen through mutation or part of the original genome.
That mutation and selection are always active is why both faucet and drain were open at the same time in the bathtub analogy.
--Percy

This message is a reply to:
 Message 176 by Faith, posted 02-28-2013 9:28 AM Faith has replied

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 Message 185 by Faith, posted 02-28-2013 11:00 AM Percy has replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


(1)
Message 193 of 1034 (692214)
03-01-2013 9:15 AM
Reply to: Message 185 by Faith
02-28-2013 11:00 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Faith writes:
I know that, but if they are being selected and mutation is continuing to add to the gene pool you aren't getting a delineated recognizable species such as we see IN REALITY both in the wild and in breeding.
On the contrary, it's precisely what we see in reality. Almost every newly born organism possesses new mutations. The average human being possesses around 100 new mutations. Research has told us the mutation rate for many types of life, you can read about it over at the Wikipedia article on Mutation Rate.
Despite all these new mutations flowing into species population the world over, what you called "delineated recognizable species" continue to exist. That's because mutations, at least those that yield viable offspring, cause only tiny changes, and many are neutral.
Species are not eternal forms persisting forever. Species are plastic and change over time. As environments change species gradually change to adapt. Even when environments are constant species still change due to the genetic drift that is a result of the imperfect copying of reproduction that introduces new mutations.
This is all just some abstract idea that has nothing to do with what really happens.
It would be incorrect to say that this is only what we theorize might happen. It is precisely what we know happens because research has revealed it happening. We know that reproduction is almost always imperfect and causes mutations because there have been studies of life ranging from bacteria to mammals that reveal these mutations occurring. And we know the effects of mutations that create viable offspring are tiny. And we know that despite this species remain the same species over many, many generations. It probably takes at least 10,000 generations to produce a new species under normal circumstances.
I don't know what you would get in this scenario but it's something blurry and constantly changing,...
Yes, you're right. In reality species boundaries can be blurry, as illustrated by ring species that blend into each other at the boundaries of their territories. And yes, species are constantly changing, too, though not on human timescales.
That species boundaries can be blurry is responsible for the species definition problem. While we have no problem telling that cats and dogs are different species, its much more difficult when determining whether wolves and dogs are different species, or whether gray squirrels and red squirrels are different species. Biologists use a variety of methods to determine whether two phenotypically very similar species are the actually same species, but the most common is genetic analysis.
... NOT an identifiable new species which is what happens IN REALITY.
Any breeding population of organisms is an identifiable species, regardless of the particular qualities of the species.
(You can't take the analogy much further - it was intended only as an illustration of how diversity is being added and taken away at the same time through the simultaneous processes of mutation and seleciton.)
See above. This is all theory gone bonkers, it has nothing to do with reality.
No, it's not theory, it's reality. There is nothing that can stop the imperfect copying of reproduction that results in mutations, and environments are constantly imposing selective pressures on populations. All species populations are always simultaneously experiencing both mutation and selection. There's is no possible way to prevent either from occurring.
But to GET that new species the traits have to be SELECTED AND ISOLATED.
Without mutation you cannot get a new species. You can, for example, select for domesticity in wolves and foxes and find that other traits, such as curled tails, emerge at the same time, but neither domesticity nor curled tails are new traits. Rather, they were already present in the parent population but to only a tiny degree, and breeding develops and emphasizes these traits. But dogs and tame foxes can still breed with the original wolves and foxes because they are still the same species. Isolation and selection alone does not create new species. If it did then breeders would be creating new species all the time.
And THAT happens only when all the alleles for OTHER traits are suppressed, reduced, or eliminated = REDUCED GENETIC DIVERSITY REQUIRED TO FORM A NEW SPECIES.
Then why can't breeders create new species?
So? Should happen a lot in my scenario that you get new "species" from new mixes of old alleles.
No, it should not happen that a new species emerges by "new mixes of old alleles". If a subpopulation has all the same genes and alleles of the original population then these populations can still interbreed and are still the same species.
Plus your approach will never yield what we actually see in nature, which is that only very, very similar species have the same genes. Any species whose differences are more than slight will have different genes and alleles. Your conception will never produce different genes between species, which is precisely what we see in nature.
What we should see in nature were your view correct is a species heredity chart like this where the parent population has all the genes and alleles of all the daughter and grand-daughter populations while the daughter populations have only subsets of the parent's genes and alleles. And the grand-daughter populations should have subsets of the daughter populations' genes and alleles:
[face=Lucida Console]                                            parent pop
                                                |
                         --------------------------------------------------
                         |                                                |
                   daughter pop 1                                  daughter pop 2
                         |                                                |
          -------------------------------                 -------------------------------
          |                             |                 |                             |
  daughter pop 1a               daughter pop 1b    daughter pop 2a               daughter pop 2b[/face]
What you need to find in order to have evidence that your scenario is something that actually happens is to find that every gene and allele in the daughter populations is already present in the parent population. And you need to find that every gene and allele in the granddaughter populations is already present in the daughter and parent populations.
But something like this has never been found, not in nature and not in breeding programs.
If the only way to get a ceramic pot out of a hunk of clay is to pare away all the stuff that doesn't look like the ceramic pot, you aren't going to get the ceramic pot if you carve a little then add a little clay somewhere else and so on. Carve and add carve and add, no, that is not how it works in reality.
No, that's pretty much how it works in reality, except for the part about having the specific goal of a ceramic pot. Evolution has no specific goals, just the general goal of adaptation to the environment.
What you guys seem not to appreciate is that the existing alleles and genes in a genetically diverse population are more than sufficient to form many many subspecies through selection and isolation of portions of the gene pool.
Of course we understand that one can form many subspecies from a single set of genes and alleles. But one cannot form a new species unless one has a supply of new genes and alleles.
Main populations are evolving, too, and possibly at a faster rate since they can draw upon a much larger inflow of new mutations.
NOT UNLESS THERE IS SELECTION.
I think you must be operating under the misimpression that main populations do not undergo selection. That would be incorrect. The processes of mutation and selection are always in operation in all populations everywhere.
The new combinations are brought about by the change in gene frequencies brought about by the reproductive isolation of a reduced number of individuals, making for a new gene pool of interbreeding individuals, and that's how new breeds, varieties, species come about. The new combinations are powerful sources of new traits. You do not need mutations.
This would be incorrect. A subpopulation with all the same genes and a subset of the alleles will still be the same species. It will still be able to interbreed with the main population. You cannot create a new species without new genes and alleles.
Of course selection operates upon mutation. Always, constantly, all the time. How could it not? Selection operates on all expressed parts of the genome, whether newly arisen through mutation or part of the original genome.
You must be using the term "selection" in some other sense than I am. Selection is something that happens at the population level as I am using it.
What I said is true of both individuals and populations. Let me say it again in terms that are specific to a population. Selection operates continuously upon all expressed portions of the gene pool of a population, including newly expressed portions due to mutation.
That mutation and selection are always active is why both faucet and drain were open at the same time in the bathtub analogy.
Sounds plausible in the abstract but in reality it's not what happens, it does not describe what really occurs.
Again, we think this is what occurs in reality because when we looked at reality this is what we observed happening. We observed that almost all reproductive events include a small number of mutations. We observed that the environment is always exerting selection pressures on populations.
--Percy

This message is a reply to:
 Message 185 by Faith, posted 02-28-2013 11:00 AM Faith has not replied

Replies to this message:
 Message 194 by NoNukes, posted 03-01-2013 10:50 AM Percy has seen this message but not replied

  
Percy
Member
Posts: 22693
From: New Hampshire
Joined: 12-23-2000
Member Rating: 3.8


Message 239 of 1034 (692372)
03-02-2013 8:35 AM
Reply to: Message 234 by Faith
03-02-2013 2:48 AM


Re: Mutations Don't Add Anything That Could Rescue the ToE
Hi Faith,
I've been looking at these inverted nested quotes you've been including in your messages for some time now and finally have to comment:
quote:
but that even IF it increases beneficial diversity then it can't be always coming along to undo the processes of selection and isolation or you'll never get new varieties
The new diversity need not be of the same kind that is being subject to selection to create the species.

The top quote is you and the bottom quote is NoNukes, but in NoNukes original message it actually looked like this:
quote:
but that even IF it increases beneficial diversity then it can't be always coming along to undo the processes of selection and isolation or you'll never get new varieties
The new diversity need not be of the same kind that is being subject to selection to create the species.

So obviously you're manually creating the nested quotes. Did you know that when composing your message that if you click on the "Peek Mode" button of the message you're replying to (displayed a few inches below the message box where you're entering your message) then you'll see the raw text that created the quotes? Then you just cut-n-paste them into your message and add quote codes around them.
If you already know this but are quoting this way because you prefer it, then I'll just comment that for me it is confusing that your manner of quoting is backwards from the original and from the way everyone else is quoting.
--Percy

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

  
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