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Author Topic:   Molecular Population Genetics and Diversity through Mutation
Dr Adequate
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Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


Message 421 of 455 (786591)
06-23-2016 5:47 PM
Reply to: Message 420 by Faith
06-23-2016 4:28 PM


Re: Forgetful?
And your use of capital letters does nothing to prevent mutations from adding genetic diversity.
This message is a reply to:
 Message 420 by Faith, posted 06-23-2016 4:28 PM Faith has not yet responded

  
Faith
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Posts: 23978
Joined: 10-06-2001
Member Rating: 1.0


Message 422 of 455 (786596)
06-23-2016 6:14 PM
Reply to: Message 416 by Dr Adequate
06-23-2016 2:27 AM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
...which they aren't but anyway, it would only be true IF the reduction in genetic diversity was not necessary to make new species.

Uh, no.

In order for selection to take place, there needs to be a variety of genotypes to select from.

Of course.

Mutations supplies these.

Or they are built in from Creation.

The fact that selection is required to produce new species does not mean that mutation does not provide the variety that is selected from. Because why would it?

The fact that selection is required doesn't mean it couldn't be mutations that provide the variety, I just don't see that anybody has ever proved that to be the case. Hypothetically I grant that it COULD be true, I just don't believe it is, AND EVEN IF IT IS TRUE, it doesn't matter because the selective processes that bring about the new species will always reduce it and that will always be the overall trend of those processes and no amount of addition could do anything but muddy up the species.

Variation of phenotypes requires reduction of genetic variability.

That is a very odd collection of words.

It's nothing but the same argument I've been giving. To get new phenotypes, which is the kind of variation Darwin was talking about, not genetic diversity but phenotypic diversity, requires the loss of the genetic material that codes for other phenotypes than the selected ones. I CAN keep saying this even in the teeth of your refusal to understand it.

Darwin didn't realize that selection requires this reduction.

Darwin realized that selection was a selective process which selects for some variations and against others. This is why he called it selection. And ever since then, everyone who has undertaken even the most cursory study of evolution has understood it. I understand it. All the geneticists in the world understand it. Even you understand it.

What is not understood is that selecting for some variations and against others means the loss of the genotypes for the others. Nothing is added, only lost, in the selection of some variations over others.

What makes you unique is that you cannot also grasp what Darwin and I and all the geneticists everywhere can grasp: that if there is a constant supply of new variation, natural selection will never run out of variation to select from.

No, because natural selection is one of the subtractive processes that MUST reduce or eliminate a lot of that supply of variation in order to form a new species from some part of it. If you don't form species you may have lots of new variation, but then you aren't getting evolution. It's evolution I'm talking about, the formation of new species, which requires selection, which requires the loss of genetic material for unselected phenotypes.

Again, variation according to Darwin (and me) is the emergence of new phenotypes, it has nothing to do with adding genetic diversity.

If you can quote Darwin saying that or anything remotely like it, I shall eat my hat. But if, as I suspect, you are just making shit up, my hat will remain unscathed.

Darwin didn't know about genes or genetic diversity/variability, all he knew was the observed variation we all see: the different shell of the Galapagos tortoise, the different beaks of the finches, the pigeon variations he could produce himself by selecting for a particular trait. That these differences in phenotype require the loss of genetic material couldnt have been part of his theory. And this problem continues to plague the ToE today as you all actually seem to think that selection can just go on and on and on without cost, and once you see that there is some cost all you have to do is believe that mutations will save the day. Mostly though the cost isn't seen at all when evolutionary processes are described. What you really don't get is that it doesn't matter how much genetic diversity is in the main population of a species, when part of it is selected to bring out new traits toward the formation of a new variety or species, the great majority of the genetic diversity is left behind in the parent population, if it has enough numbers for that to be the case.

This is what was wrong with your "refutation" of my argument by the picture of all the dog breeds. Each of those breeds has only a small selected portion of the genetic diversity in the whole dog population, and it's the BREEDS that are "evolving," showing that evolution of new types requires that loss. It's in EACH breed that the argument is made. It's THERE that you see the formation of new phenotypes. It is THERE that evolution is going on. It really matters not one whit what the source of the genetic diversity is from which the breed is selected, to GET the breed means losing it or leaving it all behind. From what's left behind you may get lots of other breeds, and each breed demonstrates the same point: that selection requires reduction or loss. Since this is where evolution is actually going on it should be easy to see that eventually it could lead to complete genetic depletion and in any case CAN'T lead to the necessary genetic diversity for evolution to continue.. But then you want to add mutations and destroy those breeds? But then you don't have the platform for further evolution, you're back at Square One.

I've tried many times to create a graphic representation of this. I always find some way I'm misrepresenting what I want to represent and have to start over. And Paint is a klutzy medium which makes representing sufficient numbers to get across the point especially difficult.

I really truly can't believe you are this dense.

I am indeed not dense. Nor are all the geneticists in the world. Indeed, if you thought about it for a moment you might begin to suspect that if anyone is being dense, it's the woman who disagrees with all the geneticists about genetics while being repeatedly unable to define such fundamental terms as "mutation".

A mutation is a mistake in DNA replication. The vast majority of mutations are deleterious; there is a vast number of genetic diseases brought about by mutations. There is also a vast number of mutations that apparently do nothing to the phenotypic result of the change in the DNA and are called "neutral." Very very small numbers of mutations do anything at all useful to the organism. This information comes from the geneticists, not from me.

The problem is that geneticists, biologists, geologists etc. all subscribe to the ToE and always think according to its principles no matter how false and misleading they are. This gives you all a certain denseness when it comes to thinking outside the box.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 416 by Dr Adequate, posted 06-23-2016 2:27 AM Dr Adequate has responded

Replies to this message:
 Message 423 by Dr Adequate, posted 06-23-2016 6:42 PM Faith has responded
 Message 430 by Meddle, posted 06-23-2016 10:09 PM Faith has not yet responded

    
Dr Adequate
Member
Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(1)
Message 423 of 455 (786598)
06-23-2016 6:42 PM
Reply to: Message 422 by Faith
06-23-2016 6:14 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
Or they are built in from Creation.

Well, we can see mutations occurring.

The fact that selection is required doesn't mean it couldn't be mutations that provide the variety ...

Thank you.

AND EVEN IF IT IS TRUE, it doesn't matter because the selective processes that bring about the new species will always reduce it and that will always be the overall trend of those processes ...

Well, show your working.

You admit now that there are two processes, one of which adds diversity, the other of which subtracts it. If you maintain that there must be some tendency for the latter to win (contrary to reason and observation) then you are obliged to demonstrate and not merely assert this.

What is not understood is that selecting for some variations and against others means the loss of the genotypes for the others. Nothing is added, only lost, in the selection of some variations over others.

That is plainly understood. I understand it. All geneticists understand it. Everyone who knows what the word "selection" means understands it. Even you understand it.

What makes you unique is not that you (like everyone else) understand the role of selection but that you (unlike everyone else) do not understand the role of variation.

his is what was wrong with your "refutation" of my argument by the picture of all the dog breeds. Each of those breeds has only a small selected portion of the genetic diversity in the whole dog population, and it's the BREEDS that are "evolving," showing that evolution of new types requires that loss. It's in EACH breed that the argument is made. It's THERE that you see the formation of new phenotypes. It is THERE that evolution is going on. It really matters not one whit what the source of the genetic diversity is from which the breed is selected ...

Thank you. Very well then. If you can imagine evolution of all those breeds from a couple of wolves front-loaded with variation, then you can also imagine a subpopulation of dogs acquiring that much variation again through mutation, and so giving rise to as many new breeds. And the process need never stop.

But then you want to add mutations and destroy those breeds? But then you don't have the platform for further evolution, you're back at Square One.

Well, that's a funny way of putting it? Is the human species "destroyed" by having many races? Are chihuahuas "destroyed" by having all those different colors and patterns? Is Canis lupus "destroyed" by exhibiting the genotypes for all those breeds?

(The odd thing is, of course, that if you think that genetic diversity "destroys" a species, then since you also think that God front-loaded the diversity, you must conclude that God created "destroyed" species to start with, and that we would undestroy them by extirpating the genetic diversity.)

I've tried many times to create a graphic representation of this. I always find some way I'm misrepresenting what I want to represent and have to start over. And Paint is a klutzy medium which makes representing sufficient numbers to get across the point especially difficult.

Well of course you can't represent it. Your words don't correspond to anything concrete, or even to something that could be given a concrete representation.

The problem is that geneticists, biologists, geologists etc. all subscribe to the ToE and always think according to its principles no matter how false and misleading they are. This gives you all a certain denseness when it comes to thinking outside the box.

The "box" is the known facts of genetics.


This message is a reply to:
 Message 422 by Faith, posted 06-23-2016 6:14 PM Faith has responded

Replies to this message:
 Message 427 by Faith, posted 06-23-2016 8:12 PM Dr Adequate has responded

  
Faith
Member
Posts: 23978
Joined: 10-06-2001
Member Rating: 1.0


(1)
Message 424 of 455 (786602)
06-23-2016 7:30 PM


An attempt at a simple illustration
I haven't been able to find a way to represent the argument in some complexity, but it occurred to me maybe a very simple example might work better:

Say you select for the white flower, or bb. You grow hundreds of white flowers. There will be no pink flowers in your planting, no B's. no BB's or Bb's. You're aware that if you select a pink flower you may also get white flowers, but selecting the white flower gets you only white flowers. But let's assume you don't know anything about the genetics, you just know you selected the white flower and were able to grow only white flowers.

In a certain sense wouldn't you think you had evolved them? Isn't this what Darwin did with his pigeons, which led him to the principle of natural selection as the mechanism of evolution?

So now let's say you examine your white flowers and decide to see if there is another variation you can exploit, perhaps a tinge of color, and you find that some have a pale blue tinge near the stem so you select those; and among those you choose the larger flower as well. So you select for these small differences you find, and you discover you can indeed get a larger white flower with a tinge of blue near the stem. In fact you can keep selecting for the same traits, leaving out the weaker expressions of the selected trait and always choosing the stronger expressions. Assuming this is genetically possible you could eventually get a much larger flower than the originals, all with a striking blue near the stem.

So you've eliminated all the pink versions. Now you've eliminated all the pure white versions and all the smaller versions and got large white flowers with a blue center. Which you got by LOSING all the other versions you rejected. Your new flower has NO B alleles, no small size alleles, and no pure white alleles. You've probably got homozygosity for all those traits you selected. Perhaps you've even reached the point where cross-pollination has become genetically impossible between your new variety and those it evolved from.

What's happened? You've LOST genetic diversity by producing a new variety or species.

If cross-pollination is still possible you may be able to get it back. But then you will no longer have your large white flower with the blue center will you? All that change you worked to get is gone. All that evolution is gone. But you have all the genetic diversity you could want. And if mutations are also contributing to that diversity a lot more. But you don't have your new flower, your new variety.

Darwin's pigeons with the exaggerated traits he'd selected were still able to mate with the wild types and eventually the offspring reverted to that wild type. He lost his new pigeon types but got back his genetic diversity, though of course he didn't think in genetic terms. But if they had become genetically unable to mate with the wild types he'd have had a new species of pigeon, right? At the cost of all the traits in the wild type. It's an either/or: either you get the new variety with low genetic diversity or you lose the new variety in exchange for high genetic diversity. (It's possible after all your experimentation that you wouldn't get the original varieties back but some new combination of traits.)

Edited by Faith, : change stranger to stronger


Replies to this message:
 Message 425 by Dr Adequate, posted 06-23-2016 7:40 PM Faith has not yet responded
 Message 426 by NoNukes, posted 06-23-2016 7:48 PM Faith has not yet responded
 Message 434 by herebedragons, posted 06-23-2016 11:01 PM Faith has responded
 Message 436 by PaulK, posted 06-24-2016 12:53 AM Faith has responded

    
Dr Adequate
Member
Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(3)
Message 425 of 455 (786603)
06-23-2016 7:40 PM
Reply to: Message 424 by Faith
06-23-2016 7:30 PM


Re: An attempt at a simple illustration
And if mutations are also contributing to that diversity a lot more. But you don't have your new flower, your new variety.

If so many mutations arose and were fixed that we would say that the variety had turned into a completely new variety, that would be an example of evolution.

What can I say? Your point seems to be that mutations will keep evolution going; and that if evolution keeps going, then it won't stop at any particular point. Which is kinda what I've been trying to tell you.


This message is a reply to:
 Message 424 by Faith, posted 06-23-2016 7:30 PM Faith has not yet responded

  
NoNukes
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Posts: 9324
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.6


Message 426 of 455 (786604)
06-23-2016 7:48 PM
Reply to: Message 424 by Faith
06-23-2016 7:30 PM


Re: An attempt at a simple illustration
But let's assume you don't know anything about the genetics

Interesting.

In a certain sense wouldn't you think you had evolved them?

I think your mistake here is to assume that Darwin being right or wrong about a specific case means anything at all? Let's assume that Darwin completely missed the boat regarding those pigeons. How would that lesson apply to the evolution of moths in a situation where we know exactly why there are black and white moths. We know to a high degree of certainty that there were no black moths prior to a mutation appearing.

And of course we do know about genetics.

But let's consider Darwin's observation. And a simple case of recessive vs dominant genes. How would Darwin have missed the fact that one fourth of the pigeons already had those traits? I believe your sup

So now let's say you examine your white flowers and decide to see if there is another variation you can exploit

Is this a new trait or one that we simply failed to see in the past?

So you've eliminated all the pink versions. Now you've eliminated all the pure white versions and all the smaller versions and got large white flowers with a blue center.

Have you eliminated all of the pink versions in the entire world, or just in your current population? Is the result of what you have created a new species or just a new variety of the original species? If it is a new species, under what definition is the new color not simply a variant of the old? Is it simply "because Faith says it is a new species"? Why can we not have a later mutation that changes the color of the stamen in the flowers where that change propagates to be about 1/4th of the population? Do you believe that every trait gets selected for our against?

I think your example might be helpful in giving people a place to describe their objections, but I don't believe it proves your point.

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

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This message is a reply to:
 Message 424 by Faith, posted 06-23-2016 7:30 PM Faith has not yet responded

    
Faith
Member
Posts: 23978
Joined: 10-06-2001
Member Rating: 1.0


Message 427 of 455 (786605)
06-23-2016 8:12 PM
Reply to: Message 423 by Dr Adequate
06-23-2016 6:42 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
AND EVEN IF IT IS TRUE, it doesn't matter because the selective processes that bring about the new species will always reduce it and that will always be the overall trend of those processes ...

Well, show your working.

I'll try to elaborate on the illustration I just gave later.

You admit now that there are two processes, one of which adds diversity, the other of which subtracts it.

I've never denied it.

If you maintain that there must be some tendency for the latter to win (contrary to reason and observation) then you are obliged to demonstrate and not merely assert this.

It's not a matter of "winning," it's that you can ONLY get a new breed or variety or species by subtracting, and if instead you add you will lose the breed or variety or species. That is indicated in my discussion of that illustration.

This is what was wrong with your "refutation" of my argument by the picture of all the dog breeds. Each of those breeds has only a small selected portion of the genetic diversity in the whole dog population, and it's the BREEDS that are "evolving," showing that evolution of new types requires that loss. It's in EACH breed that the argument is made. It's THERE that you see the formation of new phenotypes. It is THERE that evolution is going on. It really matters not one whit what the source of the genetic diversity is from which the breed is selected ...

Thank you. Very well then. If you can imagine evolution of all those breeds from a couple of wolves front-loaded with variation, then you can also imagine a subpopulation of dogs acquiring that much variation again through mutation, and so giving rise to as many new breeds. And the process need never stop.

Do you picture evolution as a process of making breeds/species and losing them then? Isn't it supposed to proceed by building upon what's already been established? If you add mutations you aren't building, you are losing the species you already had. If those mutations are SELECTED -- meaning you lose some to get yet a new set of phenotypes-- then you could get yet a new species. But it will be by losing the unselected traits as usual. You will have an overall loss of genetic diversity AGAIN, for this NEW species. You can get it back by mutations or gene flow if that is still possible, but then you'll just go through exactly the same sequence again if you are to arrive at yet another new species. This is a simplified description of what REALLY happens; it bears no resemblance to what the ToE is always presented as doing. "What's to stop microevolution from just continuing" is the usual query of the Evo, often repeated here at EvC. They aren't thinking of reduction of genetic diversity at all, of loss at all, they are imagining what they've always understood the ToE describes, the endless continuation of variation without a hitch or a glitch. No genetic cost, just onward and upward from species to species to species. Just as Darwin imagined.
'

But then you want to add mutations and destroy those breeds? But then you don't have the platform for further evolution, you're back at Square One.

Well, that's a funny way of putting it? Is the human species "destroyed" by having many races? Are chihuahuas "destroyed" by having all those different colors and patterns? Is Canis lupus "destroyed" by exhibiting the genotypes for all those breeds?

Mutations don't add "many races," they just change the existing race or breed or variety etc. The human species is not destroyed in any case, but a particular race of human beings would be lost if it completely mingled with another race or acquired enough mutations to change recognizably over time. That's what I mean. Chihuahuas don't stop being chihuahuas because of their many subtypes, but if they're all bred with cocker spaniels or allowed to mate with mongrels and reproductive isolation is not maintained then the chihuahua breed would no longer exist. Same if mutations kept changing them. (Canis lupus, by the way, doesn't "exhibit" the genotypes for all those breeds, those genotypes are the result of new gene frequencies brought about by selection. The breeds that emerge are not programmed into the Dog Kind somehow, they are the result of new genetic combinations. There must be hundreds of potential other kinds of dog breeds in the original Dog pool, that could have emerged instead of the ones we have, or if death had never entered Creation might still be able to have.)

(The odd thing is, of course, that if you think that genetic diversity "destroys" a species, then since you also think that God front-loaded the diversity, you must conclude that God created "destroyed" species to start with, and that we would undestroy them by extirpating the genetic diversity.)

It's ADDING genetic diversity when you already have a breed or variety or species that destroys that breed or variety or species. The original diversity is the necessary pool of variation from which new species are selected, but when the combination that makes a new species is selected from that pool, you have the species but have left the diversity behind --where it can still be the pool from which new breeds or varieties can be selected, (assuming there is still enough genetic diversity for that -- because of course after many subspecies have been formed eventually the original pool is also depleted.)

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 423 by Dr Adequate, posted 06-23-2016 6:42 PM Dr Adequate has responded

Replies to this message:
 Message 428 by Dr Adequate, posted 06-23-2016 9:30 PM Faith has responded

    
Dr Adequate
Member
Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(1)
Message 428 of 455 (786606)
06-23-2016 9:30 PM
Reply to: Message 427 by Faith
06-23-2016 8:12 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
It's not a matter of "winning," it's that you can ONLY get a new breed or variety or species by subtracting, and if instead you add you will lose the breed or variety or species.

And yet the human race have not been "lost" by the acquisition of different colors.

Do you picture evolution as a process of making breeds/species and losing them then? Isn't it supposed to proceed by building upon what's already been established? If you add mutations you aren't building, you are losing the species you already had.

No, you are increasing the variety of the species. Which is evolution. If selection then picks out these new varieties and fixes them, replacing the old ones, this may go so far as to produce a completely different species. Which is evolution. Or if this only happens in an isolated population of the species, then you get a new species and keep the old one. Which is evolution.

Again, your point seems to now be that yes, mutation happens, and yes, that means that evolution will never stop --- but that you consider this to be a bad thing. I can really make no more of your argument.

Mutations don't add "many races," they just change the existing race or breed or variety etc.

That depends on whether they go on to be fixed in the species.

They aren't thinking of reduction of genetic diversity at all, of loss at all ...

Yes they are. They are aware of natural selection. I am aware of natural selection. All geneticists are aware of natural selection. Darwin was aware of natural selection. Everyone who was paying attention during biology is aware of natural selection. Even you are aware of natural selection.

What makes you different from us is not that you (like us) are able to grasp the role that natural selection plays in evolution, but that you (unlike us) are unable to grasp the role that variation plays in evolution.

It's ADDING genetic diversity when you already have a breed or variety or species that destroys that breed or variety or species.

But why does it matter where the diversity comes from? If a species is to be considered "destroyed" when it has a certain amount of diversity, then why does it matter whether the diversity that "destroys" it comes from God or from observable natural processes?

Incidentally, can you tell us how much diversity does destroy a species?

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 427 by Faith, posted 06-23-2016 8:12 PM Faith has responded

Replies to this message:
 Message 431 by Faith, posted 06-23-2016 10:18 PM Dr Adequate has responded

  
Dr Adequate
Member
Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(4)
Message 429 of 455 (786607)
06-23-2016 9:44 PM


Graphical Representation
Here is a graphical representation. It is, of course, schematic: for example, real viable populations are bigger.

Note that when we stop the music, we have no organism that is identical with any member of the original population. If you like, you may say it has been "lost". Yeah, that's 'cos evolution has happened.

Note also that neither population, still less the clade as a whole, has decreased in variation, 'cos why would they? They could, but you have yet to produce a reason why they should.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


Replies to this message:
 Message 432 by Faith, posted 06-23-2016 10:23 PM Dr Adequate has responded

  
Meddle
Member
Posts: 156
From: Scotland
Joined: 05-08-2006


(1)
Message 430 of 455 (786609)
06-23-2016 10:09 PM
Reply to: Message 422 by Faith
06-23-2016 6:14 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
No, because natural selection is one of the subtractive processes that MUST reduce or eliminate a lot of that supply of variation in order to form a new species from some part of it. If you don't form species you may have lots of new variation, but then you aren't getting evolution. It's evolution I'm talking about, the formation of new species, which requires selection, which requires the loss of genetic material for unselected phenotypes.

It goes without saying that natural selection is a subtractive, but this process is ongoing, it does not stop when a new species forms. This is because the selective forces which first shaped this species are still acting on the individuals in the population. This is one reason why it is incorrect to suggest that you canít form a new species, or even prevent evolution, if you have processes which can increase genetic variation.

To understand this think of a population which has adapted to exist within a stable ecosystem. In this case alleles that are positively selected, whether they come from the previous generation or are newly created by mutation, are those which allow an individual to successfully compete with others of its species. So in this scenario the increased diversity from mutation is offset by selection to maintain the expected phenotype of that species. To put it another way, evolution here acts as a conservative force, maintaining the species.

However, ecosystems do not remain stable and so the selective pressures on a species can change over time, and so alleles that were positively selected before may no longer be advantageous. This also means some alleles that were nearly neutral becoming positively selected for. If this is environmental change this could result in a shift in the phenotype of the population as a whole, meaning we would have to change the way we described that species. Or it may be a more limited change on the edge of a populations range, where the selective pressures vary from the pressures affecting the main population, so we define subpopulations.

Of course Founder effect is another example you highlighted, as would another example being mass extinction. In these cases the population may find itself in an environment where there is very little competition from other species, so more mutations may become positively selected as they allow individuals to exploit alternative niches instead of directly competing with the parent population, leading to diversification and speciation.


This message is a reply to:
 Message 422 by Faith, posted 06-23-2016 6:14 PM Faith has not yet responded

  
Faith
Member
Posts: 23978
Joined: 10-06-2001
Member Rating: 1.0


Message 431 of 455 (786610)
06-23-2016 10:18 PM
Reply to: Message 428 by Dr Adequate
06-23-2016 9:30 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
It's not a matter of "winning," it's that you can ONLY get a new breed or variety or species by subtracting, and if instead you add you will lose the breed or variety or species.

And yet the human race have not been "lost" by the acquisition of different colors.

I do not understand how you are misconstruing what I wrote about losing the breed. The whole human race is not a breed or a variety, or even a race as the term is usually used. I've never said the whole Kind would be lost, just the breed or variety or species or race. And all I mean by lost is that its recognizable character, its specific traits, have been altered so that if enough change occurs it is eventually not the same breed. I'm not saying that the Kind of which it is a subvariety or subspecies has lost anything. All these subpopulations are characterized by a constellation of traits: a race is not merely a different color, it's a complete design unto itself, as is a breed or a variety etc etc etc Nothing is lost to humankind by acquiring different colors, meaning different races; and the design of a particular dog breed does not lose anything for the Dog Kind as a whole. I really can't figure out how you could read me as saying such a thing.

Do you picture evolution as a process of making breeds/species and losing them then? Isn't it supposed to proceed by building upon what's already been established? If you add mutations you aren't building, you are losing the species you already had.

No, you are increasing the variety of the species. Which is evolution.

Not if the mutations change the basic characteristics of the species so that it is no longer recognizable as that species. The many chihuahuas are still recognizable as chihuahuas by their size and basic body structure. And there is no reason to suppose that the differences are the product of mutations either.

If selection then picks out these new varieties and fixes them, replacing the old ones, this may go so far as to produce a completely different species. Which is evolution.

But when that happens the alleles for the traits for the varieties being replaced are getting reduced and can eventually be lost altogether. Yes you may get your new species, and yes that is evolution, but the only way you can get it is if the genetic underpinnings of the rejected traits are lost. Which I just explained in my last post. You can get a series of species by adding and subtracting but it's an either/or: you can have the species or you can have the genetic diversity. The species has to lose genetic diversity to become a species, and additional genetic diversity can only alter the species you have, which is what I mean by destroying it. Take your pick. Do you want evolution -- the formation of species which requires reduced genetic diversity -- or do you want high genetic diversity which changes the species? You can have high genetic diversity with scattered phenotypes in a population, which isn't a species, or you can have the formation of a new species through loss of genetic diversity. I believe all this is well enough illustrated in my example of the white flower.

Or if this only happens in an isolated population of the species, in which case you get a new species and keep the old one. Which is evolution.

Yes you can keep both, why not? But each requires the loss of genetic diversity, of the alleles for the traits it had to get rid of to develop those that characterize it. There's no way to get around that.

Again, your point seems to now be that yes, mutation happens, and yes, that means that evolution will never stop --- but that you consider this to be a bad thing. I can really make no more of your argument.

No, I say mutations themselves stop the processes of evolution that form new species, I certainly haven't said that mutations mean evolution will never stop, because evolution requires selection which always reduces genetic diversity. If you add diversity after you have a new species as a result of evolution/selection/reduction of genetic diversity, you simply lose your species. It's no longer the same species. You may get something else, even another species eventually, but you'll have lost the species originally selected. This isn't evolution, this is just adding and subtracting to no particular purpose. If you do get a species in the end it will be only because it's lost competing alleles for its collection of traits. And then you'll be alarmed again to realize that it HAS lost genetic diversity and want to get it back and around we go.

[qs]

Mutations don't add "many races," they just change the existing race or breed or variety etc.

That depends on whether they go on to be fixed in the species.

Too tired to continue. Have to come back to this.


This message is a reply to:
 Message 428 by Dr Adequate, posted 06-23-2016 9:30 PM Dr Adequate has responded

Replies to this message:
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Faith
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Posts: 23978
Joined: 10-06-2001
Member Rating: 1.0


Message 432 of 455 (786611)
06-23-2016 10:23 PM
Reply to: Message 429 by Dr Adequate
06-23-2016 9:44 PM


Re: Graphical Representation
I've many times tried to construct a similar graphic representation. It doesn't work. Yours is basically undecipherable. An interesting attempt though. But I'll have to come back to it.
This message is a reply to:
 Message 429 by Dr Adequate, posted 06-23-2016 9:44 PM Dr Adequate has responded

Replies to this message:
 Message 433 by Dr Adequate, posted 06-23-2016 10:56 PM Faith has not yet responded

    
Dr Adequate
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Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(3)
Message 433 of 455 (786612)
06-23-2016 10:56 PM
Reply to: Message 432 by Faith
06-23-2016 10:23 PM


Re: Graphical Representation
Yours is basically undecipherable.

Does anyone else on this thread have any problem understanding it?

No? Just Faith?

What don't you understand, Faith?

I've many times tried to construct a similar graphic representation. It doesn't work.

I think I can do it. Yours would look like this:

But since mutation exists, there is no likelihood, let alone a necessity, that anything like that would actually take place.


This message is a reply to:
 Message 432 by Faith, posted 06-23-2016 10:23 PM Faith has not yet responded

  
herebedragons
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Posts: 1251
From: Michigan
Joined: 11-22-2009
Member Rating: 5.6


Message 434 of 455 (786613)
06-23-2016 11:01 PM
Reply to: Message 424 by Faith
06-23-2016 7:30 PM


Re: An attempt at a simple illustration
So you've eliminated all the pink versions. Now you've eliminated all the pure white versions and all the smaller versions and got large white flowers with a blue center. Which you got by LOSING all the other versions you rejected. Your new flower has NO B alleles, no small size alleles, and no pure white alleles. You've probably got homozygosity for all those traits you selected. Perhaps you've even reached the point where cross-pollination has become genetically impossible between your new variety and those it evolved from.

What's happened? You've LOST genetic diversity by producing a new variety or species.

Or... you now have a population of plants with pink flowers AND a population of plants with white flowers AND a population with large white flowers with a blue center. So you may have lost the pink allele in the white-flowered version, but that doesn't mean the pink allele is lost completely. And if they won't cross breed, you now have three separate species that originated from a common ancestor by descent with modification.

Faith writes:

Chihuahuas don't stop being chihuahuas because of their many subtypes, but if they're all bred with cocker spaniels or allowed to mate with mongrels and reproductive isolation is not maintained then the chihuahua breed would no longer exist. Same if mutations kept changing them.

Well, if ALL Chihuahuas bred with cocker spaniels, then yes, the Chihuahua breed would no longer exist. But what if only the Chihuahuas in Southern California were bred with cocker spaniels but the Chihuahuas in the rest of the world were not bred with cocker spaniels, the breed would not be lost.

But if they had become genetically unable to mate with the wild types he'd have had a new species of pigeon, right? At the cost of all the traits in the wild type. It's an either/or: either you get the new variety with low genetic diversity or you lose the new variety in exchange for high genetic diversity.

But there are still wild pigeons, right? And why do you consider losing the "wild" traits to be a "cost?" The point is that the traits in the new pigeon "species" were favored for some reason and so they were selected for. Yes, you have lost some traits in your new pigeon breed, but now you have a pigeon that is "better" than the wild breed.

While it may be true that diversity has decreased from the wild type to the new breed, there is no reason that variation can't increase in the new breed due to new mutations. Of course if those mutations are undesirable, they will be unlikely to make it into the next generations. However, if they are neutral or of minimal effect they can continue to accumulate until the next selection event, where a desirable trait emerges (such as a blue center in a flower, a flatter, shorter snout in a bulldog, or a peculiar color in the pigeon feathers), and now there will be the wild-type, the first breed and a new breed.

Honestly, this is beginning to sound like a slightly more sophisticated version of the "If humans evolved from monkeys then why are there still monkeys?" argument coupled with the no new genetic information argument.

HBD


Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

"Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.

Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.


This message is a reply to:
 Message 424 by Faith, posted 06-23-2016 7:30 PM Faith has responded

Replies to this message:
 Message 442 by Faith, posted 06-24-2016 12:53 PM herebedragons has responded

  
Dr Adequate
Member
Posts: 15475
Joined: 07-20-2006
Member Rating: 3.9


(2)
Message 435 of 455 (786615)
06-23-2016 11:26 PM
Reply to: Message 431 by Faith
06-23-2016 10:18 PM


Re: Once again now, evolution of new phenotypes REQUIRES loss of genetic diversity
I do not understand how you are misconstruing what I wrote about losing the breed. The whole human race is not a breed or a variety, or even a race as the term is usually used.

No, it's a species.

I've never said the whole Kind would be lost, just the breed or variety or species or race.

See? You say that species will be lost as a result of genetic diversity. And yet our species, Homo sapiens, comes in a range of shapes, sizes, and colors, and yet there is no sense in which our species is "lost".

Not if the mutations change the basic characteristics of the species so that it is no longer recognizable as that species.

Which would be evolution.

Again, your objection seems to be: "But if, as you say, evolution takes place, then this would result in evolution taking place!"

Well ... yes?

But when that happens the alleles for the traits for the varieties being replaced are getting reduced and can eventually be lost altogether.

Yes, that's what "fixed" means. That's exactly the scenario I'm proposing.

Yes you may get your new species, and yes that is evolution, but the only way you can get it is if the genetic underpinnings of the rejected traits are lost.

And replaced with the new traits which (by hypothesis) were produced by mutation. So there's no net loss of diversity over the whole process.

If you have an apple, and I give you an orange, and then take away your apple, have you undergone a net loss of pieces of fruit?

No, I say mutations themselves stop the processes of evolution that form new species, I certainly haven't said that mutations mean evolution will never stop, because evolution requires selection which always reduces genetic diversity. If you add diversity after you have a new species as a result of evolution/selection/reduction of genetic diversity, you simply lose your species. It's no longer the same species. You may get something else, even another species eventually, but you'll have lost the species originally selected. This isn't evolution ...

Yes it is, Faith. That is, exactly, evolution. If, for example, you start of with a population of Australopithecus and end up with a population of Homo sapiens, then evolution has taken place. Sure, you've lost the species you started with. But you've gained a new one which has evolved from the old one. If this is not evolution, then what is?

Edited by Dr Adequate, : No reason given.


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