If the diversity increases to any great extent you are going to lose your variety or breed. Where's the evidence that it increases to such an extent? Breeders aren't always having to contend with new traits after a breed is established. 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, and they don't have to be mutations either, they may be just the result of combinations of preexisting alleles brought about by the usual processes of sexual recombination. 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.
Re: Ring Species -- Greenish Warbler -- and Genetic Diversity
The gene pool contains all the alleles for all the variations, no increase is needed.
Of course, since that is the definition of gene pool. What you are ignoring is that each generation adds new mutations to the gene pool, mutations that didn't exist in the previous generations.
If you want to think they were created by mutations, I'll tolerate that idea up to a point, but it would be silly to think a brand new mutation is always going to be selected as the basis of a new phenotype when the gene pool is full of alleles for all kinds of variations anyway.
It is equally silly to think that no mutation can lead to a change in phenotype. The genetic differences between humans and chimps explain the morphological and physiological differences between humans and chimps. Quite obviously, mutations can change phenotype.
When a new smaller population splits off the idea is that it contains a different mix of alleles than the mother population had and those that dominate in the new will be different than those in the old and that's what brings about a new phenotype.
It also contains population specific mutations that accumulate after the two populations separate. This is an increase in genetic diversity.
The alleles already exist, Taq, whether they were created by mutation or built in at the beginning.
The alleles did not exist prior to the mutation.
Why are you guys always assuming you need new ones?
Go to my thread on antibiotic resistance and I will show you. We have also discussed the evidence for the mutations leading to the dark fur allele in pocket mice.
If you're right and mutation is the source of alleles, then I guess you'll get some new ones but there's no guarantee the newer mutations will be selected anyway, why should they be?
If the mutation leads to a beneficial adaptation, why shouldn't it be selected for? For example, a mutation that produces darker fur that offers superior camouflage in dark lava fields.
Sure. But I have no doubt there are already Bs and Cs and all the rest in the gene pool to begin with.
They clearly show evidence that the dark allele was not part of the ancestral gene pool, and that the mutations appeared after the dark lava fields appeared. This is based both on selection pressures on the dark allele and on sequence variation of the m1cr alleles. You had an ancestral gene pool without the dark allele. You then had volacanic eruptions producing fields of dark lava. You then had the appearance of mutations that produced dark fur. These mutations were then selected for in populations living on the black lava.
Re: Ring Species -- Greenish Warbler -- and Genetic Diversity
"Removes diversity overall?" Where are you getting that? I'm talking about how diversity is REDUCED (sometimes eliminated but ALWAYS reduced) by the fact that alleles that don't contribute to the new phenotype simply are not present in that gene pool or the phenotype would not develop.
Well, yes. And rivers run down to the sea.
Evolution requires a reduction of genetic diversity at a certain point, just as the process of walking requires that the right foot should stay still at a certain point, and the water cycle requires that some water should flow from the sea to the land.
Now, if someone points out that in constructing your argument you are ignoring known processes, it does not make that a strawman argument for you to point out that you know perfectly well that those processes exist, but that for the purposes of your argument you are ignoring them.
A: John Smith is guilty of this crime.
B: Prove it.
A: OK, he had a very strong motive.
B: But he has a completely airtight alibi. At the point when we know the crime was committed, we also know that he was a thousand miles away addressing an audience of a hundred policeman, all of them willing to testify that he was present. Your argument ignores that.
A: Strawman! Strawman! I know perfectly well that his alibi proves him innocent. Do you think I'm stupid?
B: So in that case, why do you say that he's guilty of the crime?
A: Because he had a very strong motive.
B: But you are ignoring the fact that all the objective evidence shows that he's innocent.
A: Strawman! Strawman! I have said that all the objective evidence shows that he's innocent. I'm not even talking about that. Why do you even keep mentioning it? I'm talking about my proof that he's guilty.
but I certainly know more than YOU with your ridiculous misrepresentation of my argument.
What argument? When are you going to get around to presenting something based on more than assertion?
In your most recent posts, you've suggest that all alleles are already present and that evolution is simply just getting some already present variation to come to the fore.
That suggestion is complete nonsense. You cannot back it up with anything but assertion, and yet it turns out to be the entire basis for your position. The truth is that evolution and selection work on both already present and new diversity. If you want to deny that then do the work involve with arguing against that proposition.
But you haven't and you won't. Yet somehow the fact that you don't have a case is everyone else's fault and not your own.
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)
The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison.
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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.
True. And to move the left foot by walking, the right foot has to stay in the same place.
But this is not an argument that the right foot always stays in the same place, and that progress by walking is impossible.
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?
The variation is BUILT IN to the genome it does not need to be ADDED.
Then why did mutations have to occur in the mc1r gene in pocket mice in order to get mice with dark fur?
They clearly show evidence that the dark allele was not part of the ancestral gene pool,
What IS the evidence for that? I cant read the whole article right now but skimmed the first part and don't see how it's so certain that a mutation was involved.
and that the mutations appeared after the dark lava field appeared.
Again this sounds awfully teleological. What would cause the mutation to appear with such uncanny timing? Why isn't it a random event as I thought mutations usually are? And again how exactly do you KNOW this was a recent mutation anyway?
Why couldn't it be a regularly occuring recessive allele in the gene pool that got selected because the light mice now get decimated by predators? They eat some light mice, the survivors continue to reproduce but now the recessives pair up more predictably, bringing out the darker fur here and there, they get selected because it's only the light mice that continue to get eaten and so on and so forth.
This is based both on selection pressures on the dark allele
which would also be the case if the dark allele were a regularly occurring but recessive variation.
and on sequence variation of the m1cr alleles. You had an ancestral gene pool without the dark allele.
You know this absolutely for sure?
You then had volacanic eruptions producing fields of dark lava. You then had the appearance of mutations that produced dark fur.
Again how do you explain such a miraculously fortuitous occurrence according to the principle of randomness I thought was standard?
These mutations were then selected for in populations living on the black lava.
That part is easy to understand, that would also be the case if the allele were ancestral. It's the part about the dark fur just showing up like the cavalry when needed that's hard to fathom.
Dunno, the whole thing's a great mystery to me as you present it, redolent of miracle and magic.
If mutations are now understood to show up on cue when needed it sounds to me like a whole new theory is needed here.
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.