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Author Topic:   Peter & Rosemary Grant, Darwin's Finches and Evolution
NoNukes
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Posts: 9428
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.8


Message 91 of 131 (725903)
05-03-2014 12:31 PM
Reply to: Message 90 by PaulK
05-03-2014 5:20 AM


Re: I hope this is clarifying
"choosing to blind yourself"

Thanks for giving me something to consider because I had reached the conclusion that Faith was simply lying. She now says she is not interested in the process for forming breeds, despite her position that evolution is just like breeding. That's kind of goal post shifting is too tiresome to bother with at 2:00 AM, for me anyway.

At this point I think it is pretty clear that Faith has no argument that has not been refuted in other threads, and that her claims of being misunderstood are without substance. But perhaps you are right and she isn't quite the dishonorable person I thought she was.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

I have never met a man so ignorant that I couldn't learn something from him. Galileo Galilei

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


This message is a reply to:
 Message 90 by PaulK, posted 05-03-2014 5:20 AM PaulK has not yet responded

    
Faith
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Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 92 of 131 (725962)
05-05-2014 3:46 AM
Reply to: Message 90 by PaulK
05-03-2014 5:20 AM


Re: I hope this is clarifying
I do think that anyone who thinks THROUGH what I'm saying should come to see it as I do. What happens to the genetic increases is hard to describe clearly. I might be able to illustrate it but I don't think that would be particularly clear either. But let me try to describe what I'm seeing.

So you have a population of some species in the wild, say a fairly large number, say pack or herd animals so we can count on them all breeding together and not isolating themselves in families like the rabbits discussed some time back.

So what is happening in this population? Genetic changes are occurring from time to time. You attribute these to mutations, I attribute them to simple sexual recombination of existing alleles. Of course I'm sure you include this in your scenario too, we are merely disagreeing about the source of the genetic material.

So these genetic changes are occurring. Say they ARE mutations in single individuals. How many of these occur in the germ cells? Anyway it's only those that will get passed on of course. And only the neutral and the "beneficial" ones if we assume the bad ones will be selected out. And as you've all pretty much agreed, this can take a very long time. If mutations could save the cheetah it will be a very long time if they can hold out that long. Anyway...

So after a generation or two the genetic changes start to show up in the phenotype as the offspring and the offspring's offspring mate together. Or maybe even in the first generation if the genetic change is dominant.

OK so far? What would you correct?

So now we could have different genetic changes here and there in the population showing up in a few individuals here and there after a couple generations or so.

Different traits. A slightly different pattern of markings, of texture or color of fur, of length of tail, of shape of facial features, of ears, probably not anything really dramatic just differences here and there in the population.

Anything to object to so far?

If there is genetic drift that appreciably favors one or more of these new traits those will start appearing in the population in greater numbers. If the drift is very strong they night even come to characterize the population as a whole. I think the usual idea is that this should take a very long time. I tend to think in terms of a relatively small number of generations myself, fifty being a lot.

Any problem with that?

OR, if a part of the population gets lost and ends up in a new part of the forest and sets up housekeeping there, no longer with any reproductive contact with the old population, and continues on there breeding only among themselves, growing their population and so on, what I'm saying is that whatever genetic material they brought with them in greater frequency than that expressed in the old population will now come to characterize this new population. Say longer tails, a white diamond-shaped splotch over the nose, a lavender tinge to the coat, and shorter stature. All this built from the mutations that came with the individuals that formed the new population.

Now what I'm saying is that this is the basis for a new species or subspecies, this change in allele frequencies that comes about with the isolation of a small number of individuals from the greater population. As this new group inbreeds for many generations the new traits should begin to develop a characteristic look in the population at large, a new species.

Is there a problem with this scenario?

What I'm ALSO saying of course that in the development of this new species alleles for traits from the old species or any traits that are not those favored by greater frequency in the new population, will start to disappear from the population and if low frequency enough to begin with, may drop out altogether. At this point there is no new genetic input, there is only what was brought over from the old population, unfavored alleles are starting to disappear, which is the loss of genetic variability I'm talking about, and some of the high frequency alleles may soon be homozygous or fixed loci even through the entire population. (If enough of this happens for enough of the characteristic traits it seems to me that a genetic inability to breed with the former population could develop simply from this fact, but there can be many reasons for an inability to interbreed to develop between cousin populations of course).

If the original number of founders of the new population was quite small I would expect the change in allele frequencies to be dramatic enough to change the look of the new population rather rapidly, the unfavored alleles dropping out faster, and the inability to interbreed with the former population could develop very fast too, maybe even in a matter of a dozen generations or so, but give it fifty. It should show significantly decreased genetic variability from the former population by this point. The population should be sufficiently different from as well as unable to interbreed with the former population to earn it the label New Species.

Problems with this scenario?

Now at this point the idea here seems to be that mutations will just keep multiplying and prove me wrong about a genetic decrease that spells the end of evolution.

SO, what should happen at this point is what happened in the first part of this account: Mutations will be popping up in the new population just as they did in the original population. Over time some will be expressed in various individuals scattered throughout the population. If there is genetic drift some of the new traits could even come to change the overall look of the population. This is a form of evolution too as it involves a selection of sorts that changes allele frequencies, only within the population rather than by physical isolation. And then yes you will be getting even a population wide change. And again if a small number split off the other scenario will also develop that could ultimately lead to another New Species. If the mutations really do keep increasing the genetic diversity as you say. (ABE: Which again I'm allowing only for the sake of argument because I think sexual recombination of the existing genetic material explains it all quite well, mutations in fact add nothing but problems, and in any case it's clear any beneficial mutations that might arise and confer a valuable trait to the population are a very rare occurrence. /ABE)

AND there could be Natural Selection involved too, in the first phase or the second. But NS is simply a more drastic way of reducing genetic diversity by STRONGLY favoring a particular trait or set of traits so that the competing traits very rapidly die out. Any strong environmental pressure to adaptation to a particular kind of food or protection against a predator or anything along those lines would just exaggerate the tendencies I'm describing here. If hunters killed off as high a percentage of these creatures as they did the elephant seal, a really dramatic case of natural selection that the creature couldn't survive at all without intervention, then you'd see really dramatic decrease in genetic diversity even if the population was healthy enough to increase in numbers as the elephant seal did.

So back to the increase in diversity. Just go back to the original scenario. That increase has to be cut down IF the population is to evolve a new set of characteristics AS A POPULATION, and this is also what happens in genetic drift, it's simply another way this happens. Otherwise you'll have a nicely variegated population, perhaps millions of individuals with a very wide variety of traits among them.

Now you seem to want to call THAT situation "evolution" too which of course only muddies up the point I'm trying to make.

Are you REALLY saying MACROevolution doesn't depend on the formation of distinctively new populations, but that the normal variation from generation to generation without there being any sort of isolation or selection acting on it, would ultimately lead to MACROEVOLUTION just as well as the formation of distinctly different whole populations would?

Now I can't see how. I can see how you get new species but that requires the reduction in genetic diversity no matter how much you increase that diversity here and there. If it isn't reduced you aren't going to get a distinct new species. And if you don't get a distinct new species but only a very variegated large population I don't see how you are getting the kind of microevolution that Darwin identified in his finches and turtles and so on, and of course since to get this distinctive new population requires loss of genetic diversity end of evolution.

You've said I haven't sufficiently explained how the increases in genetic diversity don't answer my argument and I hope I've made it somewhat clearer.

I think YOU need to explain how you get new species without this reduction in genetic diversity. Of course you theoretically get new individual traits from the ongoing mutations, but unless they are selected or isolated so they can proliferate as a new population you aren't getting the kind of change that evolution is defined by.

Edited by Faith, : change wrong punctuation

Edited by Faith, : No reason given.

Edited by Faith, : add the ABE

Edited by Faith, : No reason given.


This message is a reply to:
 Message 90 by PaulK, posted 05-03-2014 5:20 AM PaulK has responded

Replies to this message:
 Message 95 by PaulK, posted 05-05-2014 4:59 AM Faith has not yet responded
 Message 101 by RAZD, posted 05-05-2014 8:18 AM Faith has responded

    
Faith
Member
Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 93 of 131 (725963)
05-05-2014 4:16 AM
Reply to: Message 89 by PaulK
05-03-2014 5:09 AM


Re: Beneficial mutations and other facts
The evolution of birds shows some problems with your argument, Faith.
Some traits aren't fixed. Size is the easy example. While a species has a relatively narrow range of size, the difference between a wren and an ostrich is huge. And there have been birds bigger, still.

But where have I said anything to imply it's fixed? AND remember I'm arguing from an assumption of separately created Kinds, so I don't necessarily assume a wren and an ostrich are genetically related. But if they happen to be, size is something I WOULD expect to vary dramatically in the original population from which they diverged.

Some traits open up a range of new possibilities. You can't have plumage patterns without plumage, there,s a huge range of shapes and colours and patterns. And the range of bill sizes and shapes is dependent on having a bill. Again, lots of new diversity.

Same answer as above. I'm assuming such a huge range of differences in plumage, bill size and shape and so on, it's the stuff from which microevolution is made, it's the stuff that makes the different birds in a ring species of birds. I don't believe that plumage or bills evolved from some other species of course, but even if they did it would be by the same methods I'm describing here.

And traits can be lost. A number of different lineages have lost the ability to fly. Penguins are adapted for swimming, ostriches and similar birds are too large for efficient muscle-powered flight.

And of course I've been talking about populations eliminating alleles haven't I? Alleles are the basis for traits, aren't they? So if the birds do happen all to be genetically related which may or may not be the case, this would be how all those differences came about. (ABE: if small wing size is favored in the daughter population -- simply by the luck of the draw in a population split --, the genetic material/alleles for wings large enough for flying would drop out. There's no reason why an ostrich couldn't fly but it would need enormous wings and those didn't make it into its gene pool /ABE).

There's no continuous narrowing down of traits, new variation is always coming in.

But focus on what happens when you have a new population based on a smallish number of founding individuals. Think about what the change in allele frequencies means. You are getting higher frequencies of some alleles for some versions of some traits than those in the original population, so you are getting new traits in the new population [[[ABE: I mean new traits in enough numbers to become CHARACTERISTIC of the new population /ABE] after some generations of inbreeding, and you are getting lower frequencies of the alleles for the different forms of those same traits in the old population and if low enough they drop out altogether. I wouldn't describe this as a "narrowing down of traits."

And I've tried to explain in that last post how you simply would never get anything you could call a New Species IF new variation did keep coming in and changing the whole population. Of course you will get new traits continuing to pop up in INDIVIDUALS within the population assuming there are still alleles for those traits in the mix [[ABE forgot here you are assuming mutations instead, but that works too/ABE]=, but unless they change the character of the whole population you are not getting a new species.

And at this point I've asked how you can have evolution if you are NOT getting new species. Which is something you are all claiming.

I know that you don't believe all this, but that isn't an argument. Nor is assuming that it couldn't happen. You need reasons why it can't. And we've been waiting for you to supply those for years.

I think I've done a lot more than assert my belief and assumption and hope that last post makes it even clearer. I've been giving reasons all along it seems to me.

Edited by Faith, : add comma

Edited by Faith, : add ABE about wing size for penguins and ostriches

Edited by Faith, : add phrase simply by the luck of the draw

Edited by Faith, : add ABEs: new traits enuf numbers to become characteristic...and "forgot you are assuming mutations...


This message is a reply to:
 Message 89 by PaulK, posted 05-03-2014 5:09 AM PaulK has responded

Replies to this message:
 Message 94 by Faith, posted 05-05-2014 4:44 AM Faith has not yet responded
 Message 96 by PaulK, posted 05-05-2014 5:27 AM Faith has not yet responded
 Message 102 by RAZD, posted 05-05-2014 8:27 AM Faith has not yet responded

    
Faith
Member
Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 94 of 131 (725964)
05-05-2014 4:44 AM
Reply to: Message 93 by Faith
05-05-2014 4:16 AM


" narrowing down of traits"
Need to say more about "narrowing down of traits" which I didn't grasp at first. You say this isn't happening. But it has to happen in Natural Selection, for instance, where only the adaptive traits are preserved. The ones that didn't work for the environmental situation drop out, are maybe even killed off by a predator. That's a narrowing down of traits isn't it?

But even the simple case of microevolution by migration of a small number of founders has to lead to the same situation, and a new species could develop from that new population, which really could happen in a short time if it has favorable conditions for long term inbreeding. It's going to develop its own traits that are different from those of the mother population. If the old traits are low frequency enough their alleles will disappear from the new population altogether. This is a "narrowing down of traits" isn't it?

Edited by Faith, : No reason given.


This message is a reply to:
 Message 93 by Faith, posted 05-05-2014 4:16 AM Faith has not yet responded

Replies to this message:
 Message 97 by PaulK, posted 05-05-2014 5:31 AM Faith has responded
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PaulK
Member
Posts: 12557
Joined: 01-10-2003
Member Rating: 2.4


(2)
Message 95 of 131 (725965)
05-05-2014 4:59 AM
Reply to: Message 92 by Faith
05-05-2014 3:46 AM


Re: I hope this is clarifying
quote:

I do think that anyone who thinks THROUGH what I'm saying should come to see it as I do.

So far, everybody who has thought through it has disagreed.

quote:

What happens to the genetic increases is hard to describe clearly. I might be able to illustrate it but I don't think that would be particularly clear either. But let me try to describe what I'm seeing.

I think that the real problem is that you have no clear idea yourself. Certainly making excuses for ignoring the increases in diversity suggests a lack of any real argument.

quote:

So what is happening in this population? Genetic changes are occurring from time to time. You attribute these to mutations, I attribute them to simple sexual recombination of existing alleles. Of course I'm sure you include this in your scenario too, we are merely disagreeing about the source of the genetic material.

Even if you're referring to phenotypic changes we know of examples due to mutations, so your insistence here is against the facts.

quote:

So these genetic changes are occurring. Say they ARE mutations in single individuals. How many of these occur in the germ cells? Anyway it's only those that will get passed on of course. And only the neutral and the "beneficial" ones if we assume the bad ones will be selected out. And as you've all pretty much agreed, this can take a very long time. If mutations could save the cheetah it will be a very long time if they can hold out that long. Anyway...

In all the discussions we've only been counting the mutations in the germ cells, so your first sentence suggests another failure to understand. Anyway, the cheetahs are such an extreme case that it's surprising that they're still around. But they are, despite human hunting inflicting another bottleneck on their population.

quote:

So after a generation or two the genetic changes start to show up in the phenotype as the offspring and the offspring's offspring mate together. Or maybe even in the first generation if the genetic change is dominant.

OK so far? What would you correct?


On top of the points that I've already made, selection is based on the trait, so that won't happen until the trait starts showing up in the populaton, so the ordering of your discussion is a bit odd.

quote:

If there is genetic drift that appreciably favors one or more of these new traits those will start appearing in the population in greater numbers. If the drift is very strong they night even come to characterize the population as a whole. I think the usual idea is that this should take a very long time. I tend to think in terms of a relatively small number of generations myself, fifty being a lot.

Any problem with that?


You seem to be confusing drift and selection. Selection works much faster than drift, because drift really is chance. And 50 generations is way too small. Even the rapid speciation proposed by Eldredge and Gould takes longer than that - and you should be thinking about the longer time between speciation events.

quote:

OR, if a part of the population gets lost and ends up in a new part of the forest and sets up housekeeping there, no longer with any reproductive contact with the old population, and continues on there breeding only among themselves, growing their population and so on, what I'm saying is that whatever genetic material they brought with them in greater frequency than that expressed in the old population will now come to characterize this new population. Say longer tails, a white diamond-shaped splotch over the nose, a lavender tinge to the coat, and general shorter stature. All this built from the mutations that came with the individuals that formed the new population.

There's likely to be a selective element, too, to fit local conditions.

quote:

What I'm ALSO saying of course that in the development of this new species alleles for traits from the old species or any traits that are not those favored by greater frequency in the new population, will start to disappear from the population and if low frequency enough to begin with, may drop out altogether. At this point there is no new genetic input, there is only what was brought over from the old population, unfavored alleles are starting to disappear, which is the loss of genetic variability I'm talking about, and some of the high frequency alleles may soon be homozygous or fixed loci even through the entire population. (If enough of this happens for enough of the characteristic traits it seems to me that a genetic inability to breed with the former population could develop simply from this fact, but there can be many reasons for an inability to interbreed to develop between cousin populations of course).

Of course this is largely repeating what you've already said. There isn't a lot of point in distinguishing between variations produced by mutations in the parent population and those that were inherited from earlier ancestors.

I CAN say that it has to be difficult to get an inability to interbreed in that way, for the simple reason that fertility barriers within a species are an obvious disadvantage.

quote:

If the original number of founders of the new population was quite small I would expect the change in allele frequencies to be dramatic enough to change the look of the new population rather rapidly, the unfavored alleles dropping out faster, and the inability to interbreed with the former population could develop very fast too, maybe even in a matter of a dozen generations or so, but give it fifty. It should show significantly decreased genetic variability from the former population by this point. The population should be sufficiently different from as well as unable to interbreed with the former population to earn it the label New Species.

If the number of founders is too small they'll need favourable conditions or a lot of luck to survive. And I think that complete loss of interfertility will take longer than you believe. How long have lions and tigers been separated ?

quote:

So back to the increase in diversity. Just go back to the original scenario. That increase has to be cut down IF the population is to evolve a new set of characteristics AS A POPULATION, and this is also what happens in genetic drift, it's simply another way this happens. Otherwise you'll have a nicely variegated population, perhaps millions of individuals with a very wide variety of traits among them.

Which is why speciation rarely, if ever, occurs in large populations (and is slow to occur if it does). This is the reasoning behind Mayr's proposal that speciation was the result of a small sub-population becoming isolated from the main population. You,ve referred to a small number of founders yourself. So let's agree that speciation is difficult, given a large population.

quote:

Now you seem to want to call THAT situation "evolution" too which of course only muddies up the point I'm trying to make.

More correctly I want to call the appearance of new variations in a large population, as well as the changes in allele frequency due to drift and selection in that population, evolution. Although there probably won't be much drift or selection going on, proportional to the population size.

quote:

Are you REALLY saying MACROevolution doesn't depend on the formation of distinctively new populations, but that the normal variation from generation to generation without there being any sort of isolation or selection acting on it, would ultimately lead to MACROEVOLUTION just as well as the formation of distinctly different whole populations would?

Of course not. And I've explained this before. In my view the usual process of macroevolution follows the original Punctuated Equilibrium model. A small population gets isolated and rapidly (say in about 1000 years) becomes distinctive enough to become a new population that does not interbreed with the parent population even if they should meet together. That population is successful (no need to consider those that are not), spreads and becomes much larger. For a much longer time it is stable. Variation increases mainly during the period of growth (where it is most rapid) and the period of stability. From this population, in time one or more smaller us populations will split off and themselves become new species.

That is not the only way it can happen, but I believe that it is the most common way.

quote:

Now I can't see how. I can see how you get new species but that requires the reduction in genetic diversity no matter how much you increase that diversity here and there. If it isn't reduced you aren't going to get a distinct new species. And if you don't get a distinct new species but only a very variegated large population I don't see how you are getting the kind of microevolution that Darwin identified in his finches and turtles and so on, and of course since to get this distinctive new population requires loss of genetic diversity end of evolution.

Of course, this is ignoring points I have already made in past discussion. The point is that the reduction is FOLLOWED by an increase, so we get a variegated large population that is still a distinct species.

quote:

You've said I haven't sufficiently explained how the increases in genetic diversity don't answer my argument and I hope I've made it somewhat clearer.

Since I can easily answer your argument by repeating points made in previous discussion it seems that you have not thought it through.

quote:

I think YOU need to explain how you get new species without this reduction in genetic diversity. Of course you theoretically get new individual traits from the ongoing mutations, but unless they are selected or isolated so they can proliferate as a new population you aren't getting the kind of change that evolution is defined by.

No, I don't. Because I am claiming that the vast majority of the new diversity is added after the speciation has occurred. And you haven't addressed that at all.


This message is a reply to:
 Message 92 by Faith, posted 05-05-2014 3:46 AM Faith has not yet responded

    
PaulK
Member
Posts: 12557
Joined: 01-10-2003
Member Rating: 2.4


(1)
Message 96 of 131 (725966)
05-05-2014 5:27 AM
Reply to: Message 93 by Faith
05-05-2014 4:16 AM


Re: Beneficial mutations and other facts
quote:

But where have I said anything to imply it's fixed

The point is that there are traits which are distinctive to a species, but not distinctive to all it's descendants. Thus, these traits never need "run out" of variation.

quote:

AND remember I'm arguing from an assumption of separately created Kinds, so I don't necessarily assume a wren and an ostrich are genetically related. But if they happen to be, size is something I WOULD expect to vary dramatically in the original population from which they diverged.

Your beliefs aren't really relevant, since they render the whole discussion moot. However, since even dogs vary less, at least proportionately, and that is the product of heavy selective breeding, it seems very doubtful that a single species could contain that degree if variation.

quote:

Same answer as above. I'm assuming such a huge range of differences in plumage, bill size and shape and so on, it's the stuff from which microevolution is made, it's the stuff that makes the different birds in a ring species of birds. I don't believe that plumage or bills evolved from some other species of course, but even if they did it would be by the same methods I'm describing here.

And that is an even worse failure. The point being made is that a new trait can open up a whole range of possible traits that couldn't,t be realised before. Nothing you say above answers that at all.

quote:

And of course I've been talking about populations eliminating alleles haven't I? Alleles are the basis for traits, aren't they?

And again, you miss the point. If a trait is lost the species need no longer maintain that trait, allowing diversity again.

quote:

But focus on what happens when you have a new population based on a smallish number of founding individuals. Think about what the change in allele frequencies means. You are getting higher frequencies of some alleles for some versions of some traits than those in the original population, so you are getting new traits in the new population [[[ABE: I mean new traits in enough numbers to become CHARACTERISTIC of the new population /ABE] after some generations of inbreeding, and you are getting lower frequencies of the alleles for the different forms of those same traits in the old population and if low enough they drop out altogether. I wouldn't describe this as a "narrowing down of traits."

If you are eliminating alleles for different traits, then of course you are narrowing down the traits present in the population. And, of course, as I,ve said before we need to consider the whole picture, not just a small part of it, even if that part is much more important than it's size suggests.

quote:

And I've tried to explain in that last post how you simply would never get anything you could call a New Species IF new variation did keep coming in and changing the whole population. Of course you will get new traits continuing to pop up in INDIVIDUALS within the population assuming there are still alleles for those traits in the mix [[ABE forgot here you are assuming mutations instead, but that works too/ABE]=, but unless they change the character of the whole population you are not getting a new species.

Yes, we know that adding variation to a species does not create a new species. But new traits appearing in individuals and NOT spreading to the entirity of the population IS exactly what an increase in variation IS. So really, you are objecting to increases in variation by saying that they are increases in variation.

quote:

And at this point I've asked how you can have evolution if you are NOT getting new species. Which is something you are all claiming.

Because new alleles in a population by definition change the allele frequency in that population. The frequency of that allele has increased from zero to one!

quote:

I think I've done a lot more than assert my belief and assumption and hope that last post makes it even clearer. I've been giving reasons all along it seems to me.

Since you seem to be repeating the same old errors over and over again and ignoring rebuttals I think it is quite clear that you don't have anything more than belief and assumption.


This message is a reply to:
 Message 93 by Faith, posted 05-05-2014 4:16 AM Faith has not yet responded

    
PaulK
Member
Posts: 12557
Joined: 01-10-2003
Member Rating: 2.4


Message 97 of 131 (725967)
05-05-2014 5:31 AM
Reply to: Message 94 by Faith
05-05-2014 4:44 AM


Re: " narrowing down of traits"
quote:

Need to say more about "narrowing down of traits" which I didn't grasp at first. You say this isn't happening. But it has to happen in Natural Selection, for instance, where only the adaptive traits are preserved. The ones that didn't work for the environmental situation drop out, are maybe even killed off by a predator. That's a narrowing down of traits isn't it?

The point is that the overall number of differing traits doesn't have to keep going down all the time. In fact we should expect it to hit a balance. Remember that I am not talking about the short term, like individual soeciation events, but the long term through a whole sequence of species.


This message is a reply to:
 Message 94 by Faith, posted 05-05-2014 4:44 AM Faith has responded

Replies to this message:
 Message 98 by Faith, posted 05-05-2014 7:55 AM PaulK has responded
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Faith
Member
Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 98 of 131 (725968)
05-05-2014 7:55 AM
Reply to: Message 97 by PaulK
05-05-2014 5:31 AM


Re: " narrowing down of traits"
All I can answer right now is this:

My first of the last three posts was to describe the accumulation of mutations in a basically static population, which makes for a variegated population that grows in numbers but doesn't evolve into a new species. You say I keep avoiding this, no I'm describing it and have been describing it all along. A static variegated populatuon is all you get with increases, you don't get new species. (Micro)evolving into a new (sub)species requires the selection and isolation processes which leads down the line to reduced genetic diversity.

If each new species then acquires mutations as did the first population you'll get the same variegated static population and the same scenario repeated ad infinitum over and over, you won't get evolution, just expanding populations with unique traits held by individuals but not dispersed in the whole group. They get dispersed only when there is some kind of selection mechanism or isolation, then you get a particular new trait or set of traits spreading throughout the whole population.

So you keep expanding and contracting down the line, you are not getting evolution. That's if mutations play any kind of significant role at all and even then that's just a generous concession to the best possible scenario in that case. Every time you have speciation you have something that interferes with it, and that presumably can keep on going indefinitely, there is no real speciation happening.

But if mutations don'


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Faith
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Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 99 of 131 (725969)
05-05-2014 7:55 AM
Reply to: Message 97 by PaulK
05-05-2014 5:31 AM


Re: " narrowing down of traits"
All I can answer right now is this:

My first of the last three posts was to describe the accumulation of mutations in a basically static population, which makes for a variegated population that grows in numbers but doesn't evolve into a new species. You say I keep avoiding this, no I'm describing it and have been describing it all along. A static variegated populatuon is all you get with increases, you don't get new species. (Micro)evolving into a new (sub)species requires the selection and isolation processes which leads down the line to reduced genetic diversity.

If each new species then acquires mutations as did the first population you'll get the same variegated static population and the same scenario repeated ad infinitum over and over, you won't get evolution, just expanding populations with unique traits held by individuals but not dispersed in the whole group. They get dispersed only when there is some kind of selection mechanism or isolation, then you get a particular new trait or set of traits spreading throughout the whole population.

So you keep expanding and contracting down the line, you are not getting evolution. That's if mutations play any kind of significant role at all and even then that's just a generous concession to the best possible scenario in that case. Every time you have speciation you have something that interferes with it, and that presumably can keep on going indefinitely, there is no real speciation happening.

But if mutations don't play any significant role, and it is all powered by sexual recombination then you WILL run out of genetic diversity down a line of evolving species.


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PaulK
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Posts: 12557
Joined: 01-10-2003
Member Rating: 2.4


(1)
Message 100 of 131 (725970)
05-05-2014 8:11 AM
Reply to: Message 98 by Faith
05-05-2014 7:55 AM


Re: " narrowing down of traits"
quote:

My first of the last three posts was to describe the accumulation of mutations in a basically static population, which makes for a variegated population that grows in numbers but doesn't evolve into a new species. You say I keep avoiding this, no I'm describing it and have been describing it all along. A static variegated populatuon is all you get with increases, you don't get new species. (Micro)evolving into a new (sub)species requires the selection and isolation processes which leads down the line to reduced genetic diversity.

You've been ignoring the consequence of this, which is that the new species is formed from whittling down the diversity of the variegated population, not the less varied original population. Thus diversity should follow a cycle of reduction and increase, not a monotonic decrease as your argument requires.

quote:

So you keep expanding and contracting down the line, you are not getting evolution

You say that, but it's obviously untrue. We're getting a whole sequence of distinct species - probably with multiple branchings - how is that NOT evolution?

quote:

Every time you have speciation you have something that interferes with it, and that presumably can keep on going indefinitely, there is no real speciation happening.

What is this something? You've said it before but never pointed to a single thing. So far as I can see you've just pulled that claim out of nothing.


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RAZD
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From: the other end of the sidewalk
Joined: 03-14-2004
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Message 101 of 131 (725971)
05-05-2014 8:18 AM
Reply to: Message 92 by Faith
05-05-2014 3:46 AM


what is macroevolution Faith?
So back to the increase in diversity. Just go back to the original scenario. That increase has to be cut down IF the population is to evolve a new set of characteristics AS A POPULATION, and this is also what happens in genetic drift, it's simply another way this happens. Otherwise you'll have a nicely variegated population, perhaps millions of individuals with a very wide variety of traits among them.

Not quite, Faith. Natural selection means those able to survive and breed pass on traits to the next generation, and this happens every generation. Those individuals that do not survive and breed do not pass on their specific mix of traits to the next generation. Thus the traits that are least beneficial to survival and reproduction tend to be removed from the population by this process

Genetic drift does not enhance fitness, as it is stochastic - chance, just like mutations. Genetic drift is neutral to fitness.

The number of trait varieties in the population will depend on the selection pressure, and when the pressure is low there will be more variation than when it is high.

Are you REALLY saying MACROevolution doesn't depend on the formation of distinctively new populations, but that the normal variation from generation to generation without there being any sort of isolation or selection acting on it, would ultimately lead to MACROEVOLUTION just as well as the formation of distinctly different whole populations would?

What is macroevolution Faith? Your definition please?

I think YOU need to explain how you get new species without this reduction in genetic diversity. Of course you theoretically get new individual traits from the ongoing mutations, but unless they are selected or isolated so they can proliferate as a new population you aren't getting the kind of change that evolution is defined by.

Take a deck of cards and shuffle them. Now cut the deck into two piles. If you had 52 cards in the original deck, how many cards do you have in the two piles?

Is there more or less diversity in the two piles taken as a whole than in the original deck?

So the diversity is still there, what you don't have is gene flow from one pile to the other, but diversity looks at the whole ecosystem not just a single population. The individuals in the two populations will continue to behave and interact within the ecosystem just as they would as a combined population. Each daughter population will also acquire different new mutations, mutations not shared with the other daughter population and thus the differences that existed between the original daughter populations will grow as different diversity is added to each population by mutations.

Look at this image at two different levels, one at the "1000" elevation in the "Lysite" area and the other a the "1500" elevation mark in the "Lower Cabin" area.

The widths of each band represents the diversity of the population with regards to size. The population at the 1000 elevation is very spread out, and the two populations at the 1500 elevation are more clumped up (thicker bars means more individuals of that size): Notharctus nunienus on the left and Notharctus venticolus on the right.

Does the total width from smallest Notharctus nunienus to largest Notharctus venticolus exceed the total width of the population at the 1000 elevation?

quote:
... The two species later became even more distinct, and the descendants of nunienus are now labeled as genus Smilodectes instead of genus Notharctus.

As you look from bottom to top, you will see that each group has some overlap with what came before. There are no major breaks or sudden jumps. And the form of the creatures was changing steadily.


This same process occurs in each of the two branching populations and total diversity has increased.

Enjoy


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This message is a reply to:
 Message 92 by Faith, posted 05-05-2014 3:46 AM Faith has responded

Replies to this message:
 Message 103 by Faith, posted 05-05-2014 8:28 AM RAZD has responded

  
RAZD
Member
Posts: 18250
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


Message 102 of 131 (725972)
05-05-2014 8:27 AM
Reply to: Message 93 by Faith
05-05-2014 4:16 AM


Re: Beneficial mutations and other facts
And I've tried to explain in that last post how you simply would never get anything you could call a New Species IF new variation did keep coming in and changing the whole population. Of course you will get new traits continuing to pop up in INDIVIDUALS within the population assuming there are still alleles for those traits in the mix [[ABE forgot here you are assuming mutations instead, but that works too/ABE]=, but unless they change the character of the whole population you are not getting a new species.

And at this point I've asked how you can have evolution if you are NOT getting new species. Which is something you are all claiming.

What is a species?

What makes a "new species" different from a previous one?

Enjoy


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This message is a reply to:
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Faith
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Posts: 24384
Joined: 10-06-2001
Member Rating: 1.0


Message 103 of 131 (725973)
05-05-2014 8:28 AM
Reply to: Message 101 by RAZD
05-05-2014 8:18 AM


Re: what is macroevolution Faith?
Fitness as an adaptive mechanism is just an article of faith, in reality there is hardly any struggle in the Darwinian sense to adapt. Just another tenet of the theory assumed as fact without evidence. There are certainly some striking adaptations but they can just as easily be the right beak finding the right food as the available food determining the right beak.

ABE: That is, microevolution is a natural process that happens with sexual recombination and will produce new subspecies simply from reproductive isolation of a limited number of individuals, without any struggle at all. Microevolution I mean sexual recombination will evolve various beak types as a matter of course. If there is food in the vicinity that a particular beak handles particularly well it will gravitate to that food even if food for all the other kinds of beaks is present too. Then the offspring that inherit the same beak, also choosing that kind of food, will develop more distinctive versions of that beak type. It doesn't have to be this scenario where the food determines how the beak evolves. /ABE

As for what is macroevolution: I define it functionally as the point at which microevolution so decreases genetic diversity that no further evolution is possible.

However, here's another attempt: It's whatever CAN vary in the given genome of the species, its peculiar traits and the genes for those traits with their various alleles. No variation is possible outside those built-in design limits.

ABE: Sorry, I'm tired. I mean microevolution is whatever can vary and anything beyond that would be macroevolution but it can'

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 101 by RAZD, posted 05-05-2014 8:18 AM RAZD has responded

Replies to this message:
 Message 104 by PaulK, posted 05-05-2014 8:54 AM Faith has not yet responded
 Message 105 by RAZD, posted 05-05-2014 9:12 AM Faith has not yet responded

    
PaulK
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Posts: 12557
Joined: 01-10-2003
Member Rating: 2.4


(1)
Message 104 of 131 (725975)
05-05-2014 8:54 AM
Reply to: Message 103 by Faith
05-05-2014 8:28 AM


Re: what is macroevolution Faith?
quote:

Fitness as an adaptive mechanism is just an article of faith, in reality there is hardly any struggle in the Darwinian sense to adapt. Just another tenet of the theory assumed as fact without evidence. There are certainly some striking adaptations but they can just as easily be the right beak finding the right food as the available food determining the right beak.

That's a very silly thing thing to say in this thread, of all threads. Unless you are accusing the Grants of fraud? If so we'll want rather more than your jaundiced opinion to back it up.

quote:

As for what is macroevolution: I define it functionally as the point at which microevolution so decreases genetic diversity that no further evolution is possible.

That would be extinction. Which is pretty useless as a definition of macroevolution.

quote:

However, here's another attempt: It's whatever CAN vary in the given genome of the species, its peculiar traits and the genes for those traits with their various alleles. No variation is possible outside those built-in design limits.

That doesn't even make sense as a definition of macroevolution.


This message is a reply to:
 Message 103 by Faith, posted 05-05-2014 8:28 AM Faith has not yet responded

    
RAZD
Member
Posts: 18250
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.2


(2)
Message 105 of 131 (725977)
05-05-2014 9:12 AM
Reply to: Message 103 by Faith
05-05-2014 8:28 AM


Re: what is macroevolution Faith?
Fitness as an adaptive mechanism is just an article of faith, in reality there is hardly any struggle in the Darwinian sense to adapt. ...

How then do you explain the same level of populations from generation to generation even though more offspring are produced than are needed to fill the vacancies made by the dying? Take spawning salmon as an example -- how many eggs are produced and how many salmon return the following year?

How do you explain the peppered moth population swing from light to dark and from dark to light? If fitness was not involved would not there be the same number of light and dark moths each year?

... There are certainly some striking adaptations but they can just as easily be the right beak finding the right food as the available food determining the right beak.

And if the small beak cannot find seeds it can open does it just hang in stasis until the right food appears?

As for what is macroevolution: I define it functionally as the point at which microevolution so decreases genetic diversity that no further evolution is possible.

Which of course is a "Faith fantasy" definition not incorporated into biology or evolution science.

However, here's another attempt: It's whatever CAN vary in the given genome of the species, its peculiar traits and the genes for those traits with their various alleles. No variation is possible outside those built-in design limits.

Also a "Faith fantasy" definition not incorporated into biology or evolution science.

Do you understand that when you use words that you define one way and science defines another way that you are NOT talking about the same thing?

Faith: macroevolution is "x" and it never occurs
Science: macroevolution is "y" and it has been observed, so we know it occurs.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

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