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Author Topic:   MACROevolution vs MICROevolution - what is it?
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 256 of 712 (816882)
08-12-2017 6:48 PM
Reply to: Message 255 by PaulK
08-12-2017 11:47 AM


Re: the usual silly wrong linear analogy
I didn't assume a purpose. But there must be some causal reason why those individuals were selected relating to the features in question. And there is not.

No there doesn't have to be any causal reason, it was purely random, they simply happened to have genes for big heads and jaws that didn't get phenotypically expressed until there were enough of them in few enough individuals to bring it about over some number of generations. They didn't have to have them, there is no reason to think they couldn't have survived well enough without them, but their genes brought out that trait and it caused them to change their diet.

it is certainly random selection when a particular small number of individuals is reproductively isolated,

That is drift, not selection.

Drift is a form of random selection that occurs within a population. There are other forms such as the random selection of some number of individuals that migrate away from the parent population. It's selection in the sense I described and it's random.


This message is a reply to:
 Message 255 by PaulK, posted 08-12-2017 11:47 AM PaulK has responded

Replies to this message:
 Message 257 by PaulK, posted 08-13-2017 1:42 AM Faith has responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 257 of 712 (816887)
08-13-2017 1:42 AM
Reply to: Message 256 by Faith
08-12-2017 6:48 PM


Re: the usual silly wrong linear analogy
quote:

No there doesn't have to be any causal reason, it was purely random

If it is purely random it is drift, not selection - at least by the way everyone else uses the terms. For reasons that should be obvious - it is not a difficult concept. And the founder effect is obviously inadequate when none of the founders have the traits in question.

And you need selection to explain why the lizards changed in such a short time.

So let me repeat. I was not using your private definition of selection and drift is inadequate - especially the founder effect. If you actually tried thinking about it you would realise this.


This message is a reply to:
 Message 256 by Faith, posted 08-12-2017 6:48 PM Faith has responded

Replies to this message:
 Message 258 by Faith, posted 08-13-2017 3:52 AM PaulK has responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 258 of 712 (816893)
08-13-2017 3:52 AM
Reply to: Message 257 by PaulK
08-13-2017 1:42 AM


Re: the usual silly wrong linear analogy
Drift occurs within a population as I understand it, and I've never seen the random formation of a separated daughter population called drift.

The selection needed to explain the rapid change is in the original small number of founders, that original random selection. Such a small number is all that is needed for very rapid change. And thirty years is far more than would be needed; the change should come about within a few generations, give it ten years.

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 257 by PaulK, posted 08-13-2017 1:42 AM PaulK has responded

Replies to this message:
 Message 259 by PaulK, posted 08-13-2017 3:59 AM Faith has responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 259 of 712 (816894)
08-13-2017 3:59 AM
Reply to: Message 258 by Faith
08-13-2017 3:52 AM


Re: the usual silly wrong linear analogy
quote:

Drift occurs within a population as I understand it, and I've never seen the formation of a daughter population called drift.

I have certainly seen the relevant aspect - the Founder effect - called drift. And since it is random, why should it be called selection rather than drift ?

quote:

The selection needed to explain the rapid change is in the original small number of founders.

Try thinking about it. Explain how it could be that none of the founders could have the traits while all of the current population do, without a change in allele frequencies.
It just isn't possible (unless it is an environmental response after all)


This message is a reply to:
 Message 258 by Faith, posted 08-13-2017 3:52 AM Faith has responded

Replies to this message:
 Message 260 by Faith, posted 08-13-2017 4:06 AM PaulK has responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 260 of 712 (816895)
08-13-2017 4:06 AM
Reply to: Message 259 by PaulK
08-13-2017 3:59 AM


Re: the usual silly wrong linear analogy
The same way Darwin's pigeons did not have the traits they came to have after his assiduous selection program.

"Without a change in allele frequencies?" You are really not getting this. The founding population has the different allele frequencies from their parent population. It is those new allele frequencies that bring out the larger head and jaws over a number of generations of sexual recombination among those new allele frequencies. It is you who aren't thinking.


This message is a reply to:
 Message 259 by PaulK, posted 08-13-2017 3:59 AM PaulK has responded

Replies to this message:
 Message 261 by PaulK, posted 08-13-2017 4:22 AM Faith has responded
 Message 275 by Taq, posted 08-14-2017 10:51 AM Faith has responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 261 of 712 (816896)
08-13-2017 4:22 AM
Reply to: Message 260 by Faith
08-13-2017 4:06 AM


Re: the usual silly wrong linear analogy
quote:

The same way Darwin's pigeons did not have the traits they came to have after his assiduous selection program.

If you think that selectively breeding from birds with the traits is the same as randomly breeding from a small starting population you have a problem.

quote:

"Without a change in allele frequencies?" You are really not getting this

On the contrary. You see, I have actually thought about it.

quote:

The founding population has the different allele frequencies from their parent population.

And none of them have the traits in question. Whether you forget that or fail to see the significance is unimportant. But it is very important.

quote:

It is those new allele frequencies that bring out the larger head and jaws over a number of generations of sexual recombination among those new allele frequencies. It is you who aren't thinking.

Assuming that things must be the way you want them to be isn't real thinking.

Are we really to believe that the vast majority of gene combinations taken from the original founders have the new traits ? That it was just by chance that none of the founders had those traits ? It's absurd. And it is the only way you could be right.

Consider the example of a recessive allele. Even if you picked a founder population who all had one copy of that allele you would still only have a frequency of 50%. For the trait associated with that allele to take over the population that allele would have to increase in frequency to 100%.

If you want to say that things can work out the way you want you are going to have to explain how it can be possible. No vague statements about "recombination" somehow doing it (especially as it obviously isn't enough). An actual explanation.


This message is a reply to:
 Message 260 by Faith, posted 08-13-2017 4:06 AM Faith has responded

Replies to this message:
 Message 262 by Faith, posted 08-13-2017 6:04 AM PaulK has responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 262 of 712 (816897)
08-13-2017 6:04 AM
Reply to: Message 261 by PaulK
08-13-2017 4:22 AM


Re: the usual silly wrong linear analogy
Yes I do think the same kind of result can come about through either Darwin's selection or the random combination of genetic material in a randomly assembled founding population, though it would no doubt take longer in the random scenario to get all the relevant genetic material into the mix. It all depends on what genes were present in that founding population and nobody knows but it can be inferred from the results that whatever increases head and jaw size was present and dominant and would be increased over generations of recombination. While there may have been additional factors involved, I don't see any need for them.

If you don't see that the small founding number is already a new set of gene frequencies that will determine the development of the lizard population, you really have NOT thought about it enough despite your declarations.

Are we really to believe that the vast majority of gene combinations taken from the original founders have the new traits ?

I would expect it to emerge over a number of generations, not be a matter of "vast majority" but something that gets increased over time. That's how I think of Darwin's pigeons. He'd pick a pigeon with a very slightly larger breast perhaps and breed for that characteristic, finding that all it takes to increase it is repeating matings of the birds that have that characteristic. I don't see why this couldn't happen randomly. We're not talking about "new traits," all it takes is ordinary sexual recombination of a new set of gene frequencies to bring out hitherto unexpressed traits over a number of generations.

That it was just by chance that none of the founders had those traits ? It's absurd. And it is the only way you could be right.

There's a lot of stuff potential in the genome of any animal that doesn't get expressed except under special circumstances, including random selection of a small founding population, especially effects that increase over generations like the exaggerated pigeon breasts or the exaggerated lizard heads. You get quite noticeable differences from population to population in a ring species and there's no reason to assume anything other than inbreeding of changed gene frequencies to explain it.

However, it is possible that the founding population did contain a lizard or two or three that had a slightly larger head than the others, but not enough to be noticed. Surely Darwin's original slightly larger pigeon breast was hardly noticeable. If the trait in question is governed by more than one gene, which is the case with most traits after all, then increasing it over generations isn't a big mystery.

Consider the example of a recessive allele. Even if you picked a founder population who all had one copy of that allele you would still only have a frequency of 50%. For the trait associated with that allele to take over the population that allele would have to increase in frequency to 100%.

Well, in my scenario all genes originally had only two alleles, and that's my default assumption, so each individual of the founder population should have had at least one copy of the recessive allele. Following normal Mendelian genetics that allele should frequently be homozygous in subsequent generations. But there are probably many genes that affect head and jaw size so with such small founding numbers we should be getting homozygosity at many of those loci in a few generations, increasing the effect. We could suppose something like sexual selection at this point to speed up the processes involved.

Believe it or not I'm just pursuing what looks to me like the evidence, none of this has anything to do with "what I want" so you can stop with the incessant insults. Darwin's pigeons came to mind at one point, I wasn't looking for that angle on things. It's interesting because it suggests the possibility of increasing size over generations just from ordinary sexual recombination. However, I don't need it to argue for ordinary sexual recombination of new gene frequencies since that's my standard argument for even the most dramatic changes over short periods of time.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 261 by PaulK, posted 08-13-2017 4:22 AM PaulK has responded

Replies to this message:
 Message 263 by PaulK, posted 08-13-2017 6:40 AM Faith has responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 263 of 712 (816898)
08-13-2017 6:40 AM
Reply to: Message 262 by Faith
08-13-2017 6:04 AM


Re: the usual silly wrong linear analogy
quote:

Yes I do think the same kind of result can come about through either Darwin's selection or the random combination of genetic material in a randomly assembled founding population, though it would no doubt take longer in the random scenario to get all the relevant genetic material into the mix

In reality it is very unlikely. You would need drift or selection to get even one really distinctive variety.

quote:

It all depends on what genes were present in that founding population and nobody knows but it can be inferred from the results that whatever increases head and jaw size was present and dominant and would be increased over generations of recombination.

The fact that it was not seen in any of the founding population shows that it was certainly not dominant - and any significant increase would require significant increases in the relevant alleles.

quote:

If you don't see that the small founding number is already a new set of gene frequencies that will determine the development of the lizard population, you really have NOT thought about it enough despite your declarations.

A new set of frequencies, yes. But sufficient to produce what is seen without it being obvious in the founding population, certainly not.

quote:

I would expect it to emerge over a number of generations, not be a matter of "vast majority" but something that gets increased over timE

You misunderstand. The number of possible combinations - which is what I am speaking of - cannot increase unless new alleles are introduced.

quote:

That's how I think of Darwin's pigeons. He'd pick a pigeon with a very slightly larger breast perhaps and breed for that characteristic, finding that all it takes to increase it is repeating matings of the birds that have that characteristic. I don't see why this couldn't happen randomly.

That is selection or drift changing the frequency of alleles. You claim that it can happen without either.

quote:

We're not talking about "new traits," all it takes is ordinary sexual recombination of a new set of gene frequencies to bring out hitherto unexpressed traits over a number of generations.

Please can you not waste time with pointless semantic arguments which change nothing. Whether we call the traits new or not I am not considering mutations at all at this point.

quote:

There's a lot of stuff potential in the genome of any animal that doesn't get expressed except under special circumstances, including random selection of a small founding population, especially effects that increase over generations like the exaggerated pigeon breasts or the exaggerated lizard heads. You get quite noticeable differences from population to population in a ring species and there's no reason to assume anything other than inbreeding of changed gene frequencies to explain it.

All of which IS due to changing allele frequencies. Which you claim is not required.

quote:

However, it is possible that the founding population did contain a lizard or two or three that had a slightly larger head than the others, but not enough to be noticed. Surely Darwin's original pigeon breast was hardly noticeable. If the trait in question is governed by more than one gene, which is the case with most traits after all, then increasing it over generations isn't a big mystery

You fail to understand the issue. The question is not how a bigger head appeared in one or two lizards, the question is how did it come to be that all of the present population have bigger heads - and the other features that distinguish them from the parent population. I say that - unless it is an environmental response - to do it in the time available requires rapid selection. You insist that somehow it can occur without any change in allele frequencies from the founder population. And accuse me of "not thinking" about it when I disagree.

quote:

Well, in my scenario all genes originally had only two alleles, and that's my default assumption, so each individual of the founder population should have had at least one copy of the recessive allele

I hope that you can see that that is unlikely.

quote:

Following normal Mendelian genetics that allele should frequently be homozygous in subsequent generations.

Where "frequently" is only about one quarter of the population, even with the very favourable assumption that all the adults had a copy of the allele. A quarter is rather less than all.

And if we have any more than one gene to think about the proportion with the full set of new traits will be much smaller than a quarter.

quote:

But there are probably many genes that affect head and jaw size so with such small founding numbers we should be getting homozygosity at many of those loci in a few generations, increasing the effect.

With many genes the situation is hopeless. If we assume that it is all due to recessive genes the proportion of the population with the full set of traits goes down to one sixteenth with two genes, one in 64 with three, one in 256 with four. Unless you have major changes in allele frequencies - which you claim are not necessary - it is obviously hopeless.

quote:

Believe it or not I'm just pursuing what looks to me like the evidence, none of this has anything to do with "what I want" so you can stop with the incessant insults.

What evidence lead you to believe that no changes in allele frequency - relative to the founding population - were required to explain the changes in the lizards ? What evidence lead you to claim that I hadn't thought about the matter ? If you had anything to support your claim why haven't you produced it ?

And calling criticisms insults is just a lie. Especially when the evidence clearly supports those criticisms.


This message is a reply to:
 Message 262 by Faith, posted 08-13-2017 6:04 AM Faith has responded

Replies to this message:
 Message 264 by Faith, posted 08-13-2017 7:32 AM PaulK has responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 264 of 712 (816899)
08-13-2017 7:32 AM
Reply to: Message 263 by PaulK
08-13-2017 6:40 AM


Re: the usual silly wrong linear analogy
You don't need additional selection if the original founding gene frequencies have clear highs and lows, which is likely to be the case among such a small number of individuals. Extreme lows will become lower and drop out over time, while the highs come to dominate.

I don't need your abusive attitude.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 263 by PaulK, posted 08-13-2017 6:40 AM PaulK has responded

Replies to this message:
 Message 265 by PaulK, posted 08-13-2017 8:08 AM Faith has responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 265 of 712 (816901)
08-13-2017 8:08 AM
Reply to: Message 264 by Faith
08-13-2017 7:32 AM


Re: the usual silly wrong linear analogy
quote:

You don't need additional selection if the original founding gene frequencies have clear highs and lows, which is likely to be the case among such a small number of individuals. Extreme lows will become lower and drop out over time, while the highs come to dominate.

Which would still be a change of allele frequencies through drift. And too slow for this case. And come to that we still have the problem that the traits in question are not seen in the founders, and don't seem to be known in the population at large.

quote:

I don't need your abusive attitude.

All you are getting is push-back against your arrogance - criticism you invite with your attitude. If you bothered to think things through - if you bothered to actually get things right instead of proclaiming that you are right without understanding and blaming those who disagree with you, you might get a response more to your liking,

Justified criticism is neither insult nor abuse. If you are insulted by what you really are, and what you are really doing the answer is to do better.


This message is a reply to:
 Message 264 by Faith, posted 08-13-2017 7:32 AM Faith has responded

Replies to this message:
 Message 266 by Faith, posted 08-13-2017 1:01 PM PaulK has responded
 Message 267 by Faith, posted 08-13-2017 1:04 PM PaulK has responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 266 of 712 (816913)
08-13-2017 1:01 PM
Reply to: Message 265 by PaulK
08-13-2017 8:08 AM


Re: the usual silly wrong linear analogy
Your attitude is abusive and all I've been doing is pursuing my thoughts about these things so you have no excuse.
This message is a reply to:
 Message 265 by PaulK, posted 08-13-2017 8:08 AM PaulK has responded

Replies to this message:
 Message 269 by PaulK, posted 08-13-2017 1:37 PM Faith has not yet responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 267 of 712 (816914)
08-13-2017 1:04 PM
Reply to: Message 265 by PaulK
08-13-2017 8:08 AM


Re: the usual silly wrong linear analogy
I'll say it again. If Darwin could get traits from a founding pair of pigeons that didn't exist in either one of them, the lizards could also produce such a new trait just from previously unexpressed combinations of existing genes.

Fine, add drift, but drift is a form of selection and it can happen just as rapidly as what I'm talking about from one generation to the next.


This message is a reply to:
 Message 265 by PaulK, posted 08-13-2017 8:08 AM PaulK has responded

Replies to this message:
 Message 268 by PaulK, posted 08-13-2017 1:23 PM Faith has not yet responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


Message 268 of 712 (816916)
08-13-2017 1:23 PM
Reply to: Message 267 by Faith
08-13-2017 1:04 PM


Re: the usual silly wrong linear analogy
quote:

I'll say it again. If Darwin could get traits from a founding pair of pigeons that didn't exist in either one of them, the lizards could also produce such a new trait just from previously unexpressed combinations of existing genes.

Then I'll just point out again that selection was needed, and it is certainly needed to have a rare trait take over the population in a few decades. And we aren't talking about just one trait

quote:

Fine, add drift, but drift is a form of selection and it can happen just as rapidly as what I'm talking about from one generation to the next.

Drift is not a form of selection and it is slow because it is not selection.


This message is a reply to:
 Message 267 by Faith, posted 08-13-2017 1:04 PM Faith has not yet responded

    
PaulK
Member
Posts: 12988
Joined: 01-10-2003
Member Rating: 3.0


(1)
Message 269 of 712 (816917)
08-13-2017 1:37 PM
Reply to: Message 266 by Faith
08-13-2017 1:01 PM


Re: the usual silly wrong linear analogy
quote:

Your attitude is abusive

And that's a lie.

quote:

and all I've been doing is pursuing my thoughts about these things so you have no excuse.

And that's not true. After all it is quite clear now that i was correct to point out that further changes in allele frequency would be needed and your assertion that I hadn't thought about the matter was false and baseless. You are only thinking about the matter now - to the extent you are - because I pointed out the obvious problems that you hadn't considered.

If you don't like being criticised then you could at least try not to deserve it.


This message is a reply to:
 Message 266 by Faith, posted 08-13-2017 1:01 PM Faith has not yet responded

    
Faith
Member
Posts: 25897
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 270 of 712 (816956)
08-14-2017 10:24 AM


Evolution has a built-in stopping point
Before it gets completely lost, I would just like to restate my original position, which is sometimes affirmed by PaulK and others, but nevertheless gets easily lost in side issues:

Evolution is not a straight linear one-foot-after-the-other process because in order to get new varieties or races or breeds or species the genetic material for other varieties must be reduced, and completely lost in some cases.

I think a daughter population can show dramatic changes from the parent population in a relatively short period of time simply from the random selection of a small founding population. I gave the example of the release of five pairs of lizards onto the Pod Mrcaru island, which developed big heads and jaws over thirty-plus years. I don't think more than the random selection of a small number of individuals is needed to explain this, as there would most likely be dramatic new gene frequencies in the founding number which would bring out the changes simply through a few generations of sexual recombination.

I brought this up because the necessary genetic loss is never acknowledged in discussions of evolution, and the computer simulation models perpetuate the same wrong idea of an unimpeded series of changes from microevolution to macroevolution. Apparently even when they take "selection" into account they fail to represent this fact.

Edited by Faith, : No reason given.


Replies to this message:
 Message 282 by PaulK, posted 08-14-2017 11:52 AM Faith has responded
 Message 284 by dwise1, posted 08-14-2017 9:00 PM Faith has responded
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