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Author Topic:   Evolution Requires Reduction in Genetic Diversity
RAZD
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Message 991 of 1034 (769846)
09-25-2015 2:03 PM
Reply to: Message 986 by Faith
06-25-2015 7:42 AM


From "We have the fossils" thread
From Evolution. We Have The Fossils. We Win. Message 230 Faith says:

The dog breeds change AS A WHOLE, all parts at once, all the bones changing to conform to the overall design of the breed while still articulating according to the Basic Dog Template as it were.

Dead wrong. Every mutt mixture of breeds and half breeds and feral wild dog proves you are wrong. That would be creationist fantasy transformation, certainly not evolution. Every breeder will tell you that you are wrong.

I suspect that you think I'm wrong about something I didn't say, but let me expand a bit. When a breed is being developed, a particular trait or set of traits may be selected but what you get is the overall change I'm talking about: you don't get a bulldog head and legs with a greyhound torso, or a Chihuahua head on a Great Dane body, even if none of those body parts are selected. What you get is an overall proportional structure that goes with the selected traits. It appears that DNA does its thing within the general template or design of the species and not just by piecemeal changes of particular traits. This is perhaps more mysterious and even divine than anything else about how DNA operates.

But you are clearly not in a mood to pursue this topic and there's way too much discord between our views to spend more time on it right now. I don't want to say I'm leaving the thread because as usual I don't know if I will, but I think I should because everything I need to say I've said and I'll just get worn out trying to answer a million objections. We'll see how it goes.

Again you have made a trivially true but irrelevant comment: all organisms are "complete" formed from their particular mix of DNA. Not one organism isn't "complete" ...

... but you also do not get a "complete" change of the whole offspring from the parent, you don't get a bulldog born "complete" from a wolf, which is what it looks like you said (" all parts at once, all the bones changing ... ").

... you don't get a bulldog head and legs with a greyhound torso, or a Chihuahua head on a Great Dane body, even if none of those body parts are selected. ...

Correct, you do not get a chimera, what you get is a mixture of traits from the parents and from mutations. If those parents are different breeds you get a mosaic of traits. But you do not as a rule get a completely new breed in one generation -- it is a mutt at this point. You get part of the new breed, and build on that for the next generation until you reach the desired goal.

... What you get is an overall proportional structure that goes with the selected traits. ...

Again a mundanely true but pointless comment: the offspring will be a complete organism with a "proportional structure" that goes with that particular organism.

What it won't have necessarily is the same proportions as the parent or the end result. There will be intermediate stages with intermediate distributions of structural proportions until the final result is achieved.

... It appears that DNA does its thing within the general template or design of the species and not just by piecemeal changes of particular traits. ...

And again it seems you have it precisely backwards. Evolution works by piecemeal changes that are selected and built on to make the next round of changes in the next generation, that there is no template or design for any new species that is being formed.

... This is perhaps more mysterious and even divine than anything else about how DNA operates.

Or you just don't understand genetics.

But you are clearly not in a mood to pursue this topic and there's way too much discord between our views to spend more time on it right now. I don't want to say I'm leaving the thread because as usual I don't know if I will, but I think I should because everything I need to say I've said and I'll just get worn out trying to answer a million objections. We'll see how it goes.

THIS is YOUR thread to burble on as much as you want to.

Enjoy

Edited by RAZD, : .


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This message is a reply to:
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RAZD
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(1)
Message 992 of 1034 (769890)
09-26-2015 11:16 AM
Reply to: Message 986 by Faith
06-25-2015 7:42 AM


Also from "We have the Fossils" thread
Reply to Faith on Evolution. We Have The Fossils. We Win., Message 233

Not only does genetics not work incrementally, ...

Except we know this is false.

... nor make such just-so changes as those needed to get from the reptilian to the mammalian ear bones ...

As evidenced by the many intermediate fossils that are in the spatial/temporal matrix at the right time and in the right place ...

... there is no need to change the reptilian ear, it works just fine. Nature has no reason to make a mammalian ear out of it -- that is, there is no selection pressure involved. No need to make a mammal out of a reptile at all. So why would there be any changes in that direction?

Evolution does not work on "need" and you know this (or should by now). It works in incremental steps of improvement built on improvement -- better hearing improves the likelihood of survival, so an ear that hears better is selected over one that doesn't.

Just as occurred for eyes and other senses.

ABE: Oh and another thing I meant to include: the basic body structure of an animal is apparently hard-wired into the genome, and so are necessary features like ear design for pete's sake. ...

And this is you making stuff up that has nothing to do with real genetics.

Stuff that we know is wrong.

... The ear structure is just not going to change and neither is the basic reptile body structure. ...

And we know that that is wrong too.

... Genetics varies things like size and shape, whilekeeping the basic body design, fur, or scales in the case of reptiles? color etc. You always get a reptile. You always get a bear, though a small black one or a huge brown one. You always get a dog or a cat. The basic template is in the genome. Huge variations yes but it's always a dog a cat a reptile a bear or whatnot. ...

Standard creationist PRATTle. You've been told how cladistics shows descent from a parent population will always be a member of that parent clade. The formation of nested hierarchies is what shows that evolution explains the diversity of life.

All mammals have the "basic body design" of the common mammalian clade ancestor population, Huge variations yes but it's always a mammal ...

... which has the "basic body design" of the common tetrapod clade ancestor population. Huge variations yes but it's always a tetrapod ...

Random variation is what genetics actually does when there is no selection pressure. It's the most common way varieties and races form in nature. ...

Genetic drift also occurs when there is selection pressure, on traits that are not being selected, but may be taken along for the ride with the gene under selection.

... It's the most common way varieties and races form in nature. ...

It is one of the common ways varieties form. Another is via selection.

... New finch beaks. No reason for it, no selection pressure, it's just a variation possible in the genome and when that genetic option becomes more frequent in a population that is reproductively isolated, the finch gets a new beak. Then it chooses a different food that the new beak can handle.

Which we know is precisely backwards of how it actually happens.

But then you've got those millions of years in there to make this reptile mammal thing happen. You'd only need those millions of years ...

And we know this is false, both in the fact that the evidence shows that the earth IS very very very old, and in the fact that it isn't a matter of "needing" it to be old. That is more creationist PRATTLe.

... You'd only need those millions of years if you kept getting mistakes, unfunctioning ears. Lotta deaf reptile babies then. I guess they just died out or why didn't they adapt to their deafness? ...

Except that the intermediate fossils show there was a fully functional ear through the whole passage of transition. So again you are wrong about what the fossils show and about how evolution actually works ...

... It would of course take time to come up with variations that maintain the necessary relation between the bones for a functioning ear. ...

And we know that each generation would have functioning ears because evolution works by small incremental changes that alter elements but maintain function. Just as the jaw continued to function as it transitioned from the non-mammalian amniote jaw through a phase that had two jaw joints and then to the mammalian jaw.

... But there's no reason for that to happen even in a billion years. This isn't anything like how breeds form, ...

It is precisely how breeds form, because it is how evolution works, gradual modifications from generation to generation within the breeding population:

(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats.

Notice how this applies to dog breeds, finch beaks and yes, even therapsid jaws and ears.

... this IS macroevolution and it's impossible.

Except that is impossible because it ISN'T macroevolution, just more creationist PRATTle.

In the biological fields in general and in the field of evolution in particular, macroevolution is defined as process of forming a nested hierarchy by descent of new species from common ancestor populations, via the combination of anagenesis and cladogenesis, and resulting in an increase in the diversity of life. This is often confusing, especially to creationists, because there is no additional mechanism of evolution involved, rather this is just the result of looking at evolution over many generations and within different ecologies.

The process of anagenesis, with the accumulation of changes over many generations, is an observed, known objective fact, and not an untested hypothesis.

The process of cladogenesis, with the subsequent formation of a branching nested genealogy of descent from common ancestor populations is an observed, known objective fact, and not an untested hypothesis.

This means that the basic processes of "macroevolution" are observed, known objective facts, and not untested hypothesies, even if major groups of species are not observed forming (which would take many many generations), the processes are known, and thus they are by definition possible.

The problem I'm trying to highlight here is that discussions of fossil evolution completely ignore what genetics actually does. Evo theory just goes on and on about how such and such changes occurred over those millions of years without knowing if it is even possible, and in reality it's just not.

And curiously, the problem you are actually highlighting is that ignorance of evolution leads to false conclusions not based on facts or evidence, but pure imagination, with all the assurance of Dunning-Kruger effect ignorance.

When every premise you use is wrong, the conclusions are invariably invalid.

Garbage in garbage out.

Enjoy


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This message is a reply to:
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PaulK
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(3)
Message 993 of 1034 (769909)
09-26-2015 1:45 PM


Population Genetics - Faith's errors
Faith:
quote:

So as I was pondering (and praying about) that example I realized that for such an event to have occurred would require many stages of population genetics, and that led me to recognize that population genetics doesn't work that way: first it doesn't make incremental changes from generation to generation: in a condition of reproductive isolation it makes clear DIFFERENT phenotypic variations in many individuals that over many further recombinations can become part of a new look for the entire new population.

The first error is that population genetics does not describe phenotypic changes. It describes how alleles change in frequency.

The second error is that population genetics DOES work incrementally over generations. (Indeed, a generation would be a 'round of population genetics')

The third error is - as usual - to exclude the role of mutation

Apparently prayer is no substitute for making the effort to understand what you are talking about.


Replies to this message:
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jar
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Message 994 of 1034 (769921)
09-26-2015 4:22 PM
Reply to: Message 993 by PaulK
09-26-2015 1:45 PM


Re: Population Genetics - Faith's errors
PaulK writes:

Apparently prayer is no substitute for making the effort to understand what you are talking about.

Yup; Pray in one hand and spit in the other. See which one gets filled first.

Pray never trumps reality I fear.

But yet again, Faith has NEVER provided the evidence to support "genetic depletion" (whatever that actually means) or explain why genetics shows that folk living at the same time as Adam and even thousands of years before Adam show pretty much the same genetic signature as folk living today or why there is no evidence of the genetic depletion that had to have occurred if either of the Biblical Floods had actually happened and not been just fantasy.


Anyone so limited that they can only spell a word one way is severely handicapped!

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Faith
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Message 995 of 1034 (770032)
09-28-2015 12:54 PM
Reply to: Message 993 by PaulK
09-26-2015 1:45 PM


Re: Population Genetics - Faith's errors
So as I was pondering (and praying about) that example I realized that for such an event to have occurred would require many stages of population genetics, and that led me to recognize that population genetics doesn't work that way: first it doesn't make incremental changes from generation to generation: in a condition of reproductive isolation it makes clear DIFFERENT phenotypic variations in many individuals that over many further recombinations can become part of a new look for the entire new population.

The first error is that population genetics does not describe phenotypic changes. It describes how alleles change in frequency.

Yes, and the phenotypes that emerge come from the greater frequencies.

The second error is that population genetics DOS work incrementally over generations. (Indeed, a generation would be a 'round of population genetics')

Sticking with the one and only example I focus on, that of a reproductively isolated daughter population formed from a relatively small number of individuals, what happens in the first few generations is the emergence of a number of different phenotypes in different individuals due to the new gene frequencies, and after whatever number of generations of inbreeding it takes to mix all the genetic types, the population as a whole acquires a new phenotypic look. Where's the incremental development?

The third error is - as usual - to exclude the role of mutation

That's because, as I've explained so many times, the source of alleles has nothing to do with the processes that reduce genetic diversity.

I found this interesting discussion from a dog-breeding site / They discuss many problems connected with breeding programs, and refer to natural populations for comparison from time to time. The only mention of mutations is in the paragraph about Hardy-Weinberg stability of large populations in which mutations are specifically excluded from the discussion. They discuss all sorts of genetic processes without mutation entering in at all.

...in limited, genetically isolated populations such as CKC breeds a certain amount of genetic diversity is lost with each reproductive event, through the action of genetic drift, inbreeding and artificial selection,

The article is concerned with the problems of breeders and the only real description of natural populations is that very large stable sort of population. They don't discuss the examples I keep focusing on, where active evolution is going on and genetic diversity is consequently being lost from subspecies to subspecies or race to race. But what they say about breeding makes it clear that what they are battling is the same tendency: the reduction in genetic diversity due to the development of a particular phenotypic expression.

That really ought to be pretty good support for what I've been arguing.

Might as well answer JAR here too:

But yet again, Faith has NEVER provided the evidence to support "genetic depletion" (whatever that actually means) or explain why genetics shows that folk living at the same time as Adam and even thousands of years before Adam show pretty much the same genetic signature as folk living today or why there is no evidence of the genetic depletion that had to have occurred if either of the Biblical Floods had actually happened and not been just fantasy.

I've many times given the evidence of the effect of the One Flood bottleneck which is the 7% homozygosity in the human genome. It's a reduction in genetic diversity from what had to have been the former more heterozygous condition, though not yet genetic depletion, which comes with extreme homozygosity.

The dog breeding article mentions the problems connected with homozygosity.


This message is a reply to:
 Message 993 by PaulK, posted 09-26-2015 1:45 PM PaulK has responded

Replies to this message:
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 Message 997 by PaulK, posted 09-28-2015 2:25 PM Faith has not yet responded
 Message 1001 by RAZD, posted 09-28-2015 3:27 PM Faith has responded

    
Dr Adequate
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Message 996 of 1034 (770034)
09-28-2015 1:23 PM
Reply to: Message 995 by Faith
09-28-2015 12:54 PM


Re: Population Genetics - Faith's errors
That's because, as I've explained so many times, the source of alleles has nothing to do with the processes that reduce genetic diversity.

Oh Faith, not again, not again.


This message is a reply to:
 Message 995 by Faith, posted 09-28-2015 12:54 PM Faith has not yet responded

Replies to this message:
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PaulK
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Member Rating: 3.0


(1)
Message 997 of 1034 (770037)
09-28-2015 2:25 PM
Reply to: Message 995 by Faith
09-28-2015 12:54 PM


Re: Population Genetics - Faith's errors
quote:

Yes, and the phenotypes that emerge come from the greater frequencies

I'm glad that you accept that you misunderstood what population genetics is actually about.

quote:

Sticking with the one and only example I focus on, that of a reproductively isolated daughter population formed from a relatively small number of individuals, what happens in the first few generations is the emergence of a number of different phenotypes in different individuals due to the new gene frequencies, and after whatever number of generations of inbreeding it takes to mix all the genetic types, the population as a whole acquires a new phenotypic look. Where's the incremental development

Unfortunately you've gone right back to repeating your first error immediately after accepting that it was an error. Population genetics does not describe the phenotypic changes. It describes changes in allele frequency and those changes DO take place incrementally over the generations.

Although to be quite honest I would not be surprised to find some examples of incremental change in dogs if we had a decent record. Declaring that it didn't happen without the records that would let you know if it had is just an unsupported opinion.

quote:

That's because, as I've explained so many times, the source of alleles has nothing to do with the processes that reduce genetic diversity.

That's a typical Faith excuse. You can't make a relevant factor irrelevant just by refusing to talk about it.

quote:

The article is concerned with the problems of breeders and the only real description of natural populations is that very large stable sort of population.

Or to put it another way they are really only interested in pure-bred dogs, the problems faced by breeders of those dogs and what to do about them. It's all short-term stuff, related to small, isolated and heavily inbred populations which are rarely found in nature. With artificial selection tending to make the problems worse.

quote:

That really ought to be pretty good support for what I've been arguing.

It isn't. It's almost completely irrelevant. You'd have to be nuts to think that a heavily artificial, short-term situation (which would be expected to lead to extinction) has much to do with long term evolutionary change in nature.

Edited by PaulK, : Minor clarification


This message is a reply to:
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Admin
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Message 998 of 1034 (770039)
09-28-2015 2:51 PM
Reply to: Message 996 by Dr Adequate
09-28-2015 1:23 PM


Re: Population Genetics - Faith's errors
Dr Adequate writes:

Oh Faith, not again, not again.

Please be more specific.


--Percy
EvC Forum Director

This message is a reply to:
 Message 996 by Dr Adequate, posted 09-28-2015 1:23 PM Dr Adequate has not yet responded

    
Admin
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From: EvC Forum
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Member Rating: 3.2


(1)
Message 999 of 1034 (770041)
09-28-2015 3:00 PM
Reply to: Message 997 by PaulK
09-28-2015 2:25 PM


Re: Population Genetics - Faith's errors
PaulK writes:

Although to be quite honest I would not be surprised to find some examples of incremental change in dogs if we had a decent record.

Not sure what you mean here. Are you referring to incremental changes in what we today consider stable dog breeds? It makes sense in that context, but your comments might be misinterpreted as being aimed at the development of a new breed of dog, where incremental changes are of course apparent, otherwise breeders wouldn't be able to select mates for the next generation. Or maybe you mean some possibility I missed?


--Percy
EvC Forum Director

This message is a reply to:
 Message 997 by PaulK, posted 09-28-2015 2:25 PM PaulK has responded

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PaulK
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Posts: 12760
Joined: 01-10-2003
Member Rating: 3.0


(1)
Message 1000 of 1034 (770044)
09-28-2015 3:18 PM
Reply to: Message 999 by Admin
09-28-2015 3:00 PM


Re: Population Genetics - Faith's errors
I'm referring to cases where a sequence of phenotypic changes build on top of each other. It wouldn't be that surprising to find a few short sequences. It doesn't even require mutations. If multiple genes affect a feature select for one until an allele is fixed in the breed. Sometime later select on another and so on.

Maybe comparing a breed derived from another with the "parent" breed might show something of the sort, although obviously it couldn't demonstrate a sequence of more than two steps without getting into the genetics. But I would be very, very surprised if Faith has even made a decent attempt at making comparisons of that sort.


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 Message 999 by Admin, posted 09-28-2015 3:00 PM Admin has acknowledged this reply

    
RAZD
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From: the other end of the sidewalk
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(1)
Message 1001 of 1034 (770045)
09-28-2015 3:27 PM
Reply to: Message 995 by Faith
09-28-2015 12:54 PM


Re: Population Genetics - Faith's errors continue
The first error is that population genetics does not describe phenotypic changes. It describes how alleles change in frequency.

Yes, and the phenotypes that emerge come from the greater frequencies.

No, the change in allele frequency is due to the different phenotypes having different levels of success in surviving and breeding. Those phenotypes are already in the population.

The second error is that population genetics DOS work incrementally over generations. (Indeed, a generation would be a 'round of population genetics')

Sticking with the one and only example I focus on, ...

Arbitrarily chosen because it is the only one that fits your concept?

... that of a reproductively isolated daughter population formed from a relatively small number of individuals, ...

Or what is known as the Founder Effect

quote:
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942,[1] using existing theoretical work by those such as Sewall Wright.[2] As a result of the loss of genetic variation, the new population may be distinctively different, both genotypically and phenotypically, from the parent population from which it is derived. In extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species.

And if it is successful, this would lead to new traits being selected from available mutations that occur in that population, which would separate it further from the parent population as it becomes a new species. And

quote:
The founder effect is a special case of genetic drift, occurring when a small group in a population splinters off from the original population and forms a new one. The new colony may have less genetic variation than the original population, and through the random sampling of alleles during reproduction of subsequent generations, continue rapidly towards fixation. This consequence of inbreeding makes the colony more vulnerable to extinction.

So this leads to fixation of some existing alleles in the population, and this becomes a base for further evolution. And

quote:
The variation in gene frequency between the original population and colony may also trigger the two groups to diverge significantly over the course of many generations. As the variance, or genetic distance, increases, the two separated populations may become distinctively different, both genetically and phenotypically, although not only genetic drift but also natural selection, gene flow and mutation will all contribute to this divergence. ...

MAY ... over the course of many generations ... become distinctively different ... but also natural selection, gene flow and mutation will all contribute to this divergence. ... so it isn't guaranteed to happen, and when it does it will be through many standard evolutionary processes.

The founding event is not the end of the story, but rather a new beginning.

... what happens in the first few generations is the emergence of a number of different phenotypes in different individuals due to the new gene frequencies, and after whatever number of generations of inbreeding it takes to mix all the genetic types, the population as a whole acquires a new phenotypic look. ...

It's not quite correct to say the "population ... acquires a new phenotypic look" because that is a misuse of the word phenotype. The proper word is Phenome:

quote:
Although a phenotype is the ensemble of observable characteristics displayed by an organism, the word phenome is sometimes used to refer to a collection of traits, while the simultaneous study of such a collection is referred to as phenomics.

Similar to "genome" for a population. The population acquires a new mix of different phenotypes compared to the parent population, and this mix constitutes the phonome of that population.

... Where's the incremental development?

In those intermediate generations. As different alleles sort out and get fixed in the population from generation to generation.

Of course not just the original founding traits will be mixed but any new traits that arise by mutation during this period, and the new traits will have less survival pressure in a small population as the population tries to expand into their ecology.

The rate of fixed new traits/mutations in a population after an extinction event has been shown to increase rapidly after the event and then slow down as the ecological niches become filled. See forams:

quote:
As revealed by the ancient record left by the foram family, the story of recovery after extinction is every bit as busy and colorful as some scientists have long suspected.

"What we've found suggests that the rate of speciation increases dramatically in a biological vacuum," Parker said. " ...


So the rate of increasing diversity is quicker in a vacuum than in a filled ecosystem.

The third error is - as usual - to exclude the role of mutation

That's because, as I've explained so many times, the source of alleles has nothing to do with the processes that reduce genetic diversity.

Indeed, it negates it.

I found this interesting discussion from a dog-breeding site / They discuss many problems connected with breeding programs, and refer to natural populations for comparison from time to time. The only mention of mutations is in the paragraph about Hardy-Weinberg stability of large populations in which mutations are specifically excluded from the discussion. They discuss all sorts of genetic processes without mutation entering in at all.

...in limited, genetically isolated populations such as CKC breeds a certain amount of genetic diversity is lost with each reproductive event, through the action of genetic drift, inbreeding and artificial selection,

The article is concerned with the problems of breeders and the only real description of natural populations is that very large stable sort of population. They don't discuss the examples I keep focusing on, where active evolution is going on and genetic diversity is consequently being lost from subspecies to subspecies or race to race. But what they say about breeding makes it clear that what they are battling is the same tendency: the reduction in genetic diversity due to the development of a particular phenotypic expression.

That really ought to be pretty good support for what I've been arguing.

Or not, because their interest is in the populations not changing ... perhaps because their interest is in imposing artificial stasis on the breeds once they have been developed ... new pups are inspected and ones that don't meet spec are discarded, which would artificially remove all new traits\mutations from the breeding population, a totally artificial circumstance with no relation to founder populations or any other natural situation.

Might as well answer JAR here too:
But yet again, Faith has NEVER provided the evidence to support "genetic depletion" (whatever that actually means) or explain why genetics shows that folk living at the same time as Adam and even thousands of years before Adam show pretty much the same genetic signature as folk living today or why there is no evidence of the genetic depletion that had to have occurred if either of the Biblical Floods had actually happened and not been just fantasy.

I've many times given the evidence of the effect of the One Flood bottleneck which is the 7% homozygosity in the human genome. It's a reduction in genetic diversity from what had to have been the former more heterozygous condition, though not yet genetic depletion, which comes with extreme homozygosity.

So it was 7% before and 7% after this purported flood event, except that this should also show up in ALL animal populations, to an even higher degree in those "kinds" that only had two on the ark. There is no such genetic signature of a universal bottleneck event.

So no, you have not answered Jars question. You have not presented any evidence of a sudden decrease in the genetic diversity of humans or a single animal, and curiously science moves on evidence not hyperbolic imagination.

He has a thread on this problem for YECs ... perhaps you should take this argument to that thread ... No genetic bottleneck proves no global flood ...

The dog breeding article mentions the problems connected with homozygosity.

Again, dog breeds are artificial bottlenecked populations that are continually trimmed of new traits and mutations.

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)

This message is a reply to:
 Message 995 by Faith, posted 09-28-2015 12:54 PM Faith has responded

Replies to this message:
 Message 1002 by Faith, posted 09-28-2015 6:44 PM RAZD has responded

  
Faith
Member
Posts: 25282
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 1002 of 1034 (770051)
09-28-2015 6:44 PM
Reply to: Message 1001 by RAZD
09-28-2015 3:27 PM


Re: Population Genetics - Faith's errors continue
No, the change in allele frequency is due to the different phenotypes having different levels of success in surviving and breeding. Those phenotypes are already in the population.

Change in allele frequency most obviously occurs with the formation of a new isolated population by a relatively small number of individuals. This is the classic view. I don't know where you are getting yours. Other things may contribute to the same effect of course, but population splits are THE known cause of changes in gene/allele frequencies. It is that change that gives rise to new phenotypes in the new population that didn't exist in the parent population, that eventually over generations of inbreeding create a new phenotypic appearance in the new population that differentiates it from the parent population. Evolution, in a word. Of the micro sort of course.

Sticking with the one and only example I focus on, ...

Arbitrarily chosen because it is the only one that fits your concept?

It's the example that demonstrates evolution in action. A large stable population that isn't evolving (see breeder article if you doubt there is such a thing) doesn't demonstrate what happens during active evolution. Active evolution that produces new phenotypes doesn't happen without reduced genetic diversity. Reduced genetic diversity is the inevitable TREND of evolution. At the extremes it becomes genetic depletion. The extremes define the boundary of a species beyond which evolution is impossible for lack of genetic fuel. The extremes can be avoided in breeding by careful attention to maintaining heterozygosity, as the dog breeding article points out. The same article says that nature seems to work to maintain heterozygosity as well, it being the most healthy state of a population. But when new populations arise from splits you start to see the effect I'm talking about: active evolution, the production of new varieties, is always accompanied by reduced genetic diversity.

Mutation merely supplies alleles (according to current ToE anyway), but alleles are what get reduced by the evolutionary processes. Mutation therefore does nothing to prevent reduced genetic diversity.

Cheers.


This message is a reply to:
 Message 1001 by RAZD, posted 09-28-2015 3:27 PM RAZD has responded

Replies to this message:
 Message 1003 by RAZD, posted 09-28-2015 9:27 PM Faith has responded
 Message 1005 by PaulK, posted 09-29-2015 1:08 AM Faith has responded

    
RAZD
Member
Posts: 18656
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 1003 of 1034 (770055)
09-28-2015 9:27 PM
Reply to: Message 1002 by Faith
09-28-2015 6:44 PM


Re: Population Genetics - Faith's errors continue
No, the change in allele frequency is due to the different phenotypes having different levels of success in surviving and breeding. Those phenotypes are already in the population.

Change in allele frequency most obviously occurs with the formation of a new isolated population by a relatively small number of individuals. This is the classic view. ...

Curiously, I was pointing out that what you said in Message 995 ("Yes, and the phenotypes that emerge come from the greater frequencies.") was somewhat backwards. The founding phenotypes were those already in the founding population at the time of the founding event, and it is the phenome formed by all those founding individual phenotypes that formed the pool of alleles\genes\traits for that founding populations next generation, the founding phenotypes did not emerge from those alleles.

Perhaps you weren't being clear: following generations certainly would mix those alleles around, but whether that would necessarily create new phenotypes compared to the parent population is not clear. They were all available in both populations.

You DO however get new alleles from mutations, and new mutations can have a higher success rate in small populations, particularly if it is a new open ecology with lots of opportunities, and THAT can certainly (virtually guaranteed to) lead to new phenotypes.

Additionally, a small (developing) population in a new ecology will have different selection pressures than the (mature) parent population had, and this will result in different phenotype selection, which could also cause further drift.

... population splits are THE known cause of changes in gene/allele frequencies. ...

They are A known cause and it is ALSO known that population splits may NOT necessarily result in changes in gene/allele frequencies. You are once again cherry-picking bits and parts that fit your fantasy and ignore the rest.

Mutations and selection are another means of altering the frequencies. Drift does not cause the other processes to suddenly cease. Each generation has new mutations (genome change), each generation undergoes selection for survival and reproductive success (phenome change).

... It is that change that gives rise to new phenotypes in the new population that didn't exist in the parent population, ...

Do you have evidence of such new phenotype where you can guarantee that it is not due to mutation and selection?

Each new generation has new mutations, and when a small population exhibits population growth, that is evidence that selection pressure would be low, meaning more new mutations survive than in a mature population. Again, as pointed out in Message 1001, this has actually been observed to occur.

... Evolution, in a word. Of the micro sort of course.

Indeed:

(1) The process of evolution involves changes in the composition of hereditary traits, and changes to the frequency of their distributions within breeding populations from generation to generation, in response to ecological challenges and opportunities for growth, development, survival and reproductive success in changing or different habitats.

Mutations and selection and drift all cause evolution.

... It is that change that gives rise to new phenotypes in the new population that didn't exist in the parent population, that eventually over generations of inbreeding create a new phenotypic appearance in the new population that differentiates it from the parent population. ...

Let me fix that for you:

... It is the change in allele frequencies due to the founder effect plus new mutations not in the parent population and different selection pressures that gives rise to new phenotypes in the new population that didn't exist in the parent population, that eventually over generations of breeding creates a new phenome for the new population that differentiates it from the parent population phenome.

There is no reason that a mixture of alleles that are identical to alleles existing in the parent population will magically create a suddenly new phenotype that never existed in the parent population. With the shift in alleles available in a population due to a founding event being different also means that the phenotypes in that population will have different frequencies. It is with the addition of mutations that you get new traits and it is with the change in selection pressures that you get new phenotypes.

It's the example that demonstrates evolution in action. ...

It's is one of many examples that demonstrate evolution in action.

... A large stable population that isn't evolving (see breeder article if you doubt there is such a thing) doesn't demonstrate what happens during active evolution. ...

Large stable populations exist in stable ecologies, where selection is relatively constant, towards the population average, ie - for stassis.

Breeder selection to remove any change from the breed population is intentional to guarantee the desired goal of population stassis.

This doesn't mean evolution is not active, it is very active, with high pressure to maintain successful phenotypes rather than to create new ones.

... Active evolution that produces new phenotypes doesn't happen without reduced genetic diversity. ...

Wrong. Evolution that produces new phenotypes doesn't happen without low selection pressure. High selection pressure reduces genetic diversity (which is what maintains stable populations in stable ecologies).

... Reduced genetic diversity is the inevitable TREND of evolution. ...

Still wrong, and repeating doesn't change that. Again, you ignore mutations, because it is your fantasy, not for any reason based on actual evidence.

What's amusing is that you focus on a situation which can result in high selection of new mutations compared to a large stable population as your theater stage to claim genetic diversity is reduced.

... At the extremes it becomes genetic depletion. The extremes define the boundary of a species beyond which evolution is impossible for lack of genetic fuel. ...

Which is caused by high selection pressure, such as habitat destruction, overhunting, disease, etc etc etc. and which is why there are more extinct species than living species.

You would think that this steady reduction in genetic diversity that you claim would result in more later species being challenged and robust ancestral populations that did not go extinct. Could you have it backwards again?

... extremes can be avoided in breeding by careful attention to maintaining heterozygosity, as the dog breeding article points out. The same article says that nature seems to work to maintain heterozygosity as well, it being the most healthy state of a population. ...

In large stable populations living in stable ecologies. However this magical aspect of nature did not prevent all those extinct species from surviving, so I kind of get a feeling that it is not really representative of how biology actually works in wild systems.

... But when new populations arise from splits you start to see the effect I'm talking about: active evolution, the production of new varieties, is always accompanied by reduced genetic diversity.

Let me fix that for you:

But when new populations arise from splits you start to see the effect I'm talking about: active evolution, the production of new varieties, is always accompanied by low selection pressure, with population growth allowing more new mutations to spread through the population.

Mutation merely supplies alleles (according to current ToE anyway), but alleles are what get reduced by the evolutionary processes. Mutation therefore does nothing to prevent reduced genetic diversity.

Take an empty plastic jug and put a small hole in the bottom. Now place it in the sink and run water into it. At low levels of flow from the tap the level in the jug will stabilize at a low level. With higher rates of flow the level will stabilize at a higher level. Is it possible for the rate of flow to be so high that it overflows the jug? Is it possible for the rate to be so low that no water remains in the jug? The water from the tap represents new mutations, the hole represents selection (the size of the hole represents the amount of selection pressure), and the amount of water in the jug represents the genetic diversity.

Whether or not more alleles are removed by selection than are provided by mutation depends on selection pressure.

Again you assume something to be universally true that isn't, instead you are talking about a special case of a special case, and one that is not that common.

Why are there so many extinct species if the ancient species had better genetic diversity?

Enjoy


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This message is a reply to:
 Message 1002 by Faith, posted 09-28-2015 6:44 PM Faith has responded

Replies to this message:
 Message 1004 by Faith, posted 09-29-2015 1:07 AM RAZD has responded

  
Faith
Member
Posts: 25282
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.1


Message 1004 of 1034 (770061)
09-29-2015 1:07 AM
Reply to: Message 1003 by RAZD
09-28-2015 9:27 PM


Re: Population Genetics - Faith's errors continue
Curiously, I was pointing out that what you said in Message 995 ("Yes, and the phenotypes that emerge come from the greater frequencies.") was somewhat backwards. The founding phenotypes were those already in the founding population at the time of the founding event, and it is the phenome formed by all those founding individual phenotypes that formed the pool of alleles\genes\traits for that founding populations next generation, the founding phenotypes did not emerge from those alleles.

The founding phenotypes soon disappear as the new population reproduces because they were founded on the allele frequencies of the original population. Those individuals of course do collectively contain the new gene frequencies, but the new gene frequencies bring out new phenotypes that eventually eclipse the originals. The originals don't contribute anything to the ultimate phenome (if that is really the word) that will ultimately characterize the new population. Their alleles will but in entirely new combinations. It's meaningless to talk about the original phenome; what emerges eventually from the new allele frequencies is the entirely new phenome of the new population over generations of reproductive mixing.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 1003 by RAZD, posted 09-28-2015 9:27 PM RAZD has responded

Replies to this message:
 Message 1008 by RAZD, posted 09-29-2015 7:52 AM Faith has not yet responded
 Message 1010 by RAZD, posted 09-29-2015 8:45 AM Faith has not yet responded

    
PaulK
Member
Posts: 12760
Joined: 01-10-2003
Member Rating: 3.0


Message 1005 of 1034 (770062)
09-29-2015 1:08 AM
Reply to: Message 1002 by Faith
09-28-2015 6:44 PM


Faith's new math
quote:

Change in allele frequency most obviously occurs with the formation of a new isolated population by a relatively small number of individuals.

Change in allele frequency goes on all the time. It's just faster in small populations.

quote:

This is the classic view. I don't know where you are getting yours. Other things may contribute to the same effect of course, but population splits are THE known cause of changes in gene/allele frequencie

NO. This is another of your misunderstandings. Selection and drift cause changes in allele frequencies (although selection can also maintain them). Population splits can increase the rate of drift (because the sub-populations are smaller than the whole). But the real reason they are important is that they eliminate gene flow between the sub-populations allowing them to change relative to each other.

quote:

Mutation merely supplies alleles (according to current ToE anyway), but alleles are what get reduced by the evolutionary processes. Mutation therefore does nothing to prevent reduced genetic diversity.

Only if you believe that 2 - 1 + 1 = 1. Faith's new math.


This message is a reply to:
 Message 1002 by Faith, posted 09-28-2015 6:44 PM Faith has responded

Replies to this message:
 Message 1006 by Faith, posted 09-29-2015 1:21 AM PaulK has responded

    
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