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Author Topic:   WTF is wrong with people
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 357 of 457 (708577)
10-11-2013 8:31 AM
Reply to: Message 344 by Faith
10-10-2013 6:43 PM


Re: Environment-driven evolution
Faith writes:
It's just that many other concepts have entered into the theory since Darwin, and a big one is the population genetics understanding of evolution coming about through change in gene/allele frequencies.
Your lack of understanding is causing you to become very confused. When someone defines evolution as changing allele frequencies over time and doesn't mention selection, as they might do when discussing population genetics, it doesn't mean they have a different definition of evolution that downplays selection's role. They're merely assuming the audience already knows the definition of evolution. Population genetics understands that by far the biggest player in changing allele frequencies over time is selection.
Faith, you can't let every occurrence of an incomplete or contextual definition (or even a very poor definition as in the case of the Berkeley site, which you would have recognized had the come to that site with a decent understanding of evolution) lead you astray. First and foremost evolution is descent with modification and natural selection. That will never change.
So don't get so uppity about what I know and don't know.
You're asking people not to become upset and frustrated when your frequent misunderstandings and misinterpretations become a big waste of time. I don't think that's going to happen. I can't believe that after your decade here we still have to explain the key role selection plays in evolution.
Evolution by descent with modification is STILL the basic plank and that plank is assumed in my argument.
You're forgetting selection. Again.
Natural Selection is one way allele frequencies change because it's one way a new subpopulation is created.
And again, selection does not create subpopulations. Since all individuals of a population are subjected to the same selection pressures, just how do you imagine a subpopulation being created by selection?
So once again you have things completely backwards. The way it actually works is that first a subpopulation is formed, then if it is subjected to different selection pressures it will begin to differ from the main population.
Subpopulations are often smaller than the original population and when they are then we have the trend to decreased genetic diversity that shows that evolution has a stopping point. Even if you add in mutations this trend is not affected.
The creation of a subpopulation is an event that reduces genetic diversity, but it only occurs once while the process of mutation occurs over and over and over again with each and every act of reproduction.
Let's say a river changes course, splitting a subpopulation of a 1000 individuals off from a larger population of 1,000,000. That's one single event causing reduced genetic diversity. But every new offspring in the subpopulation will contain a number of mutations, probably somewhere between 10 and 100. Since the subpopulation is not dividing into sub-subpopulations and sub-sub-subpopulations, in other words, since the process that reduces genetic diversity is no longer occurring, just how do you imagine genetic diversity continuing to decline as mutations pour in?
--Percy
Edited by Percy, : Improved clarity.

This message is a reply to:
 Message 344 by Faith, posted 10-10-2013 6:43 PM Faith has not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 358 of 457 (708579)
10-11-2013 8:40 AM
Reply to: Message 347 by Faith
10-10-2013 7:28 PM


Re: Environment-driven evolution
Faith writes:
For cryin out loud I've been saying all this all along!!!!! And I JUST GOT THROUGH SAYING IT AGAIN ABOUT NATURAL SELECTION!!! What I'm adding, or emphasizing, is just that ALL these things bring about POPULATION SPLITS, which is THE FUNDAMENTAL DEFINITIVE way allele frequencies get changed. YES, THROUGH ALL THOSE DIFFERENT MECHANISMS.
Sheesh.
Sheesh, yourself.
The gorilla of evolutionary change is natural selection. Nothing else comes close. If you think otherwise than just imagine a simple bacterial experiment. In one set of petri dishes you provide a variety of different nutrient mixes, in the other set you provide the standard nutrient mix the bacteria are used to. I guarantee you that every single time you run this experiment that the vast majority of change will be in the bacteria with the modified nutrient sources.
I can't believe you can be so wrong about something as obvious as selection. Breeders long ago discovered that the fastest and most effective way to achieve desired change is selection. They use no other approach because no other approach works. It's simple rational thinking and logic, Faith. Use some.
--Percy

This message is a reply to:
 Message 347 by Faith, posted 10-10-2013 7:28 PM Faith has not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 359 of 457 (708582)
10-11-2013 8:55 AM
Reply to: Message 356 by Tangle
10-11-2013 8:15 AM


Re: Environment-driven evolution
Tangle writes:
Oh, absolutely. I was just trying to separate the agents than cause change from the agent that directs change once caused because Faith thinks that merely separating a population both causes and directs change.
Oh, okay. And going back and looking at the message chain again I can see this now, but I'm confident that Faith will interpret your lack of mention of selection in that particular message as an indication that you don't believe selection is important. Incredible, I know, but there it is.
--Percy

This message is a reply to:
 Message 356 by Tangle, posted 10-11-2013 8:15 AM Tangle has replied

Replies to this message:
 Message 366 by Tangle, posted 10-11-2013 1:32 PM Percy has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 361 of 457 (708595)
10-11-2013 9:39 AM
Reply to: Message 360 by NoNukes
10-11-2013 9:15 AM


Re: Environment-driven evolution
Hi NoNukes,
My view of breeding and evolution is that they differ only in the selection pressures. I think Darwin saw it the same way. I suspect you're calling breeding a dead end because it doesn't produce new species, but that's not a limitation of artificial selection. It has more to do with the goals of breeders and the constraints of time for long-lived species. Certainly we have no trouble using artificial selection to produce new species when they're very short-lived.
--Percy

This message is a reply to:
 Message 360 by NoNukes, posted 10-11-2013 9:15 AM NoNukes has replied

Replies to this message:
 Message 362 by NoNukes, posted 10-11-2013 12:22 PM Percy has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 377 of 457 (708668)
10-12-2013 7:55 AM
Reply to: Message 362 by NoNukes
10-11-2013 12:22 PM


Re: Environment-driven evolution
NoNukes writes:
I may have been unclear about that. A breed is not necessarily a dead end, but the process of breeding as practiced by say collie breeders is indeed a dead end. The process is designed to create a specific phenotype and to reject the breeder's idea of unacceptable diversity. A mutation that generates more powerful legs on a collie would get kicked out ot the gene pool by breeders even if such a thing would produce a survival advantage out in the wild.
Right, but again, the only meaningful difference is in the criteria of selection. In nature survival to reproduce is the criteria. In breeding programs pleasing the breeder is the criteria. Both approaches produce greater adaptation to the criteria, which is all that's important.
Yes, but that turns out to make a huge difference...
The huge difference being the resulting phenotypes? How is the difference in phenotypes produced by natural versus artificial selection any more significant than the differences produced by placing a population in the desert versus the rain forest? The specifics of the resultant phenotypes are irrelevant to the central point: selection produces adaptation.
--Percy

This message is a reply to:
 Message 362 by NoNukes, posted 10-11-2013 12:22 PM NoNukes has replied

Replies to this message:
 Message 382 by NoNukes, posted 10-12-2013 11:56 AM Percy has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 378 of 457 (708669)
10-12-2013 8:08 AM
Reply to: Message 366 by Tangle
10-11-2013 1:32 PM


Re: Environment-driven evolution
How is it that the role played by regulatory genes (Hox related or not) in "large evolutionary changes in body morphology...contradicts the neo-Darwinian synthesis?" I don't see it. Sounds like someone trying to puff up the importance of their particular sub-discipline of interest.
--Percy

This message is a reply to:
 Message 366 by Tangle, posted 10-11-2013 1:32 PM Tangle has replied

Replies to this message:
 Message 379 by Tangle, posted 10-12-2013 10:22 AM Percy has seen this message but not replied
 Message 380 by herebedragons, posted 10-12-2013 10:46 AM Percy has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 387 of 457 (708726)
10-13-2013 8:23 AM
Reply to: Message 380 by herebedragons
10-12-2013 10:46 AM


Re: Environment-driven evolution
herebedragons writes:
The way I understand it is that Neo-Darwinism suggests that the accumulation of small changes over long periods of time is sufficient to explain all evolutionary processes.
I don't think the synthesis of Darwin's conception of evolution with genetics is so constraining. It's only a framework for interpreting the evidence, not a set of rules. There's no neo-Darwinian rule that change can only come about through the accumulation of small genetic changes.
So though we do know that offspring in sexual species will be very little changed morphologically from their parents (otherwise they will find no mates), we also know that at the genetic level changes can be massive, such as duplication of entire chromosome sets in some flowering plants, or the incorporation of one cell into another at the beginning of the eukaryotic line.
We are finding that the reality of evolution is much more complicated than we had previously imagined.
In my view there are two forces at work here here. My experience has been that trying to boil down science into simple explanations understandable by laypeople lends an impression that any given science is simpler than the actual scientists themselves believe. And also in all branches of science there is always a large subset who believes the universe is far simpler than it really is, though I think one tends to grow out of this as one grows older.
The pace of scientific discovery has not slowed. Obviously there is much we don't know. It should therefore come as no surprise each time we discover something we do not know, no matter how much the popular press reports on scientific amazement and surprise. In the whole history of science there are few discoveries that actually deserve those adjectives. The Big Bang is one. That continents move is another. That the expansion of the universe is accelerating is yet another. But evo-devo? No.
Its my point too, that the modern understanding of evolutionary processes are way beyond RS + NS.
Again, sounds like puffery to me.
--Percy

This message is a reply to:
 Message 380 by herebedragons, posted 10-12-2013 10:46 AM herebedragons has not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 388 of 457 (708727)
10-13-2013 8:53 AM
Reply to: Message 382 by NoNukes
10-12-2013 11:56 AM


Re: Environment-driven evolution
NoNukes writes:
Percy writes:
Both approaches [artificial versus natural selection] produce greater adaptation to the criteria, which is all that's important.
No Percy, that is not all that is important for this discussion.
But Faith responded to you like this:
Faith in Message 383 writes:
It doesn't matter if a breeder is doing the selecting or the environment is...
Precisely!
Does it make my position more clear if I add that when I think of "breeding" I don't think of just actual breeders of pets and cattle? I think of all types of artificial selection (I did use that term earlier), which means only that the selection choices are made by human beings. The kind of breeding you have in mind where the goal is to maintain the breed is a subset of artificial selection, and it's even just a subset of what breeders do, since sometimes they're creating new breeds, and sometimes they're increasing diversity.
I'm not arguing that there aren't distinctions, simply that they aren't relevant to this discussion, and in fact may be confusing the discussion. One of the errors in Faith's understanding is believing that selection plays at best a minor role in producing new phenotypes, and that simply reducing diversity is sufficient. The evidence from breeding says this is wrong and that selection has primacy.
--Percy

This message is a reply to:
 Message 382 by NoNukes, posted 10-12-2013 11:56 AM NoNukes has replied

Replies to this message:
 Message 389 by NoNukes, posted 10-13-2013 10:40 AM Percy has seen this message but not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 390 of 457 (708735)
10-13-2013 2:15 PM
Reply to: Message 383 by Faith
10-12-2013 2:25 PM


Re: Selection does lead to reduced genetic diversity
Faith writes:
Allele frequencies change randomly in some of these processes, but due to particular selection in NS and domestic breeding, but the allele frequencies alone are enough to make big changes and bring about a new variety whatever the cause.
You keep saying this, and it is as false as ever. The allelic frequencies of the very common alleles that define a species are going to be pretty much the same when one first creates a randomly chosen subpopulation. The only allelic frequencies different in the subpopulation would be those that were uncommon in the parent population. Many of the frequencies of these uncommon alleles will drop from some low percentage like 5% or 3% or 1% all the way down to 0%. This is what accounts for the drop in genetic diversity in a subpopulation.
A change in allelic frequency is necessary to bringing about a phenotypic change in a subpopulation. Without different selection pressures the allelic frequencies will remain about the same as the parent population. Only different selection pressures will cause the allelic frequencies to change.
What are you imagining could cause allelic frequencies to change in the absence of selection pressures? In answering this question, consider a main population that becomes split right down the middle when a river changes course, and assume that the environment remains the same on both sides of the river. Let's say that one of the alleles had a frequency of 95% in the original main population, and that it begins at that level in both subpopulations. What cause of change to allelic frequency could there be that would affect one subpopulation but not the other?
If the selection pressures remain the same then the main contributor to change (aside from drift, which is random and slow) is mutation. The paper AZPaul3 cited was about a chain of lizard subpopulations distributed around the perimeter of a mountain, here's the link:
AZPaul3 already quoted one portion about the arise of new DNA sequences, and here's another portion about the cause of reproductive isolation:
Experimental studies strongly favor this view, showing that mutations in coevolving gene complexes can rapidly cause hybrid incompatibilities in closely related species.
In other words, mutations play a key role in producing reproductive incompatibility, and reproductive incompatibility must be considered the foremost of phenotypic differences in speciation processes.
And if selection pressures on the two populations do become different, then the divergent selection pressures will result in divergent allelic frequencies.
But just removing genetic interflow between two populations in the same environment will do little to produce phenotypic differences, and certainly not in a mere 37 years.
--Percy

This message is a reply to:
 Message 383 by Faith, posted 10-12-2013 2:25 PM Faith has replied

Replies to this message:
 Message 392 by Faith, posted 10-13-2013 4:41 PM Percy has not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 391 of 457 (708736)
10-13-2013 2:59 PM


Contribution of Drift
I was looking for technical articles about differences emerging in small populations of the same species and came across an article about herds of the Jutland breed of cattle. I'm amazed at how often persistence can bring a free copy of an article to light which it at first appears available only for a fee, which was the case with this paper, found beginning at page 75 of this link to the journal:
The abstract says:
The data reflected the impacts of fragmentation and restricted gene flow in breeds with small segregated herds, and revealed the rapid differentiation of herds resulting from genetic drift.
The conclusion says:
Our results further demonstrate the rapid diversification of the Jutland breed herds due to limited gene flow and genetic drift.
The article also describes the contribution of mutations. They checked for allelic stuttering (repeated sequences in a portion of allele), allele drop out, and null alleles (mutation making the gene non-functional) (page 77). Subsequent discussion drops into a level of detail that would be too time consuming for me to attempt to parse.
The article focuses primarily on genetic differences. Most of the research effort seems to have been expended on genetic analysis. But the article does make clear that there a very visible phenotypic differences, for example, this from the introduction:
As a consequence, there are high levels of phenotypic variation among indigenous breeds, a variety of adaptations to local environmental conditions and high fitness under natural conditions (Tapio et al., 2006; Dalvit et al., 2008).
Unfortunately the phenotypic differences are never described, so there is no way to tell if they're as significant as the head and diet changes of the lizards of Pod Mrcaru, but even without this detail I think we have to grant that the phenotypic changes in these lizards could have been due either drift, selection, mutation or, most likely, some combination.
--Percy

Replies to this message:
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Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 406 of 457 (708851)
10-15-2013 3:12 PM
Reply to: Message 404 by Faith
10-15-2013 11:19 AM


Re: Contribution of Drift
Faith writes:
Interesting that all anyone does now is throw accusations at me...
You have a way of sucking people in, even those who have long experience with you, into thinking that a coherent evidence-based discussion with you is possible. Gradually realization sinks in.
The power of your ideas is not based upon what you think of them, but others, and in science discussions their assessments are to a great degree based upon the correspondence to real world evidence. But you don't really care about evidence. You think evidence you don't understand supports your ideas, and you ignore evidence you realize doesn't support your ideas.
--Percy

This message is a reply to:
 Message 404 by Faith, posted 10-15-2013 11:19 AM Faith has replied

Replies to this message:
 Message 409 by Faith, posted 10-15-2013 5:42 PM Percy has not replied

  
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