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Author Topic:   Criticizing neo-Darwinism
Dr Adequate
Member
Posts: 12751
Joined: 07-20-2006
Member Rating: 2.2


Message 301 of 309 (594331)
12-03-2010 1:17 AM
Reply to: Message 300 by Bolder-dash
12-03-2010 12:39 AM


Re: A Statement from the Atheist Front
Oh, so this is what intellectualism looks like?

Hmm...I'll take a pass then.

Surely to say that you will take a pass on something should properly imply that you have it as an option.

As it is, you're like a quadriplegic person announcing that he'll "take a pass" on dancing.


This message is a reply to:
 Message 300 by Bolder-dash, posted 12-03-2010 12:39 AM Bolder-dash has responded

Replies to this message:
 Message 303 by Bolder-dash, posted 12-03-2010 1:47 AM Dr Adequate has responded

  
Omnivorous
Member
Posts: 3355
From: Adirondackia
Joined: 07-21-2005
Member Rating: 1.9


Message 302 of 309 (594334)
12-03-2010 1:29 AM
Reply to: Message 300 by Bolder-dash
12-03-2010 12:39 AM


The snark stops here
BD writes:

Oh, so this is what intellectualism looks like?

No, that is what a fact-based expression of contempt looks like.

{I'm letting Dr Adequate get by this time, just because that seems to be exceptionally eloquent snark (still, he is pushing his luck). But no snark dog pile. Further snark may trigger more extreme AMoose reactions. - Adminnemooseus}

Edited by Adminnemooseus, : Hide and comment.

Edited by Adminnemooseus, : Change subtitle.


This message is a reply to:
 Message 300 by Bolder-dash, posted 12-03-2010 12:39 AM Bolder-dash has not yet responded

    
Bolder-dash
Member (Idle past 66 days)
Posts: 983
From: China
Joined: 11-14-2009


Message 303 of 309 (594339)
12-03-2010 1:47 AM
Reply to: Message 301 by Dr Adequate
12-03-2010 1:17 AM


Re: A Statement from the Atheist Front
Well, don't go lacing up your slippers and pressing your tutu just yet there A.
This message is a reply to:
 Message 301 by Dr Adequate, posted 12-03-2010 1:17 AM Dr Adequate has responded

Replies to this message:
 Message 304 by Dr Adequate, posted 12-03-2010 2:00 AM Bolder-dash has not yet responded

  
Dr Adequate
Member
Posts: 12751
Joined: 07-20-2006
Member Rating: 2.2


Message 304 of 309 (594342)
12-03-2010 2:00 AM
Reply to: Message 303 by Bolder-dash
12-03-2010 1:47 AM


Re: A Statement from the Atheist Front
This post has been edited out of consideration for Adminnemooseus. I shall have other opportunities to mock Bolder-dash.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 303 by Bolder-dash, posted 12-03-2010 1:47 AM Bolder-dash has not yet responded

  
Admin
Director
Posts: 11426
From: EvC Forum
Joined: 06-14-2002
Member Rating: 1.3


Message 305 of 309 (594372)
12-03-2010 9:05 AM


Moderator Warning
To All,

I know resisting temptation can sometimes be a significant challenge, but the main discussion forums at EvC Forum are not for taking potshots at the other side. They're for serious discussion of specific topics. If you're not constructively moving discussion of the topic forward, please do not post.

When you cannot resist the urge to go off the reservation Forum Guidelines-wise, please find a thread in Free For All or at least Coffee House.


--Percy
EvC Forum Director

    
herebedragons
Member
Posts: 646
From: Michigan
Joined: 11-22-2009
Member Rating: 2.3


Message 306 of 309 (597199)
12-20-2010 11:01 AM
Reply to: Message 3 by nwr
03-20-2006 10:08 PM


Hi nwr,

I know this is an old thread, but I ran across it the other day and liked your ideas. I agree that neo-darwinismin is an inadequate explanation for evolution, but at this point my reasons amount to little more than personal incredulity, which I realize is not an adequate argument to win a debate. However it is good enough for me to hesitate to make something part of my belief system. I don't necessarily have ambitions to develop my own formal theory, as you are doing, but I would like to come to some conclusions regarding my own personal beliefs and try to reconcile some conflicting ideals.

So, I would like to ask you some questions about your point of view and to clarify your position on a few things.

Message 11: To me, this does seem to be a problem in the neo-Darwinian account, although I don't see a problem in the biology.

Message 12: But if neodarwinism were a good model, then you should not have to keep appealing to the biology to help the model over its weak points.

This is the first thing I am unclear on; what do you mean by "biology" in this context? Are you meaning that when the theory is insufficient to explain a particular evolutionary feature, then an 'add-on' is needed? As an example, RM + NS + Time does not very well explain why placental and marsupial animals have evolved strikingly similar characteristics. So we have termed it "convergent evolution" (which I realize has now become part of the theory). So, the theory doesn't "predict" convergent evolution, so we "appeal to the biology" to explain it. Is that a good example of what you mean by "appeal to the biology"? If it was just one or two of these amendments, no big deal; but when there is so many ... I wonder if it is time to adjust the model.

Obviously no theory is going to explain everything perfectly, so how much predictive power do you expect from neo-darwinism? I personally get frustrated with explanations that are basically RM + NS + Time. IMO this amounts to no better explanation than God-did-it.

Message 3: That's where it becomes downright implausible. The neo-Darwinistic account is one of gradual change. The arguments about irreducible complexity arise because gradual change does not plausibly lead to very complex structures. The biology shows how complex structures can arise, but the gradualism of the neo-Darwinist model seems to argue against it.

This is the aspect that I have had the hardest time coming to terms with: gradualism. Although I can see gradualism working in certain cases, I don't believe it is what we actually observe. Organisms appear fully functional with novel features intact and operational. An example is the Italian Wall Lizard that evolved a new and novel feature (the cecal valve) in about 30 generations from a founding population of 5 breeding pairs! I have been unable to find any follow up work on this discovery that draws conclusions about how this novel feature actually evolved, but it seems unreasonable that this cecal valve evolved in gradual steps in such a short time. Instead, the cecal valve appears fully functional and operational.

http://www.sciencedaily.com/...ases/2008/04/080417112433.htm

Message 13: It predicts punctuated equilibria as a significant mode of speciation. It predicts that novelty will arise.

You seem to advocate PE as a major factor in development of novel features. I believe that neo-darwinism has rejected PE in favor of gradualism or at least relegated it to a very minor role. I am unclear as to why this is, I would guess lack of mechanism. On the surface it makes sense to me and seems to match what we observe better. Organisms are relatively unchanging until environmental conditions require a change or offer some benefit to the organism. Then change is rather rapid, just as in the Wall Lizards.

What is not clear is how changes could accumulate in regions of the DNA that are not being expressed and therefore not being selected for. (I believe I read you proposing such a scenario, but I could not find the quote when I went back to quote it - must have been in another thread) So how do you propose that beneficial mutations can accumulate without selection? That is what would have to happen, right? Back to the Wall Lizards ( I know I keep using the same example but its a good one ) The beneficial mutations would have been accumulating before they were trans-located and when the conditions changed, they expressed these changes. It seems improbable that just the right mutations would have occurred.

Well, I guess thats enough for now.

Just to be clear, I am not arguing for or against anything here, I am just looking to discuss my doubts of neo-darwinism with someone sensible and as you know, doubts are not very well received. Perhaps being a fellow doubter, we could have a decent discussion about this.

Edited by Admin, : Shorten long link.

Edited by Admin, : Fixed long link again.


This message is a reply to:
 Message 3 by nwr, posted 03-20-2006 10:08 PM nwr has responded

Replies to this message:
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nwr
Member
Posts: 5156
From: Geneva, Illinois
Joined: 08-08-2005


Message 307 of 309 (597248)
12-20-2010 3:04 PM
Reply to: Message 306 by herebedragons
12-20-2010 11:01 AM


herebedragons writes:
So, I would like to ask you some questions about your point of view and to clarify your position on a few things.

I did post more about this at another site, during a period when I had been suspended at evcforum. Perhaps you might want to take a look at that.

I should add that usage of the other site has dropped to the point where I'm not at all sure that it's future existence is certain. So you might want to look while you can.

I should add that I am not a biologist. I do study human cognition and human learning, so my ideas on evolution partly reflect my looking at it as a learning system.

nwr writes:
You can account for the novelty by appealing to the biology. But if neodarwinism were a good model, then you should not have to keep appealing to the biology to help the model over its weak points.
herebedragons writes:
This is the first thing I am unclear on; what do you mean by "biology" in this context?

On rereading, I guess that was a little unclear.

Let me start with an analogy using physics. Suppose a critic of relativity were to say "relativity implies that x happens, but it doesn't." I would expect the physicists to respond with empirical data showing that it does happen, or with an argument showing that the critic has misunderstood the theory.

Now, instead, suppose that the critic says "y happens, but is not explained by the theory of relativity." Then, in that case, I would expect the physicist to reply with details of how the theory actually does explain it (or with an admission that the theory doesn't explain everything and this is outside what it is expected to explain). What I would not expect, would be for the physicist to respond with empirical evidence that y actually does happen. For that kind of evidence based reply would seem to be begging the question that was asked.

Back to biology. Behe raises the issue of the flagellum, and says that neo-Darwinism does not explain it. Most of the response that I have seen have been of the form of empirical evidence that the kind of structure Behe says is irreducibly complex actually does arise. Well that's the same kind of question begging. The answer should have been in form of the details as to how the theory shows that this kind of irreducible complexity can arise.

The problem, as I see it, is this: The neo-Darwinian account of evolution is a highly mechanistic account. Mechanism works pretty well for explanations in physics, but it does not work very well in biology. It seems to me that biology needs a notion of "purpose" in its explanations. There's currently an interesting discussion at John Wilkins' blog. Most of the discussion is in the comments, rather than in the original post. It is on the question of whether the language of teleology (purpose directed activity) is being inappropriately used in discussions of evolution. I think you would have to agree, from that discussion, that people find it hard to avoid teleological language. Some of the critics of evolution talk about "Darwinian fairy tales", as a way of expressing their cynicism about some of the teleological assumptions that seem to be implicit in a lot of neo-Darwinian explanation.

What I was trying to do in my alternative theory, was turn things upside down. The existing view is one that describes evolution as a mechanistic and purposeless reality acting on apparently helpless biological organisms, and shaping them for fitness. I wanted to reverse that, and have it a theory of biological organisms acting on themselves. That allows assumptions of purposeful (but not conscious) action, such as a population modifying itself so as to increase the chances that the population will persist in spite of changes to the environment.

herebedragons writes:
Organisms appear fully functional with novel features intact and operational.

I don't think that's particularly surprising, even on a neo-Darwinian account.

herebedragons writes:
An example is the Italian Wall Lizard that evolved a new and novel feature (the cecal valve) in about 30 generations from a founding population of 5 breeding pairs!

That's an interesting example. Thanks for the link.

herebedragons writes:
I have been unable to find any follow up work on this discovery that draws conclusions about how this novel feature actually evolved, but it seems unreasonable that this cecal valve evolved in gradual steps in such a short time. Instead, the cecal valve appears fully functional and operational.

You have to keep in mind that sexual reproduction involves recombinant DNA (combining DNA from both parents). It is quite possible that the genetic innovation required for this cecal valve was already present in the population, though only infrequently expressed in the phenotype (the observable traits). If the new trait was not particularly advantageous, then it might show up only occasionally in individuals. Once these lizards were moved to a new environment, it might have happened that the new trait was particularly beneficial there. So those with the new trait would expand their population, perhaps almost explosively, as they start to exploit a new niche for which they happen to be well suited. And, very quickly, that new trait would become dominant in the resulting population.

herebedragons writes:
You seem to advocate PE as a major factor in development of novel features.

I wouldn't put it that way. Rather, I see PE as an expected phenomenon. In the previous paragraph, I mentioned the almost explosive growth of a population that happened to be well suited to a new niche. And it is that kind of "almost explosive" growth that I would expect to show up as punctuated equilibrium. We need to distinguish between the genetics, and the expressed traits. We should expect the genetic changes to be gradual, but the change in expressed traits could be far more rapid in some circumstances.

herebedragons writes:
I believe that neo-darwinism has rejected PE in favor of gradualism or at least relegated it to a very minor role.

You hear less about it since the death of Stephen Gould. But it still has proponents. One of them is Larry Moran, who sometimes blogs about the role of contingency (as opposed to selection).

herebedragons writes:
What is not clear is how changes could accumulate in regions of the DNA that are not being expressed and therefore not being selected for.

They are not being selected for. But they are also not being negatively selected, which is why they can accumulate without selection pressure limiting them. But some of those genes can be transposed into coding parts of the DNA, so they could be a potential reservoir of variability.


Jesus was a liberal hippie
This message is a reply to:
 Message 306 by herebedragons, posted 12-20-2010 11:01 AM herebedragons has not yet responded

Replies to this message:
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Percy
Member
Posts: 13217
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.1


Message 308 of 309 (597280)
12-20-2010 6:00 PM
Reply to: Message 307 by nwr
12-20-2010 3:04 PM


nwr writes:

Back to biology. Behe raises the issue of the flagellum, and says that neo-Darwinism does not explain it. Most of the response that I have seen have been of the form of empirical evidence that the kind of structure Behe says is irreducibly complex actually does arise. Well that's the same kind of question begging. The answer should have been in form of the details as to how the theory shows that this kind of irreducible complexity can arise.

The responses I've seen describe an array of organisms with flagellum-like structures that range from "no flagellum capability at all" all the way up to "a lot of flagellum capability", illustrating that flagella aren't the only structures of this class that are advantageous and that organisms with flagella-like structures that do not behave like flagella are not uncompetitive.

It is quite possible that the genetic innovation required for this cecal valve was already present in the population...

If it wasn't already present in the population then this is an example of evolution producing advantageous random mutations at an impossible rate. It would be very strong evidence that there are very significant processes at work of which we are yet unaware. Seems unlikely.

The article I read about this (http://www.sciencedaily.com/...ases/2008/04/080417112433.htm) said that the daughter lizard population was genetically identical to the parent population, but if that were really true then the cecal valves would have to be due to environment. One would expect that at a minimum there would be allele frequency differences between parent and daughter populations, so I don't really trust that article. But anyway, one of the scientists is quoted saying, "These structures actually occur in less than 1 percent of all known species of scaled reptiles," so your surmise that the genes for cecal valves were already present in the lizards but unexpressed seems likely.

--Percy


This message is a reply to:
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Replies to this message:
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Wounded King
Member (Idle past 530 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 309 of 309 (597282)
12-20-2010 6:17 PM
Reply to: Message 308 by Percy
12-20-2010 6:00 PM


The article I read about this (http://www.sciencedaily.com/...ases/2008/04/080417112433.htm) said that the daughter lizard population was genetically identical to the parent population

Another stunning piece of science journalism . What were essentially identical were the mitochondrial 12S rDNA and 16S rDNA sequences.

TTFN,

WK


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