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RE: Documented evolution of new functions and behaviors in bacteria

 
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RE: Documented evolution of new functions and behaviors... - 5/2/2008 2:20:12 PM   
Agahnim

 

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quote:

And you are missing my point; if you are conceding that evolution is untestable because it relies on unknown imagined entities, then it is a substantively less robust theory than it is made out to be.

Do you remember the reason why we’re discussing this? I’m asking you to support your assertion that evolution is impossible because of natural selection not favoring the individual mutations necessary to produce these structures. Whether this one aspect of evolution is testable or not is irrelevant here, and I’m a little surprised to hear this from someone who apparently cares as much as you do about staying on topic.

quote:

I have to say you would be hard pressed to find an example in prehistory where we didn’t have some idea about what the organism ate; and while environments vary greatly, we have a pretty good idea of what the environments and the type of organisms that were around when bats are thought to have first appeared.
[…]
Well, no modern day scenario is going to give us a definitive answer of how it did happen, but it will give us a pretty good idea of what can and cannot happen in terms of the mechanisms involved; certainly moreso than the imaginary musings currently employed by evolutionists.

If you’re willing to consider more than just what’s beneficial to lab mice, then I think it’s possible to make a pretty good case that these mutations would have been useful to the ancestors of bats. I already described this. Longer fingers would have probably been useful for climbing, and skin membranes (without flight muscles) would have been useful for the same thing they’re useful for in flying squirrels.

In order to support your assertion that the evolution of bats’ wings is impossible, you will need to show that these mutations definitely would not have been useful to the ancestors of bats for these functions, or any other functions. Can you?

_____________________________

"I like your Christ. I do not like your Christians. Your Christians are so unlike your Christ." --Mahatma Gandhi
Post #: 176
RE: Documented evolution of new functions and behaviors... - 5/2/2008 2:37:09 PM   
Jhud


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From: Lake Wobegon
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quote:

Do you remember the reason why we’re discussing this? I’m asking you to support your assertion that evolution is impossible because of natural selection not favoring the individual mutations necessary to produce these structures. Whether this one aspect of evolution is testable or not is irrelevant here, and I’m a little surprised to hear this from someone who apparently cares as much as you do about staying on topic.


Well, hey, having dealt pretty decisively with your bacterial examples and your antiviral resistance examples, it’s apparent there isn’t a lot left of the original topic, so if you want to discuss anteaters as well, be my guest. It’s all sort of frosting at this point anyway.

quote:

If you’re willing to consider more than just what’s beneficial to lab mice, then I think it’s possible to make a pretty good case that these mutations would have been useful to the ancestors of bats. I already described this. Longer fingers would have probably been useful for climbing, and skin membranes (without flight muscles) would have been useful for the same thing they’re useful for in flying squirrels


Well, I am willing to consider comparisons to other extant mammals for comparison, especially genetically. I do know that morphologically the structure of a flying squirrel (or colugo, or sugar glider, etc) is nothing like that of a bats; indeed, the opposite in many respects.

But how might I disprove your imagination?

quote:

In order to support your assertion that the evolution of bats’ wings is impossible, you will need to show that these mutations definitely would not have been useful to the ancestors of bats for these functions, or any other functions. Can you?


Well, I think I can show that any case you might imagine is absurd.

_____________________________

Jack

“I mean to live my life an obedient man, but obedient to God, subservient to the wisdom of my ancestors; never to the authority of political truths arrived at yesterday at the voting booth”
William F. Buckley Jr. 1925-2008
Post #: 177
RE: Documented evolution of new functions and behaviors... - 5/2/2008 3:04:26 PM   
gluadys

 

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quote:

ORIGINAL: Jhud
If you mean the bone would lengthen and rip through the skin leaving behind nerve tissue and cartilage, you are right. But it still leaves a mammal with a long forelimb (or digits), and no advantage or support system for having them.


You do not know that there is no advantage. And you have just conceded that there is a support system of skin, circulation, nerves, etc.

quote:

But that is the problem; every 'plausible pathway' (which incidentally is an extremely low bar in term of evidence for a presumed scientific theory, as it is primarily the product of imagination) requires over-simplification; none actually deal with our observation about organisms actually function.


Of course, speculated plausible pathways are products of the imagination; "just so" stories as Stephen Gould called them. And any deficiencies in how they relate to observations of how organisms function must be dealt with. But I think we would both agree that if evolution is true, the organism must be a fully viable functioning organism through the entire trajectory of its history. If it can be shown that there is no possibility of this being the case, you will have finally found an empirical example of ID.

In the meantime, incredulity is not a sufficient reason to reject the evolutionary thesis.

quote:

quote:

Good. I look forward to learning more about it. Now if we could improve your comprehension of evolution, we would really be making progress.


You know, just a guess here, but I was probably an evolutionist long before you cracked a biology text,


Unless you are a grandpa, I doubt that. I was probably an evolutionist before you were born. Note, however, that I am not a scientist. My actual field of professional study is language and literature. And I know more theology than biology. My principal objections to both creationism and ID are theological.


quote:

Well, we have plenty of mice. As we identify the individual modifications to the regulation of genes and apply them to the morphology of a test mammal like a mouse, we should get a pretty good idea of how those specific changes affect even ordinary existence. We will probably be able to test a few changes together. And we can can do so repeatedly. Now this isn't easy science like sitting around in one's office imagining how a bat might have evolved from a ground dwelling mammals, but it is substantive science, to which we can make predictions and draw conclusions based on measurable observations; and as we build up a real body of knowledge here, we should have a pretty good idea of what such changes actually entail instead of imagining predators that we will never know the ecology of.


So, you agree this "real body of knowledge" has not been built up yet and you cannot really come to any definitive conclusions.

Seems you too are into predictions.

Of course, there is nothing wrong with that. Predictions guide how we test hypotheses.

And building up this real body of knowledge is the only long-term way to come to firm conclusions on how evolution works in specific circumstances. It is the only antidote to the all-too-prevalent use of just-so stories.

Now my prediction is that while a real body of knowledge will show us that evolution is a far more complex phenomenon than we have yet grasped, it will also show conclusively that this level of highly complex, co-ordinated change did occur without grasping at an extra-scientific bag of tricks.

I am not an opponent of the concept that intelligence governs evolution. I just think that the intelligence which created this universe knows how to use its capacities without needing to import non-natural mechanisms.
Post #: 178
RE: Documented evolution of new functions and behaviors... - 5/2/2008 3:18:31 PM   
Jhud


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quote:

You do not know that there is no advantage. And you have just conceded that there is a support system of skin, circulation, nerves, etc.


How does one concede that which one never disputed?

quote:

Of course, speculated plausible pathways are products of the imagination; "just so" stories as Stephen Gould called them. And any deficiencies in how they relate to observations of how organisms function must be dealt with. But I think we would both agree that if evolution is true, the organism must be a fully viable functioning organism through the entire trajectory of its history. If it can be shown that there is no possibility of this being the case, you will have finally found an empirical example of ID.


Well, yes, and such observations are better done when we actually deal with the genetics and test the effects of modification to real animals with real genomes rather than engage in evolutionary daydreams. Call me a real skeptic.

quote:

In the meantime, incredulity is not a sufficient reason to reject the evolutionary thesis.


Certainly not, much as the willingness to accept incredible things is no basis for accepting such a theory; which is why I prefer observable evidence.

quote:

Unless you are a grandpa, I doubt that. I was probably an evolutionist before you were born. Note, however, that I am not a scientist. My actual field of professional study is language and literature. And I know more theology than biology. My principal objections to both creationism and ID are theological.


Well I suppose I should differ to the possibility that you have actually watched evolution occur in your lifetime.

My field of study was biology; I reject evolution on scientific grounds.

quote:

So, you agree this "real body of knowledge" has not been built up yet and you cannot really come to any definitive conclusions.


I agree it's just beginning; based on what is already known, it is not a simplistic as you have described.

quote:

Seems you too are into predictions.

Of course, there is nothing wrong with that. Predictions guide how we test hypotheses.


Of course; it's one of the reasons I like ID.

Now my prediction is that while a real body of knowledge will show us that evolution is a far more complex phenomenon than we have yet grasped, it will also show conclusively that this level of highly complex, co-ordinated change did occur without grasping at an extra-scientific bag of tricks.

And do you have a time limit for your prediction to be verified? Or shall we ever consider, like The X Files, the evidence to be 'out there'?

quote:

I am not an opponent of the concept that intelligence governs evolution. I just think that the intelligence which created this universe knows how to use its capacities without needing to import non-natural mechanisms.


Well, I guess what's separates us then is that I think there is evidence to verify that intelligence governed life's development.

_____________________________

Jack

“I mean to live my life an obedient man, but obedient to God, subservient to the wisdom of my ancestors; never to the authority of political truths arrived at yesterday at the voting booth”
William F. Buckley Jr. 1925-2008
Post #: 179
RE: Documented evolution of new functions and behaviors... - 5/3/2008 3:02:35 AM   
Agahnim

 

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quote:

Well, hey, having dealt pretty decisively with your bacterial examples and your antiviral resistance examples, it’s apparent there isn’t a lot left of the original topic, so if you want to discuss anteaters as well, be my guest. It’s all sort of frosting at this point anyway.

I’ve pretty much made the point that I was trying to make with those. I wasn’t really expecting to be able to come up with a “magic bullet” that proves absolutely everything you doubted about evolution in a single example, so what I’ve been doing instead is coming up with a few examples of individual things that you seemed to doubt, such as the existence a mutation that produces a novel ability (the nylon-eating bacteria), and multiple beneficial coding mutations accumulating in a single organism (such as the HIV example).

So the current question is, if all of these individual things are possible, is there any specific aspect of evolution that can be considered impossible? That’s what we’re discussing now.

quote:

Well, I am willing to consider comparisons to other extant mammals for comparison, especially genetically. I do know that morphologically the structure of a flying squirrel (or colugo, or sugar glider, etc) is nothing like that of a bats; indeed, the opposite in many respects.

But how might I disprove your imagination?

I think you’re underestimating the number of possible situations in which a parachute-like structure can be useful for gliding. Remember the fossil of an early bat that I linked you to, whose wing morphology was specifically suited for gliding. Gliding is something it or its ancestors could have done even without flight muscles.

But in any case, you can’t disprove the possibility of these structures having had any kind of use (or what we can “imagine”, as you put it), and that’s sort of my point. One of the premises of Intelligent Design is not just that evolution does not currently have an answer to how certain structures evolved—its premise is that the evolution of a structure like this one is not possible, or at least so statistically improbable that it may as well be impossible, because we can know for certain that natural selection would not have favored any of the individual mutations responsible for it. Are you conceding that because we aren’t able to know what possible advantage these mutations could have provided, this particular premise of ID is unsupportable?

< Message edited by Agahnim -- 5/3/2008 7:51:09 AM >


_____________________________

"I like your Christ. I do not like your Christians. Your Christians are so unlike your Christ." --Mahatma Gandhi
Post #: 180
RE: Documented evolution of new functions and behaviors... - 5/3/2008 7:57:57 PM   
gluadys

 

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quote:

ORIGINAL: Jhud

My field of study was biology; I reject evolution on scientific grounds.


I don't think you have shown what the scientific grounds are. I think what is coming out of molecular biology is putting a real strain on the description of evolution that came out of the modern synthesis (neo-Darwinism) and that is to be expected.

That definition came from a synthesis of Mendel's (and subsequent) work on genetics, the early 20th century work on mutations (not yet understood in terms of DNA) and Darwin's original thesis of natural selection. For various reasons, the study of embryological development made no contribution to the synthesis and it is increasingly evident that this is an area that must be included in any study of how evolution works. And, of course, cracking the structure and coding of DNA, together with the all the subsequent research that has followed, and is revamping our whole understanding of genes and how they work. So, I think we are very much in need of some collaboration that organizes all this new information in a coherent way.

Yet through all this, the basic concept of species change driven by selection, seems to be holding up pretty well. Just as with Darwin's original work, it is not natural selection that seems to be the problem, but determining the origin of what is selected.
Darwin said variation was selected. But he proposed no substantive theory on the origin of variation.
Mendel's work answered another strong objection to Darwin--namely, how novel variations could be preserved, but although Mendel initiated study into how genes interacted, he never thought to address where they came from.
So we get to mutations as the origin of genetic variation.
And now we are digging into exactly what that entails and finding levels of complexity we never dreamed of.

Not to mention the abiogenesis question of the origin of DNA and its information carrying capacity. That's a side issue for evolution per se, but it's a valid question.

The mechanisms and processes that provide something to select need to be understood. But not understanding them is not a scientific objection to evolution.


quote:

And do you have a time limit for your prediction to be verified? Or shall we ever consider, like The X Files, the evidence to be 'out there'?


Will we always have the spectre of the god-of-the-gaps out there? Yes, probably, for since every discovery provokes new questions, I doubt that we will ever have a completely seamless understanding of nature.

But, of course, that doesn't mean that nature is not seamless. I think a seamless nature is more compatible with Christian theology. And I expect that science will find no falsification of a seamless nature. But I do not expect it will fully discover how to knit all the apparently raw edges together.

quote:

Well, I guess what's separates us then is that I think there is evidence to verify that intelligence governed life's development.



I think the universe as a whole is evidence of intelligence. I don't think any bits and pieces of it have special evidentiary power in comparison to others.
Post #: 181
RE: Documented evolution of new functions and behaviors... - 5/5/2008 11:37:44 AM   
Jhud


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quote:

I don't think you have shown what the scientific grounds are. I think what is coming out of molecular biology is putting a real strain on the description of evolution that came out of the modern synthesis (neo-Darwinism) and that is to be expected.


I agree with you here.

quote:

That definition came from a synthesis of Mendel's (and subsequent) work on genetics, the early 20th century work on mutations (not yet understood in terms of DNA) and Darwin's original thesis of natural selection. For various reasons, the study of embryological development made no contribution to the synthesis and it is increasingly evident that this is an area that must be included in any study of how evolution works. And, of course, cracking the structure and coding of DNA, together with the all the subsequent research that has followed, and is revamping our whole understanding of genes and how they work. So, I think we are very much in need of some collaboration that organizes all this new information in a coherent way.


I agree with you here, but I would go farther; I think we need to apply the current principles of the development of information systems and micro-machine engineering as well.

quote:

Yet through all this, the basic concept of species change driven by selection, seems to be holding up pretty well. Just as with Darwin's original work, it is not natural selection that seems to be the problem, but determining the origin of what is selected.
Darwin said variation was selected. But he proposed no substantive theory on the origin of variation.
Mendel's work answered another strong objection to Darwin--namely, how novel variations could be preserved, but although Mendel initiated study into how genes interacted, he never thought to address where they came from.
So we get to mutations as the origin of genetic variation.
And now we are digging into exactly what that entails and finding levels of complexity we never dreamed of.


Again, I generally agree; and not only are we, “finding levels of complexity we never dreamed of”, we are finding the complexity is far more ancient than we ever dreamed of.

quote:

Not to mention the abiogenesis question of the origin of DNA and its information carrying capacity. That's a side issue for evolution per se, but it's a valid question.


I am not so sure it is a ‘side-issue’, as I think that the capabilities of the genome are proving to be quite ancient, and it’s capabilities get pushed back further and further in time, we are realizing that it began with such capabilities, and so we are not simply talking about the origin of the cell, but the origin of the capability of life to develop and sustain itself. And this may very well give us insights that evolution has failed to.

quote:

The mechanisms and processes that provide something to select need to be understood. But not understanding them is not a scientific objection to evolution.


Well, it’s obviously not a support to evolution either. But more than that, I think it allows us to say it is reasonable to put all the options on the table – including that of intelligent causation.

quote:

Will we always have the spectre of the god-of-the-gaps out there? Yes, probably, for since every discovery provokes new questions, I doubt that we will ever have a completely seamless understanding of nature.


Of course not; in fact we know that we never with certainty understand what actually did happen in the past. But it is still reasonable to consider intelligence as a cause.

quote:

I think the universe as a whole is evidence of intelligence. I don't think any bits and pieces of it have special evidentiary power in comparison to others.

This is perhaps where we differ; I see the evidence all the way through from top to bottom.

_____________________________

Jack

“I mean to live my life an obedient man, but obedient to God, subservient to the wisdom of my ancestors; never to the authority of political truths arrived at yesterday at the voting booth”
William F. Buckley Jr. 1925-2008
Post #: 182
RE: Documented evolution of new functions and behaviors... - 5/6/2008 8:35:52 AM   
Agahnim

 

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I was hoping Gluadys would have something to say in response to this, but since she apparently doesn’t, I guess I will.

quote:

Well, it’s obviously not a support to evolution either. But more than that, I think it allows us to say it is reasonable to put all the options on the table – including that of intelligent causation.

I don’t seriously have a problem with considering intelligent causation as a possible explanation for life’s complexity, meaning that if we encounter things that definitely can’t be explained by anything other than intelligent design, we shouldn’t ignore them. What I have a problem with is people claiming that we’re already in a situation where this is the case. As I pointed out in my previous post here, there’s no reason to assume that skin membranes without flight muscles on the ancestors of bats wouldn’t have been useful for gliding. The most that can be said in this case is that until we have more information in this area, we won’t have proof of what process was responsible for this aspect of bats’ anatomy—evolution and intelligent design are both possible explanations.

So while we can certainly “consider” intelligent design as a possible explanation for this, there are several other things that should be considered also. The main one is that the evolutionary explanation for this involves only processes that have been observed happening in the present—novel functions arising as a result of mutations, as in the nylonase example, and then multiple beneficial coding mutations accumulating in a single organism, as in the HIV example. Intelligent design, on the other hand, explains this using a mechanism that has never been observed. It would be reasonable to speculate that an unknown and unobserved mechanism was responsible for something if that thing couldn’t be explained by any known mechanism, but in a situation like this one where known mechanisms are sufficient, this unobserved mechanism that isn’t required in order to explain anything becomes a superfluous entity ruled out by Occam’s Razor.

Please let me know what you have to say about this particular point. When you gave me your list of criteria for accepting evolution as an explanation for life’s diversity, you seemed to be making the point that you would not hold on to Intelligent Design if evolution were shown to be a better explanation. What I’ve described here, and in my previous post, is a different reason why I think evolution is a better theory in terms of explanatory power. So if you still disagree with this, I’d like to know why you do.

_____________________________

"I like your Christ. I do not like your Christians. Your Christians are so unlike your Christ." --Mahatma Gandhi
Post #: 183
RE: Documented evolution of new functions and behaviors... - 5/6/2008 10:30:58 AM   
Jhud


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quote:

I don’t seriously have a problem with considering intelligent causation as a possible explanation for life’s complexity, meaning that if we encounter things that definitely can’t be explained by anything other than intelligent design, we shouldn’t ignore them. What I have a problem with is people claiming that we’re already in a situation where this is the case. As I pointed out in my previous post here, there’s no reason to assume that skin membranes without flight muscles on the ancestors of bats wouldn’t have been useful for gliding. The most that can be said in this case is that until we have more information in this area, we won’t have proof of what process was responsible for this aspect of bats’ anatomy—evolution and intelligent design are both possible explanations.


I guess I have a problem with advancing an argument by means of ‘there is no reason to assume that…’. There is no reason not to assume lots of things; but not assuming something, and reasonably asserting something actually is, are two different things. One does not require positive evidence, the other does. There is no reason to assume evolution couldn’t produce a unicorn. But this isn’t a reason for believing evolution did produce a unicorn – such a thing requires evidence, and until such evidence is produced, then it is reasonable to say evolution produced no unicorns.

There is no evidence that multiple interdependent modifications to the disparate regulatory mechanisms that produce the morphology of a bat can arise both independently and interdependently through gradual incidental modifications of the genome. Indeed, there are lots of problems with this happening, the least of which is that every independent change poses a number of potential problems for the survivability of the organism to which they are occurring. The second of which is that there is no means by which we can both coordinate between the disparate specific changes that are necessary; they are independent genetically, and they are dependent on order of development, and on kinds of development.

So there are good reasons to assert the need for coordination and forethought in this case, and others.

quote:

So while we can certainly “consider” intelligent design as a possible explanation for this, there are several other things that should be considered also. The main one is that the evolutionary explanation for this involves only processes that have been observed happening in the present—novel functions arising as a result of mutations, as in the nylonase example, and then multiple beneficial coding mutations accumulating in a single organism, as in the HIV example. Intelligent design, on the other hand, explains this using a mechanism that has never been observed. It would be reasonable to speculate that an unknown and unobserved mechanism was responsible for something if that thing couldn’t be explained by any known mechanism, but in a situation like this one where known mechanisms are sufficient, this unobserved mechanism that isn’t required in order to explain anything becomes a superfluous entity ruled out by Occam’s Razor.


See, this is where evolution really fails; in neither case, either the nylonase example, nor the HIV example, can those kinds of changes be translated to the necessary changes required to modify the morphology of a mammal to be more bat-like. In fact, we have done this experimentally, and they are different processes. A quick indicator of this is that one can induce through selective pressures the changes in bacteria and viruses, repeatedly – and when those pressures are removed, so to goes the change. One cannot however induce through selective pressures these changes in the morphology of a mammal and get more ‘battiness’ – and once those changes are induced through intelligent means, there is no indication they simply revert. So the processes appear to be quite different, regardless of Occam’s.

_____________________________

Jack

“I mean to live my life an obedient man, but obedient to God, subservient to the wisdom of my ancestors; never to the authority of political truths arrived at yesterday at the voting booth”
William F. Buckley Jr. 1925-2008
Post #: 184
RE: Documented evolution of new functions and behaviors... - 5/6/2008 11:05:55 AM   
Agahnim

 

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quote:

There is no evidence that multiple interdependent modifications to the disparate regulatory mechanisms that produce the morphology of a bat can arise both independently and interdependently through gradual incidental modifications of the genome. Indeed, there are lots of problems with this happening, the least of which is that every independent change poses a number of potential problems for the survivability of the organism to which they are occurring. The second of which is that there is no means by which we can both coordinate between the disparate specific changes that are necessary; they are independent genetically, and they are dependent on order of development, and on kinds of development.

So there are good reasons to assert the need for coordination and forethought in this case, and others.

See, this is what I was trying to discuss with you in post #180, and you didn’t reply to it. When we get into the actual changes that are involved, the argument you’re using—“every independent change poses a number of potential problems for the survivability of the organism to which they are occurring”—doesn’t hold up. You keep saying this, and then when I point out how these changes could have actually been useful, you don’t have anything to say in response. Are you going to support your assertion that we can know for certain that these changes would have posed problems to the organisms’ survivability, or attempt to address my point about why we can’t know this?

quote:

A quick indicator of this is that one can induce through selective pressures the changes in bacteria and viruses, repeatedly – and when those pressures are removed, so to goes the change. One cannot however induce through selective pressures these changes in the morphology of a mammal and get more ‘battiness’ – and once those changes are induced through intelligent means, there is no indication they simply revert. So the processes appear to be quite different, regardless of Occam’s.

You’re completely making up this idea that changes that are the result of intelligence don’t revert—since these types of changes have never been observed, there’s no way to say what happens with them in this respect, if they occur at all. In any case, if evolution was responsible for the origin of animals such as bats, the selective pressure responsible for the changes in them wouldn’t have appeared and then suddenly disappeared; it would have been an ongoing process. So this particular objection you’re raising isn’t a problem for evolution either.

It’s also somewhat off-topic, since what we’ve been discussing is whether natural selection could have favored the individual mutations responsible for flight in bats. I’ve been trying to get you to either support your assertion that we’re able to know for certain that it wouldn’t have, or admit that these mutations could have been favored by natural selection, so the origin of bats is possible via evolution and any design process proposed for them is a superfluous entity.

It’s a fairly simple point—please don’t evade it.

_____________________________

"I like your Christ. I do not like your Christians. Your Christians are so unlike your Christ." --Mahatma Gandhi
Post #: 185
RE: Documented evolution of new functions and behaviors... - 5/6/2008 11:31:26 AM   
Jhud


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From: Lake Wobegon
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quote:

See, this is what I was trying to discuss with you in post #180, and you didn’t reply to it. When we get into the actual changes that are involved, the argument you’re using—“every independent change poses a number of potential problems for the survivability of the organism to which they are occurring”—doesn’t hold up. You keep saying this, and then when I point out how these changes could have actually been useful, you don’t have anything to say in response. Are you going to support your assertion that we can know for certain that these changes would have posed problems to the organisms’ survivability, or attempt to address my point about why we can’t know this?


Well, again, you have posited scenarios where you imagine they can be useful, but as I have pointed out repeatedly, this isn’t a scientific assertion; unless you can demonstrate those useful changes in a model animal, your assertions have no basis in fact.

quote:

You’re completely making up this idea that changes that are the result of intelligence don’t revert—since these types of changes have never been observed, there’s no way to say what happens with them in this respect, if they occur at all.


There are numerous examples at this point in history where we modify genomes in organisms and see them persist through numerous generations, everything from bacteria that are designed to produce certain necessary pharmaceuticals, to crops that have genetically induced pest resistance, to the modification of fish for aquaculture.

quote:

In any case, if evolution was responsible for the origin of animals such as bats, the selective pressure responsible for the changes in them wouldn’t have appeared and then suddenly disappeared; it would have been an ongoing process. So this particular objection you’re raising isn’t a problem for evolution either.


My point, which you seem not to have understood, was the comparison of certain genetic changes, like those of the ‘nylonase’ organism and the HIV virus, and the required changes to produce bat morphology; are significantly different mechanisms and effects. One doesn't demonstrate the other.

quote:

It’s also somewhat off-topic, since what we’ve been discussing is whether natural selection could have favored the individual mutations responsible for flight in bats. I’ve been trying to get you to either support your assertion that we’re able to know for certain that it wouldn’t have, or admit that these mutations could have been favored by natural selection, so the origin of bats is possible via evolution and any design process proposed for them is a superfluous entity.


I think there is no evidence that the numerous and specific changes that are required to induce the bat morphology are individually beneficial, and for those changes which we have induced and observed (like forearm and digit lengthening, two separate changes) no benefit was in evidence. The assertion that they can happen then is really a fantastic claim, one that would require evidence, the burden of which is on the person making the claim (that would be you).

Of course ongoing research may change this; but as it stands, I think my position is significantly more reasonable than yours, and more elegant.

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Post #: 186
RE: Documented evolution of new functions and behaviors... - 5/6/2008 12:09:22 PM   
Method

 

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quote:

ORIGINAL: Jhud
Well, again, you have posited scenarios where you imagine they can be useful, but as I have pointed out repeatedly, this isn’t a scientific assertion; unless you can demonstrate those useful changes in a model animal, your assertions have no basis in fact.


You have posited scenarios where you imagine that they can not be useful. Where is your support?

quote:

There are numerous examples at this point in history where we modify genomes in organisms and see them persist through numerous generations, everything from bacteria that are designed to produce certain necessary pharmaceuticals, to crops that have genetically induced pest resistance, to the modification of fish for aquaculture.


I have actually done this work in E. coli. For my expression plasmids I have to incorporate antibiotic resistance in the plasmid to keep strong selective pressure on the E. coli to keep the plasmid. Once that selective pressure is removed the E. coli start to get rid of the plasmid.

Other systems may differ, but that has been my experience with a select subset of genetically modified organisms.

quote:

My point, which you seem not to have understood, was the comparison of certain genetic changes, like those of the ‘nylonase’ organism and the HIV virus, and the required changes to produce bat morphology; are significantly different mechanisms and effects. One doesn't demonstrate the other.


Then perhaps you should complain about those who use the bacterial flagellum to discount vertebrate evolution.

quote:

I think there is no evidence that the numerous and specific changes that are required to induce the bat morphology are individually beneficial, and for those changes which we have induced and observed (like forearm and digit lengthening, two separate changes) no benefit was in evidence. The assertion that they can happen then is really a fantastic claim, one that would require evidence, the burden of which is on the person making the claim (that would be you).


The assertion that they can happen is the hypothesis which is being tested further. The ID claim, however, is a dogmatic statement. It states that no such changes can or have existed, and it states this without any evidence. I fully understand that a universal negative is impossible to prove, but then why does ID rely on it?

quote:

Of course ongoing research may change this;


But how can it if no possible mutations exist as ID states? The scientists should just pack their bags and call it a day, right?
Post #: 187
RE: Documented evolution of new functions and behaviors... - 5/6/2008 12:36:51 PM   
Jhud


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quote:

You have posited scenarios where you imagine that they can not be useful. Where is your support?


I discussed this at length in my designing a bat thread. Of the two currently induced modifications that lengthen forearms and lengthen digits, neither presents a particularly beneficial modification by itself.

quote:

I have actually done this work in E. coli. For my expression plasmids I have to incorporate antibiotic resistance in the plasmid to keep strong selective pressure on the E. coli to keep the plasmid. Once that selective pressure is removed the E. coli start to get rid of the plasmid.

Other systems may differ, but that has been my experience with a select subset of genetically modified organisms.


I am not saying we can’t induce changes that don’t persist, in fact any change that is energy consumptive which doesn’t present a distinct advantage in an environment wouldn’t persist, I am simply pointing out that the cases utilized (nylonase and antiviral resistance) present repeatable inducible examples that only persist in highly selective environments; there is no indication that they are persistent in a population or lead to a separate evolutionary pathway. This is obviously quite different then the changes necessary for the development of a type of bat from gradual incremental modifications.

quote:

Then perhaps you should complain about those who use the bacterial flagellum to discount vertebrate evolution.


Perhaps, but I think the example is sufficient as an example which contradicts certain evolutionary notions in its own right.

quote:

The assertion that they can happen is the hypothesis which is being tested further. The ID claim, however, is a dogmatic statement. It states that no such changes can or have existed, and it states this without any evidence. I fully understand that a universal negative is impossible to prove, but then why does ID rely on it?


The ID claim is a statement that is wholly falsifiable; if ‘further testing’ reveals nothing to the contrary, then it would seem to be a claim that withstands scrutiny, like most good scientific claims.

quote:

But how can it if no possible mutations exist as ID states? The scientists should just pack their bags and call it a day, right?


Of course not; the attempted falsification of scientific statements is an important endeavor in science; many attempts were made to falsify the claim by germ theory that living organisms do not spontaneously arise – of course, eventually all failed, and it become inestimably reasonable to dismiss the idea of spontaneous generation.

That being said, I don't know where you get the idea that ID claims, "no possible mutations exist"; that is of course not a claim of ID.

< Message edited by Jhud -- 5/6/2008 1:20:11 PM >


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“I mean to live my life an obedient man, but obedient to God, subservient to the wisdom of my ancestors; never to the authority of political truths arrived at yesterday at the voting booth”
William F. Buckley Jr. 1925-2008
Post #: 188
RE: Documented evolution of new functions and behaviors... - 5/6/2008 12:46:49 PM   
drmark

 

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quote:

I have actually done this work in E. coli. For my expression plasmids I have to incorporate antibiotic resistance in the plasmid to keep strong selective pressure on the E. coli to keep the plasmid. Once that selective pressure is removed the E. coli start to get rid of the plasmid.
Method, is this because the plasmids conferring resistance are actually harmful to the "wild-type" organism living without exposure to antibiotic?

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Post #: 189
RE: Documented evolution of new functions and behaviors... - 5/6/2008 12:51:51 PM   
DanJames


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quote:

ORIGINAL: drmark

quote:

I have actually done this work in E. coli. For my expression plasmids I have to incorporate antibiotic resistance in the plasmid to keep strong selective pressure on the E. coli to keep the plasmid. Once that selective pressure is removed the E. coli start to get rid of the plasmid.
Method, is this because the plasmids conferring resistance are actually harmful to the "wild-type" organism living without exposure to antibiotic?


I was going to ask the same thing. Methods to allow bacteria to exist in the presence of antibiotics are either very costly or damaging to bacteria. I always have to roll my eyes when I hear about these "superbugs" on TV. As if by using antibacterial drugs is creating a race of bacteria that are going to wipe us out because they're resistant to everything.
Post #: 190
RE: Documented evolution of new functions and behaviors... - 5/6/2008 1:17:19 PM   
Method

 

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quote:

ORIGINAL: drmark
Method, is this because the plasmids conferring resistance are actually harmful to the "wild-type" organism living without exposure to antibiotic?


If the plasmids were harmfull then I wouldn't be able to induce expression of the protein. In the case of most leaky inducible expression systems (e.g. pET14), 50% of the expressed protein in the bacteria is the protein of interest. You have to use tightly regulated expression systems to express toxic proteins (e.g. pBAD), and even then you will not express that much before the bacteria dies.

The resistance gene itself is usually an ampicillin resistance gene. I believe it's a simple beta-lactamase gene which isn't a stress on the bacteria at all. The greatest stress on the bacteria is the stress on resources. In leaky systems there is a low level of constituitive expression of a protein that is of no use to the bacteria.

So the idea that designed genetic components persist is not entirely true. I was simply citing an exception.
Post #: 191
RE: Documented evolution of new functions and behaviors... - 5/6/2008 1:21:38 PM   
Method

 

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quote:

ORIGINAL: DanJames
I was going to ask the same thing. Methods to allow bacteria to exist in the presence of antibiotics are either very costly or damaging to bacteria. I always have to roll my eyes when I hear about these "superbugs" on TV. As if by using antibacterial drugs is creating a race of bacteria that are going to wipe us out because they're resistant to everything.


In the case of ampicillin resistance in this bacteria the costs are very low. It only requires one exogenous enzyme, a beta-lactamase. This enzyme does not interfere in any bacterial metabolic pathways except for the resources needed to trascribe and translate the enzyme.

As to superbugs, they are a risk to human health but are not a trheat to wipe out humans across the globe. So far, we are producing new and novel antibiotics that are keeping us ahead of the evolutionary curve. These new drugs are often withheld as last resorts instead of a first line defense. This is because doctors want to limit the bacterial exposure in order to prevent widespread resistance. Hopefully, drug companies will continue to stay ahead of these superbugs (e.g. MRSA).
Post #: 192
RE: Documented evolution of new functions and behaviors... - 5/6/2008 1:23:41 PM   
drmark

 

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quote:

If the plasmids were harmfull then I wouldn't be able to induce expression of the protein.
Are you sure about that? The sickle cell protein can be readily induced to express in a population exposed to endemic malaria, even though one-fourth of the offspring of heterozygous parents will die prematurely. Do you not consider premature death harmful?

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Post #: 193
RE: Documented evolution of new functions and behaviors... - 5/6/2008 2:03:50 PM   
Method

 

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quote:

ORIGINAL: drmark

quote:

If the plasmids were harmfull then I wouldn't be able to induce expression of the protein.
Are you sure about that? The sickle cell protein can be readily induced to express in a population exposed to endemic malaria, even though one-fourth of the offspring of heterozygous parents will die prematurely. Do you not consider premature death harmful?


Hemoglobin S is expressed regardless of the presence of malaria. It is constituitively expressed. Expression plasmids used in molecular biology are inducible. That is, by adding a chemical to the culture it will turn the expression system on. For most expression systems, that chemical is isopropyl-beta-D-thiogalactopyranoside (IPTG). You grow the bacteria to early log phase and then add IPTG which turns on expression of the gene of interest. You let the bacteria go for another 4 hours, harvest the bacteria, lyse them, and then harvest your protein. Modern expression systems also put a 6xhistidine tag on your protein which makes it possible to purify the protein on a nickel chelating column.
Post #: 194
RE: Documented evolution of new functions and behaviors... - 5/6/2008 2:26:03 PM   
gluadys

 

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quote:

ORIGINAL: Jhud

quote:

I don't think you have shown what the scientific grounds are. I think what is coming out of molecular biology is putting a real strain on the description of evolution that came out of the modern synthesis (neo-Darwinism) and that is to be expected.


I agree with you here.


So far so good.

quote:

quote:

That definition came from a synthesis of Mendel's (and subsequent) work on genetics, the early 20th century work on mutations (not yet understood in terms of DNA) and Darwin's original thesis of natural selection. For various reasons, the study of embryological development made no contribution to the synthesis and it is increasingly evident that this is an area that must be included in any study of how evolution works. And, of co