That sounds about right.
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I havenāt. I will check it out.
Is it available on site?
See here: Comments on McLatchie and Swamidass
I get that. I guess Behe would just include the cases of exaption you mention as a damaged gene turning out useful.
Beheās approach becomes problematic in cases where one gene effects more than one functionā¦ this is not very rare in animalsā¦ Loss of efficiency in one task balanced out by a gain in efficiency in another task done by the same gene.
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That is right. If he dove in to acknowledge these issues and solve them, Iād really be interested to see it. This not, unfortunately, what he did. He does not explain that his argument can be reduced to the absurd, and then explain methodology to avert this. This is required for it to be taken seriously.
Iām not actually surprised because we similar sorts of reasoning in his prior work. Without getting into details, it is common for Behe to put forward two mutually contradictory arguments, and complement one another, and use one argument to defeat the objections to the other. This is is standard strategy. As another example, he simultaneously argues:
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Show me an experiment that demonstrates evolution in the lab.
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Evolutionary experiments in the lab are directed and designed, and canāt be used to demonstrate anything about unguided evolution
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(except when I choose not to apply this objection).
The first request is directly contradicted by the second objection. The third escape hatch is a special pleading. That is part of the rhetorical game. It is entertaining to see ID-bashing neophytes schooled by it. At this point, most scientist well aware of the game, and either donāt want to play or wonāt fall for it this time around. It was a fun trick, but it is just a trick. To make progress, we need Behe to make a clear case without misrepresenting data or modern evoutionary theory.
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However, the overall thrust of his argument seems to be in the step after the adaptation by loss of function happens. (The bigger picture).
Since loss of function adaptations are the norm, the overall set of functions in a genome do not increase overall. One ability is sacrificed for anotherā¦
This leaves one wondering how such a process would help a single celled organism to become multicellularā¦ or a invertebrate to become a vertibrateā¦ the overall set of functions in a lineage is increasing over time from the universal ancestors to modern species (say the polar bear). However, a loss of function kind of evolutionary process will not explain this. It can at best explain a static kind of situation for a lineage where the total no: of functions is more or less constant IMO.
This is the thrust of Beheās argument.
Yes, I agree he has an overall thrust. The point is that the overall thrust lacks a foundation. It is trivially reduced to an absurd, self-refuting argument. We will, also, see it reduced to an absurd argument by ID supporters themselves.
I accept your point about exaptations.
However if empirical data shows that the vast number of Adaptation events involved a compromise in some other function, then it is significant.
What do you think such a trend (if true) would predict? A stasis or a steady increase in complexity.
If true, this would mean that lineages that show a steady increase in complexity have something more going on than adaptation that is causing this trend.
Do you disagree? If so, why?
It would be a really interesting finding, but it would NOT really be a challenge to evolution. There are non adaptive ways to increase function, that are more common.
Adaptive changes are the vanishing minority of changes.
Do you mean neutral evolution here?
If itās non-adaptive, doesnāt that mean any gain of function is purely accidental? (Like the example with the anti-freeze in the fish)
Do you find that problematic?
@John_Harshman ; @Mercer : Do you guys also think the majority of the changes that increase function in organisms are non-adaptive.
Not accidental. Expected. Look at the CNE example I give in the talk. New functions are created by constructive ādevoluitonā.
I do find it to be very problematic for Beheās thesis. I cannot see a way around it.
No, by definition. But a lot of the changes that, in eventual combination with others, increase function are non-adaptive.
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Ok, will look into it and ask doubts after that.
Yes, got itā¦ I wasnāt using function as something that is selected forā¦ but rather as how efficiently a particular job is done (Pls see above discussion for context).
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Here is yours and Behe position that is different. Both of you agree that biochemical activity is lost and another is gained.
but the gain of function is due to loss of that existing biochemical activity. What Behe is saying the gain of function is NOT due to new Functional Coded Elements, Instead, the loss of it
Behe says that any gain of function or as you like the change of function is NOT due to new Functional Coded Elements
suppose you have a ship, which is diving on the calm ocean, and suddenly storm starts, so the enviroment is changed and a ship has to survive not to sink in an new enviroment. The crew of the ship decides to trow heavy weights onborad, now you gain a new function, you adapted in a stormy enviroment and do not sink, but that adaptation come from loss of some stuff from ship,Ship did not gain more efficent navigation in stormy enviroment due to more powerfull engine added.
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Another question I have about Beheās essay has to do with his explanation of how harmful but beneficial mutations will preclude the fixation of beneficial mutations that add or create functionality (or something like that). At face value, it seems intuitive, but it seems to assume that, once any beneficial trait becomes fixed, that natural selection stops. Can anyone make sense of this for me?
Also, it looks to me as if Behe is assuming that the overall ratio of harmful to beneficial mutations is going to be the same as the ratio of ādamagingā to āhelpfulā positively-selected mutations. I donāt know about this, but it seems to me that differences between the two will factor greatly into his depiction of the overwhelming effects of ādamagingā positively-selected mutations.
Feel free to chime in ā¦
It is important to realize Behe argues his case exclusively with words, without any formal models. Attempting to formalize his thesis would very likely yield very divergent models, depending on precisely which quotes are used. It seems he is attempting to make a quantitative argument with qualitative reasoning. I do not think he has even settled many of these details in his mind into a cohesive whole.
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As far as I understand, natural selection depends on reproductive fitness.
Behe seems to be postulating that
a) Breaking of a biochemical function happens faster and much more frequently than forming a new one.
b) Hence solutions to problems are found more quickly by breaking genes.
c) Once a solution is found and is fixed. If a similar solution arises which is caused by a gene gaining biochemical function, it will not give a fitness advantage and hence will not be fixed.
One way to test this would be if there are genes thqt add biochemical function without breaking anything which did not get fixed in the entire population, and if so whether it is made redundant by a gene breaking and providing a similar service.
@Art have you had a chance to read the book yet?