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Author | Topic: How do we know its irreducible? | |||||||||||||||||||
Nic Tamzek Inactive Member |
Regarding the origin of eukaryotic cilia/flagella, as well as bacterial flagella and archaeal flagella, you may find this page helpful:
Evolution of flagella - Wikipedia I wrote it up at Wikipedia kinda to try it out and to get the info out there, but it really should be turned into a t.o. FAQ. Ian Musgrave has also updated his page:Page not found | Faculty of Health and Medical Sciences | University of Adelaide (note that this is a new link also) The Thornhill and Ussery article is available in web form here:http://www.cbs.dtu.dk/staff/dave/JTB.html nic
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Nic Tamzek Inactive Member |
Hi Ahmad,
What if I told you that Mike Gene: 1) Has admitted that IC is, at least in some cases, readily accessible to Darwinian evolution -- e.g., the case of the PCP degradation pathway? 2) And that he similarly accepts, or at least doesn't dispute, the evolution of some very complex and (according to Behe) IC systems, like blood-clotting and the immune system? Kinda takes the wind out of the IC argument, doesn't it? nic
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Nic Tamzek Inactive Member |
PS: If you want to see a large number of IDists getting pasted on the immune system question, check out this thread at ISCID:
Organisms using GAs vs. Organisms being built by GAshttp://www.iscid.org/ubb/ultimatebb.php?ubb=get_topic;f=6... And, if the immune system can evolve naturally, why should we be impressed by the flagellum? nic
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Nic Tamzek Inactive Member |
quote: Like I said, he thinks IC can evolve. Behe was wrong. He then sets up a sub-category of IC which he thinks is impossible/very improbable to evolve, called IC machines. But this is clearly a retreat from Behe's position. The PCP degradation has three required parts. Non-degradors only have two. Yet it evolved anyhow, and quite recently (PCP is an artifical pesticide). Read that ISCID thread, I think that Mike Gene may have given us his position on the immune system again in the thread. He certainly didn't defend Behe, Dembski, Nelson et al., even though he is probably the person who knows more about it that any of them. nic
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Nic Tamzek Inactive Member |
Ahmad,
quote: IC is IC, isn't it? Anything with multiple parts required can't (according to Behe) function without those multiple parts, therefore (according to Behe) the function cannot be reached gradually because you need all the parts. I don't see how being a metabolic pathway makes any difference, if it's an IC metabolic pathway. Some metabolic pathways have only one required part (at least hypothetically) -- e.g., the AMP biosynthesis pathway is Behe's example in chapter 7 (p. 140 starting) -- and are therefore not technically IC according to Behe: "[t]hey do not necessarily require several parts to function" (p. 142). But some metabolic pathways (particularly that break down toxins through several toxic intermediate steps, e.g. the PCP degradation pathway) do require several parts to function and are therefore IC. But they can evolve anyway, apparently well within human lifetimes.
quote: How is the blood clotting cascade so radically distinct from a metabolic pathway? And of course, Behe includes the lactose metabolism pathway as IC -- note that it's a metabolic pathway -- as proven by the vociferous debate that Behe and Ken Miller had over it. Behe has since mentioned lactose metabolism in many speeches. At other times, to be sure, Behe has claimed that metabolic pathways aren't IC, but this seems to be an argument of convenience for him and he uses it only when confronted with evidence that this or that metabolic pathway has evolved.
quote: No, Gene appears to concede the evolution of IC metabolic pathways -- as shown by the PCP degradation example, which has three required enzymes. This is different than Behe, who says basically IC = can't evolve (or IC = wildly unlikely to evolve, a pointless distinction often tediously insisted on by IDists).
quote: Mike Gene says there's a huge difference between the PCP degradation pathway and the flagellum etc., but then the PCP degradation pathway has had (at most) only about 60 years to evolve, as PCP was introduced as an artificial pesticide only in 1939 IIRC. It probably took rather less time than that, given that really only a few mutations were required (the key mutation was simply regulation). The point that the pathway makes is that "multiple parts required" is no barrier *at all* to evolution. Numerous similar examples, e.g. atrazine degradation, experimental studies of the evolution of multipart metabolic pathways in the lab, etc., support the point. To back up: the main argument against IC is change-of-function, i.e. cooption. As you've been reading Mike Gene, you know that his response to this argument is (1) to concede that it works in certain cases but that (2) it is an appeal to chance and is therefore a very unlikely explanation. But he admits that the PCP degradation pathway, with 3 required parts, was assembled from enzymes with other original functions! (One of them is quite a radical switch, too) And if we look at evolution in general, we see that change-of-function is a ubiquitous event, not radically unlikely at all. Essentially every gene origin event is a cooption-of-function event. Your hands were not always functioning as tool-using hands, but in your ancestors were climbing hands, before that feet, and before that fins. Here is some of the documentation backing up the above:
Topic: Co-option/change of function, literature citations on its long-recognized importance in evolution The Origin of "Information" (new genes especially) via natural causes, Refuting a key ID claim (refs, webpages) quote: On the evolution of PCP degradation:
quote: quote: I've had a number of online debates with Mike Gene, so everything I say about what he thinks is simply my interpretation based on that experience. You are free to ask him yourself. Unfortunately I don't keep a database of Mike Gene quotes on tab. I am, however, sure he knows a lot -- in fact, he knows enough to know that (despite being tremendously complex and IC according to Behe) there is plenty of evidence and a thick stack of peer-reviewed literature indicating that the immune system did, in fact, originate via evolution. This, too, undermines Behe, Nelson, Dembski, et al. My opinion is that arguments for ID based on biological complexity are rather badly undermined once the evolution of horrendously complex things like the vertebrate immune system is conceded. Mike Gene thinks that the idea is still salvagable. He is written a lot on why but I for one still don't "get it". If you have better luck, please explain it to us... Thanks, nic [This message has been edited by Nic Tamzek, 12-01-2002]
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Nic Tamzek Inactive Member |
One more on atrazine degradation; this article is handily free online here:
Just a moment...
quote: nic [This message has been edited by Nic Tamzek, 12-01-2002]
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