Intelligent Design

Hi originquestor.A couple of comments on your post. In the first place, Behe (not Dembski) is the originator of the idea of irreducible complexity inre flagella. Dembski's the guy who developed the concept of specified complexity and the explanatory filter that is supposed to identify true specified complexity from apparent specified complexity in nature (based on probability calculations). Obviously Behe's and Dembski's concepts are related, and Dembski is now spending an inordinate number of words trying to rescue IC from the dustbin. I think he's making a mistake, 'cause by linking the two ideas so closely, if one is falsified it automatically falsifies the other.As to Behe's flagella in particular, he's referring to eubacterial flagella. This is a key thing to remember, as the other two basic types have already had a great deal of research behind them - showing how they are not irreducible. One problem that Behe mentions (as you did in your post), is the existence of the so-called "o" rings (basal rings on the rotor). At first glance, since the only known homologues are Type III transport systems, and the fact that there are no known "primitive" versions (afaik), it looks like Behe might be on to something. However, by definition, if something is "irreducible" it means there is no possibility of variation - it either IS reducible, or it isn't. In the case of the basal rings, there are a number of eubacteria that have different configurations. For example, E. coli has four rings, Bacillus subtilis two rings, and Caulobacter crescentus five rings. As I have said before on this forum, it's fairly easy to imagine a scenario where a "primitive bacteria" might have one ring, and then you have a flagellum with two rings, then three, and so on through the well-known processes of gene duplication, fusion, etc. In other words, Behe is taking a fully-evolved "modern" organism with 4 billion years of evolution behind it, and saying (basically), "I don't know therefore god/designer didit". Looking at an organism post facto and declaring that it "couldn't" have evolved is quite different from looking at the organism and asking, "how?".

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Originally posted by Tranquility Base:
^ Nice try Quetzal - I noticed the one to two etc but it's the zero to one we are talking about!

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Weeell, not exactly. I pointed out that the rotor proteins are homologous to Type III transport systems (look up exb protein). I'm not saying that flagella evolved from these transport systems, just that the proteins are homologs. I'll certainly concede that we don't yet know the origin of the rotor system. The key word is "yet". Considering that all other forms of eukaryote and prokaryote motility systems (cilia, undulipodia, archaea flagella, etc) HAVE had quite reasonable evolutionary pathways shown for their development, I think it's pretty silly to insist that the eubacterial flagella is the only motility system that was "designed".Just for reference:Serganova I, Ksenzenko V, Serganov A, Meshcheryakova I, Pyatibratov M, Vakhrusheva O, Metlina A, Fedorov O., Sequencing of flagellin genes from Natrialba magadii provides new insight into evolutionary aspects of archaeal flagellins (J Bacteriol. 2002 Jan;184(1):318-22) for the archaea flagellaKaczanowski S, Jerzmanowski A., Evolutionary correlation between linker histones and microtubular structures (J Mol Evol. 2001 Jul;53(1):19-30) for eukaryote flagellaAlso, look up Margulis and others for a description of the possible ecto- and endosymbiosis origin of cilia. Especially look up Mixotricha paradoxa a colony bacteria comprised of five distinct species, two of which are used as motility/cilia for the others. I'm not as far out there as your hand-wave one liner would suggest.

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Originally posted by KingPenguin:
thats actually fairly plausable but again my major problem with evolution is what drives the organism to change and how did the organism come to be in the first place. anyway irreducably complex just means that its impossible to evolve to, but it can be evolved upon. come up with a just as plausable beginning for the organism and ill be happy.

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Hi KP. I'm not sure I understand your question. Seems to be three or four different questions buried in there.1. What drives an organism to change? Nothing "drives" an organism to change. Natural selection (among other things) operating on the variation that arises in a given population or aggregate of organisms can change the frequency of traits within the population - weeding out those traits that are less adapted or positively selecting those traits that provide some advantage. Individuals don't evolve, populations do (leaving aside bacterial gene swapping and single-generation speciation in plants for simplicity). As far as how eubacterial flagella were originally derived, I've admitted that's an open question. Adoption from a different function, elimination of functional redundancy, serial and parallel evolution are all possible routes by which these organelles could have developed. If in fact they are homologous to Type III transport systems, the latter is the most likely route. I guess I'll just wait for someone to figure it out for me. 2. How did the organism come to be in the first place? I'm not sure if you mean abiogenesis or descent with modification. In the case of the former, the jury is still out (although the results of research to date are pretty interesting). In the case of the latter, there is a ton of evidence from multiple disciplines that this has occurred. I'm pretty sure you've been given examples before. Maybe you could clarify what you're asking."anyway irreducably complex just means that its impossible to evolve to" Well, that's the question, ain't it? Neither Behe nor anyone else that I've read has established the impossibility beyond simply asserting it. It's quite possible that structures that are in fact irreducible today were evolved from the joining of two or more non-irreducibly complex structures of functionally indivisible components or cooption of existing structures. In both cases, the modern version we can see is, in fact, irreducible. However, through the scaffold effect or other methods the "irreducible" was in fact formed from quite reducible subcomponents. As I mentioned, this is Behe's major fallacy: he's looking at a structure that is irreducible NOW and asserting it was ALWAYS irreducible - that it essentially had to have been poofed into existence de novo. Since there are plenty of counterexamples in nature (except for the eubacterial flagella), I'd have to say his entire premise is false.

And TB, whenever you get around to answering my latest post on this thread, I'd appreciate it if you'd go back to this post and answer the question there. Thanks.