Flagellum Evolution
| September 7, 2006 | Posted by Dave S. under Intelligent Design |
Nick Matzke at Panda’s Thumb, what evidence is there that the type III secretion system appeared in nature before the flagellum? If the flagellum coopted the ttss then the ttss must predate the flagellum. The ttss mediates elaborate interactions with plant and animal hosts of the bacteria. The flagellum on the other hand is for locomotion, not parasitic or pathogenic relationships with more complex cells. The flagellum is useful absent more complex organisms in the environment while the ttss is not. It seems to me quite likely that the flagellum appeared in nature before the ttss. Probably billions of years before as the following supports:
J Mol Microbiol Biotechnol. 2000 Apr;2(2):125-44.
Phylogenetic analyses of the constituents of Type III protein secretion systems.
Nguyen L, Paulsen IT, Tchieu J, Hueck CJ, Saier MH Jr.
Department of Biology, University of California at San Diego, La Jolla 92093-0116, USA.
Multicomponent Type III protein secretion systems transfer gram-negative bacterial virulence factors directly from the bacterial cytoplasm to the cytoplasm of a host eukaryotic cell in a process that may involve a single energy-coupled step. Extensive evidence supports the conclusion that the genetic apparatuses that encode these systems have been acquired independently by different gram-negative bacteria, presumably by lateral transfer. In this paper we conduct phylogenetic analyses of currently sequenced constituents of these systems and their homologues. The results reveal the relative relatedness of these systems and show that they evolved with little or no exchange of constituents between systems. This fact suggests that horizontal transmission of the genes encoding these systems always occurred as a unit without the formation of hybrid gene clusters. Moreover, homologous flagellar proteins show phylogenetic clustering that suggests that the flagellar systems and Type III protein secretory systems diverged from each other following very early duplication of a gene cluster sharing many (but not all) genes. Phylogenies of most or all of the flagellar proteins follow those of the source organisms with little or no lateral gene transfer suggesting that homologous flagellar proteins are true orthologues. We suggest that the flagellar apparatus was the evolutionary precursor of Type III protein secretion systems.
Update: I found this paper by Scott Minnich and Stephen Meyer to be extremely helpful in understanding the relationship of the TTSS and the flagellum.
71 Responses to Flagellum Evolution
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Ofro:
The argument that the flagella did not evolve is of course a classic argument from incredulity
Again it isn’t that it did not or could not “evolve”. That I have to keep stating that just demonstrates a lack of caring for reality.
Also without supporting data to say it could “evolve” via any method is faith, not science. And pointing to alleged homologs is not supporting data.
Ofro:
A big part of that argument is the claim that no subset of a structure could have been useful for any other purpose.
That is the anti-IDists’ claim. IDists make no such claim:
Irreducible Complexity is an Obstacle to Darwinism Even if Parts of a System have other Functions
From “No Free Lunch”:
IC- A system performing a given basic function is irreducibly complex if it includes a set of well-matched, mutually interacting, non-arbitrarily individuated parts such that each part in the set is indispensable to maintaining the system’s basic, and therefore original, function. The set of these indispensable parts is known as the irreducible core of the system.
Numerous and Diverse Parts If the irreducible core of an IC system consists of one or only a few parts, there may be no insuperable obstacle to the Darwinian mechanism explaining how that system arose in one fell swoop. But as the number of indispensable well-fitted, mutually interacting,, non-arbitrarily individuated parts increases in number & diversity, there is no possibility of the Darwinian mechanism achieving that system in one fell swoop.
Minimal Complexity and Function Given an IC system with numerous & diverse parts in its core, the Darwinian mechanism must produce it gradually. But if the system needs to operate at a certain minimal level of function before it can be of any use to the organism & if to achieve that level of function it requires a certain minimal level of complexity already possessed by the irreducible core, the Darwinian mechanism has no functional intermediates to exploit.
I suggest you take a step back and actually try to learn about ID from IDists. Then enter the discussion.
Joseph,
I don’t think you meant to address me with your reply (second time already). But I am honored to be confused with trrll. He is much more eloquent in his arguments than I. I hope he doesn’t mind.
Ofro:
I don’t think you meant to address me with your reply (second time already). But I am honored to be confused with trrll. He is much more eloquent in his arguments than I. I hope he doesn’t mind.
D’oh- My apologies to both
I am so poor I can’t even pay attention…
Tina,
Everything is natural. its just that the material aspect of reality which we currently inhabit makes up a tiny fraction of the whole reality,
As usual, you have explained very lucidly and logically what I express so poorly. I said almost this very thing on a thread yesterday. Your paragraph (post 56) explains why I keep insistig that there is no such thing as supernatural, while fully agreeing with Joseph that nature cannot cause itself.
Ofro:
One time I was shopping in a place where you pack your own groceries. Older daughter went to the car to fetch something just as I began to pack them with younger daughter. Younger daughter had some resentment, as she generally helped me greatly with projects while her sister always was busy. The car was visible, across the glass, but we could not see her and it was not in hearing range. Anyway, nobody spoke a word, because I stood there next to younger daughter. Suddenly, older sister burst in and answered her sister thus:
“I am not trying to get out of work! I had to go to the car!”
Both of their mouths dropped open, as they realized that she had responded to a thought, not a spoken word. And of course, younger sister was not making it up, as her jaw dropped as well, that she was thinking exactly that angry thought moments before.
You might try looking up Ervin Lazslo “Science and the Akashic Field.” And remember, I do not believe in supernatural.
avocationist and tinabrewer:
I agree with you, just about everybody had a similar experience that all of a sudden we thought of somebody or of something happening, good or bad, followed by just that happening. It has happened to me numerous times in the past few months that in just about the moment when I was going to dial my wife’s cellphone, she called me (and vice versa), or, just as I walked into my office, she called. That just begs the question; how come? Deep inside, we all would love to come to the conclusion that there was some physical/field/thought/spiritual/etc connection. But we have to ask ourselves seriously and honestly: how often did we have a similar thought, and nothing happened? This is very difficult for an untrained individual to answer accurately, and that is why I will not accuse anybody of lying about such an occurrence. Try it out on yourselves: whenever you come up with a random thought, make it a conscious effort to recognize it, “record it†so to speak, and see if anything actually happened as a consequence (mark that down again in your memory). I am confident that you will recognize soon that these random thoughts are not followed up by miraculous happenings, and the few mouth-dropping moments are chance events.
Now, that is different from situations like my phone calls, since we happen to call each other fairly frequently, especially when it is time to go home together. And, avocationist, I am quite sure that your situation was a similar one; which youngster would not think about the chance of getting out of a chore, or worse, about her sibling trying to that?
I may not even accuse a self-proclaimed psychic claiming to have a vision, although I admit I will be extremely suspicious. Just yesterday, on “The Infinity Mind†on Public Radio, a psychiatrist described a mentally disturbed person who became a pretty good “psychic†because he was able to put himself so well into the other person’s situation.
My private decision about a person’s honesty will eventually depend on how far-going and how often such claims are made. We all agree that there are plenty of charlatans who lie and cheat in order to dominate somebody or get their money.
As an aside, an amazing feature of our brain is that it can come up with all kinds of associations while it is churning in the background, and only some of these eventually surface as thoughts. Just as example for this surprising phenomenon: metabolic brain scanning studies have demonstrated that in anticipation of an action such as moving an arm, certain brain centers become active before the individual actually “knows†he/she made this decision.
So while I have no objections to two people having the romantic notion of connecting mysteriously; it can be a sign of a personal bond that holds them together. However, from a scientific standpoint I can give it no credence.
I agree, one should not call this supernatural. Or natural. It’s just not there.
Now I am really off-topic….
No, the IDist argument is a pure argument from incredulity: “I cannot think of a selectable pathway by which this can have evolved; therefore none exists.” This is a remarkably broad claimâ€â€to be able in one’s mind to imagine every conceivable pathway through the enormous multidimensional maze of possible mutational pathways, evaluate them for fitness, and conclude that no viable pathway exists. One bit of evidence, albeit somewhat weak evidence, that might be offered to support such an assertion would be if it could be shown that the components of the structure were so specifically adapted to this function that they could contribute to fitness in no other possible way. If this could be shown, it would certainly support the argument that the structure is IC. Lacking this, we are left with nothing at all other than the insistence of ID theorists that we trust in their ability to foresee every possible pathway.
ofro: if you are not already bored by the topic, see my comment #23 on the “selfish gene” thread which has moved to the next page.
avocationist: thank you for your kind words. I think you misjudge your own eloquence, though, which far exceeds mine. I have really enjoyed your exchanges with Carlos over on the other thread. Turtle down and all that!
Ofro,
Sorry, I cannot let you off so easily. The telephone thing of course I experience often enough, but for a person to walk in and answer something that she heard so clearly that she thought it had been spoken to her, and responded as such, only then to suddenly realize that what had just happened was impossible is quite something else. And at the same time, the younger daughter is shocked to find someone speak an exact answer to an exact thought that she had just had.
There had been no tension before my daughter went out to the car. As soon as she did, my younger daughter apparently began the train of thought as in, “how convenient.”
Another time, same younger daughter was feeling upset and wanted to talk with an old family friend on the other coast and strongly thought that she wished she could talk with him. A day or so later he called, and he said, “The other day I was in the shower getting ready to go somewhere, and I heard someone telling me to call, and it sounded like your voice.”
trrll:
No, the IDist argument is a pure argument from incredulity:
No the IDists argument is one from knowldge: “We know what intelligent agencies are capable of coupled with the knowledge of what nature, operating freely, is capable of.”
It is the anti-IDists who argue from ignorance guided by dogma: “We don’t know what mutations caused what changes and perhaps we never will but we know evolution did it.”
You can’t even tell us what mutations caused what changes or whether or not mutations can cause the changes required if evolutionism were indicative of reality. IOW evolutionism is dogma based on ignorance.
And again you display willful ignorance by stating the following:
I cannot think of a selectable pathway by which this can have evolved; therefore none exists.â€Â
Again ID is not anti-evolution. And “selectable” is very subjective- selectable by what? Ya see alleged IC structures could have evolved by an ID mechanism similar to the mechanism in “Evolving Inventions” SciAm Feb 2003. And you could falsify that statement, as oposed to your continued whining, by demonstrating RM&NS can account for such structures. But I can understand why you would rather whine…
The full abstract from the Matzke and Pollen article read:
I find that last sentence rather interesting. Without having read the full article (because I can’t get it), the indication here seems to be that all this paper really does is attempt to “speculate” (interesting word choice in itself) on how research into the issue of flagellar evolution might look. In other words, this paper itself isn’t presenting any actual lab results that would lead us closer to a detailed, testable model of how the flagellum evolved.
Even more interesting, though, (if one reads between the lines), is the implication here that no such experimental programs have existed to date, or if they have, they have not been successful. That would seem to fly in the face of all the claims that the evolution of the flagellum is a problem long since solved by biologists. Indeed, I have often seen long lists of research studies posted on blogs and around the net that supposedly demonstrate the detailed, testable model of flagellar evolution. Apparently, either Matzke and Pollen are unaware of all these research studies, or all those oft cited studies really don’t provide the model as claimed. If its the former, they are in good company as Behe himself was accused of not being aware of them when he wrote Darwin’s Black Box. If the latter, then several biologists and other participants in internet disussions are grossly misinformed.
Either way, though, the abstract seems to be a pretty strong indication that in the 10 years since Behe’s book was published, evolutionary biologists have still not solved the riddle of flagellar evolution in Darwinian terms, nor has a detailed, testable (and potentially falsifiable) model been developed. Further, it seems to also be the case that there really hasn’t been any detailed structure as to how a biologists would even go about conducting the experimental research, since this paper offers “speculations” as to how such research “might” go.
To me, this looks like a frank admission that no one has a clue how the flagellum evolved, which is exactly what Behe claimed in his book, and for which he has endured 10 years of mocking and excoriation from Darwinists. Matzke and Pollen are to be congratulated for being honest enough to admit that Behe was right after all.
Thought Provoker just doesn’t have the right spirit for our little community and won’t be with us any longer. Fare thee well, Thought Provoker.