The World's Stupidest Biochem Major

From the Wall Street Journal:

AMES, Iowa -- With a magician's flourish, Thomas Ingebritsen pulled six mousetraps from a shopping bag and handed them out to students in his "God and Science" seminar. At his instruction, they removed one component -- either the spring, hammer or holding bar -- from each mousetrap. They then tested the traps, which all failed to snap.

"Is the mousetrap irreducibly complex?" the Iowa State University molecular biologist asked the class.

"Yes, definitely," said Jason Mueller, a junior biochemistry major wearing a cross around his neck.

That's the answer Mr. Ingebritsen was looking for. He was using the mousetrap to support the antievolution doctrine known as intelligent design. Like a mousetrap, the associate professor suggested, living cells are "irreducibly complex" -- they can't fulfill their functions without all of their parts. Hence, they could not have evolved bit by bit through natural selection but must have been devised by a creator.

On a certain level, I find this utterly demoralizing: An adult college student of the sciences calling a moustrap irreducibly complex, such that he makes the absurd conclusion that the moustrap proves that a designer invented the universe - simply because he has a damn cross around his neck. Since Blogger kicks people off for violent speech, I'll keep my verbal response to this appalling miscarraige of reason quiet. Actually, the mousetrap could be simplified by bending the holding arm slightly and removing the latch. It is important, however, to clarify the nature of irreducible complexity, and what, if anything, we can deduce from it.

A system's state of irreducible complexity is not evidence of design, it is evidence of irreducible complexity. If a system stops functioning when you take Behe's tweezer to it and remove a single part, that simply means that that part was necessary. Even if you remove every component one at a time and find them all to be necessary, that is not evidence of design - it only illustrates one of two things: 1) that the pieces are interdependant, and you have not yet explored the effects of removing combinations of parts, or 2) that the system has reached a state of elegance and efficiency where it has shed its unnecessary parts. In both conclusions, it is the result that one expects from a process of iterative evolution. I am still dumbfounded as to how any of this is lost on the IDers. Actually, I'm not - it's lost on them because recognition such simple logic would prevent the introduction of the supernatural into scientific inquiry.

Dear readers, please read my previous post for catharsis, and this final quote from an otherwise bleak article:

Ms. West and other honors students will have a chance to hear the opposing viewpoint next semester. Counter-programming against Mr. Ingebritsen, three faculty members are preparing a seminar titled: "The Nature of Science: Why the Overwhelming Consensus of Science is that Intelligent Design is not Good Science."

I just don't feel the moral vigor to lambaste the idiot biochem major and his idiot teacher right now, so I'll reprint talkorigins.org's stock answer to their wrongheaded, predetermined conclusion: (link on sidebar)

Response:

1. Irreducible complexity can evolve. It is defined as a system that loses its function if any one part is removed, so it only indicates that the system did not evolve by the addition of single parts with no change in function. That still leaves several evolutionary mechanisms:
   
   
   • deletion of parts
     
   • addition of multiple parts; for example, duplication of much or all of the system (Pennisi 2001)
     
   • change of function
     
   • addition of a second function to a part (Aharoni et al. 2004)
     
   • gradual modification of parts
     
   All of these mechanisms have been observed in genetic mutations. In particular, deletions and gene duplications are fairly common (Dujon et al. 2004; Hooper and Berg 2003; Lynch and Conery 2000), and together they make irreducible complexity not only possible but expected. In fact, it was predicted by Nobel-prize-winning geneticist Hermann Muller almost a century ago (Muller 1918, 463-464). Muller referred to it as interlocking complexity (Muller 1939).
   
   Evolutionary origins of some irreducibly complex systems have been described in some detail. For example, the evolution of the Krebs citric acid cycle has been well studied; irreducibility is no obstacle to its formation (Meléndez-Hevia et al. 1996).
   
   
2. Even if irreducible complexity did prohibit Darwinian evolution, the conclusion of design does not follow. Other processes might have produced it. Irreducible complexity is an example of a failed argument from incredulity.
   
   
3. Irreducible complexity is poorly defined. It is defined in terms of parts, but it is far from obvious what a "part" is. Logically, the parts should be individual atoms, because they are the level of organization that does not get subdivided further in biochemistry, and they are the smallest level that biochemists consider in their analysis. Behe, however, considered sets of molecules to be individual parts, and he gave no indication of how he made his determinations.
   
   
4. Systems that have been considered irreducibly complex might not be. For example:
   
   
   
   • The mousetrap that Behe used as an example of irreducible complexity can be simplified by bending the holding arm slightly and removing the latch.
     
   • The bacterial flagellum is not irreducibly complex because it can lose many parts and still function, either as a simpler flagellum or a secretion system. Many proteins of the eukaryotic flagellum (also called a cilium or undulipodium) are known to be dispensable, because functional swimming flagella that lack these proteins are known to exist.
     
   • In spite of the complexity of Behe's protein transport example, there are other proteins for which no transport is necessary (see Ussery 1999 for references).
     
   • The immune system example that Behe includes is not irreducibly complex because the antibodies that mark invading cells for destruction might themselves hinder the function of those cells, allowing the system to function (albeit not as well) without the destroyer molecules of the complement system.
     

Links:

TalkOrigins Archive. n.d. Irreducible complexity and Michael Behe. http://www.talkorigins.org/faqs/behe.html

References:

1. Aharoni, A., L. Gaidukov, O. Khersonsky, S. McQ. Gould, C. Roodveldt and D. S. Tawfik. 2004. The 'evolvability' of promiscuous protein functions. Nature Genetics [Epub Nov. 28 ahead of print]
   
2. Dujon, B. et al. 2004. Genome evolution in yeasts. Nature 430: 35-44.
   
3. Hooper, S. D. and O. G. Berg. 2003. On the nature of gene innovation: Duplication patterns in microbial genomes. Molecular Biololgy and Evolution 20(6): 945-954.
   
4. Lynch, M. and J. S. Conery. 2000. The evolutionary fate and consequences of duplicate genes. Science 290: 1151-1155. See also Pennisi, E., 2000. Twinned genes live life in the fast lane. Science 290: 1065-1066.
   
5. Meléndez-Hevia, Enrique, Thomas G. Waddell and Marta Cascante. 1996. The puzzle of the Krebs citric acid cycle: Assembling the pieces of chemically feasible reactions, and opportunism in the design of metabolic pathways during evolution. Journal of Molecular Evolution 43(3): 293-303.
   
6. Muller, Hermann J. 1918. Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors. Genetics 3: 422-499. http://www.genetics.org/content/vol3/issue5/index.shtml
   
7. Muller, H. J. 1939. Reversibility in evolution considered from the standpoint of genetics. Biological Reviews of the Cambridge Philosophical Society 14: 261-280.
   
8. Pennisi, Elizabeth. 2001. Genome duplications: The stuff of evolution? Science 294: 2458-2460.
   
9. Ussery, David. 1999. A biochemist's response to "The biochemical challenge to evolution". Bios 70: 40-45. http://www.cbs.dtu.dk/staff/dave/Behe.html