Monday, October 03, 2005

Name That Tune

I know I promised to write about William Harris's talk a couple of weeks ago, and I am working on it -- I got about halfway through and could not muster another thought about creationism. Once I get motivated again, I'll try to dig through the waste and emptiness and finish it up. I hope to have my comments up within the next week or so.

In the meantime, here's a little game to keep you entertained. Let's play a little "Name That Tune"! This one is in the category of "The Conservative Nature of Natural Selection". In how many sentences can you name that tune (author and/or publication):

Sentence #1:
"Natural selection has been extremely effective in policing allelic mutations which arise in already existing gene loci."
Did anyone get it? It doesn't sound like a very controversial statement about what we refer to as purifying selection. Let�s move on to sentence #2:

"Because of natural selection, organisms have been able to adapt to changing environments, and by adaptive radiation many new species were created from a common ancestral form."

Well, it's definitely not a Young Earth Creationist (YEC); YECs don't believe in adaptive radiation. Some Intelligent Designers (IDers) also don't believe in adaptive radiation, but some do. What does sentence #3 hold for us:
"Yet, being an effective policeman, natural selection is extremely conservative by nature."
Oooh, anyone see where this is going? For more sacrilege against the god of natural selection, see sentence #4:
"Had evolution been entirely dependent on natural selection, from a bacterium only numerous forms of bacteria would have emerged."
Natural selection can't account for all of evolution!? All we would have is bacteria!? And "forms" sounds a lot like "kinds". What blasphemy! Ok, maybe it gets better in sentence #5:
"The creation of metazoans, vertebrates and finally mammals from unicellular organisms would have been quite impossible, for such big leaps in evolution required the creation of new gene loci with previous nonexistent functions."

Evolution would have been impossible . . . if it wasn't for this type of event that the author hints at. Some of my readers may see where this is going. I'll give you a clue: we're not talking about a mystical force creating new genes or biochemical pathways. For those of you who need one more line, here is sentence #6:

"Only the cistron which became redundant was able to escape from the relentless pressure of natural selection, and by escaping, it accumulated formerly forbidden mutations to emerge as a new gene locus."

Give up? No, it's not from some creationist tripe. This is actually from the Preface of a well respected book within evolutionary genetics: Susumu Ohno's Evolution by Gene Duplication published in 1970. Yes, even thirty five years ago evolutionary biologists did not need intelligent designers to tell them that natural selection is not the be all, end all of evolutionary forces. We've known it all along, and without gene duplication (via retrotransposition, segmental duplication, and whole genome duplication) evolution would have ceased with the simplest of all prokaryotes.

You see, it's easy to attack a caricature of evolutionary theory consisting of only random mutation and natural selection, but that's just a straw man. Understanding evolution to any extent requires one to examine more than just the pop culture concept of Darwin. Natural selection on allelic mutations cannot explain much beyond within population variation and speciation; to truly appreciate the amazing diversity of life on earth (and some within population variation and speciation) we must invoke genome rearrangements, neutral processes, and many other evolutionary forces . . . or we could just say "Goddidit!"

Lastly, it really bothers me that people justify the ID movement by arguing that it makes biologists consider other things besides natural selection when it really just wastes our time with silly arguments. You can make a pretty good career out of contributing to the knowledge of a field, but to go down as a legend you must lead research in a new direction. The fathers of evolutionary genetics (Dobzhansky, Wright, Fisher, Haldane, et al) did just that. So did Ohta Kimura with his neutral theory. We don't need anyone telling us to do good research and come up with new ideas. Now, you can argue that ID is just the newest in a long line of novel evolutionary concepts. Of course, you would be wrong if you did. See, what differentiates Behe, Dembski, and Wells from the real scientists is that the latter actually understood the field they were revolutionizing. Attacking the god of natural selection is a pitiful battle because no real evolutionary biologist worships at that altar.

Ohno, S. Evolution by Gene Duplication. Springer-Verlag, New York, NY.


At 9:42 PM, Anonymous Anonymous said...

Nice post. I admit, I didn't guess Ohno until I read the last clue. At first, Kimura was highest on my list. And I own the damn book! Another useful weapon against the ID claim that evolutionary biologists should "consider other explanations" is mentioning the contemporary debate between natural selection and demography.

Just one nitpicky detail... Though both Kimura and Ohta collaborated on the neutral theory, Kimura was more well known for it. Tomoko Ohta was more known for her contributions regarding the nearly neutral/slightly deleterious model.

At 3:30 PM, Blogger RPM said...

Oops, my bad with that one. Yeah, I meant Kimura, but I wrote Ohta (probably because it looks so much like Ohno).


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