Friday, November 27, 2009

Why is the "black box" so complicated??

I received an e-mail question about a recent article I wrote with a graduate student. The question shows a common misunderstanding of evolution, and I thought it would be interesting, or at least potentially useful to more that one person, to post my response here.
Hi Dr. Oakley,

I am writing a research paper and came across your paper entitled, Opening the “Black Box”: The Genetic and Biochemical Basis of Eye Evolution. I was hoping you could give me your perspective on a question that is part of my research interest.

Since a simpler mechanisms for phototransduction would theoretically work, why would evolution favor a more complicated phototransduction cascade with intermediates such as transducin and PDE? I would greatly appreciate any insight you could provide me.

The implication in the e-mail is that evolution is a force that produces sleek perfection. Expensive solutions to problems should not arise by evolution (or at least they should not be maintained), especially if the complexity is unnecessary. This is a modernist view of biology, a view that can be found in 20th Century biological research, and a view that is also common today among students, and the general public outside the field of evolutionary biology. It is a view that results from an often unstated assumption natural selection is a supremely powerful force that leads to perfection.

From this Modernist, Bauhaus perspective, it is indeed perplexing to learn that opsin initiates a complex, baroque, Rube Golddberg-like cascade to turn light energy into a nervous impulse. This cascade includes reactions from opsin->transducin->PDE->CNG; each protein signaling in one way or another to another protein down the line - and this description is even VERY simplified compared to the actual complexity!

So the question is, why would evolution "favor this complicated phototransduction cascade", when all that seems to matter is that opsin signal directly to the CNG ion channel protein to cause the nervous impulse.

The most direct answer is that evolution is not an Intelligent Designer, rather it is a bricoleur, a tinkerer. Evolution acts upon what is available, and things that are useful are kept. In the case of the phototransduction cascade, evolution co-opted existing components: an existing GPCR cascade gained light sensitivity. We know this because the components of phototransduction pre-date opsin (e.g. here). Phototransduction was not invented from scratch, in the most efficient way possible. Instead, it was cobbled together using available parts.

This can be conceived as an example of a phylogenetic or historical constraint. In other words, history matters. All living things and all components of living things share a common history. Because of this, and because of the interdependence of components of living things, it is usually not easy to completely re-invent something. The number of shared genes in all animals (for example) clearly illustrates that history matters. Components are used and re-used, not invented anew.

This answers the proximate question, of why phototransduction is so complex. But doesn't address the question of why all GPCR cascades are so complex. I don't know the answer to this, but perhaps the complexity allows for flexibility. In fact, GPCR cascades are supremely flexible, and underlie signaling from outside to inside cells for many processes in animals, including vision and other senses, hormone signaling, metabolism, development, reproduction, etc, etc.

Interestingly, this question showed me yet another new perspective on the flawed argument for Intelligent Design. ID proponents suggest that when we see something outlandishly complex, then it must have been designed by an intelligent agent. However, as this question points out, extravagant complexity is not a sign of intelligence. Why use 50 components when 2 will suffice? Elegant simplicity is far more intelligent than excessive complexity. Again, evolutionary biology provides a logical and plausible explanation for the biological processes that we are coming to understand.

Saturday, November 21, 2009

Dispatch from the front lines of Ray Comfort's Krazee crusade

The "special" 150th anniversary edition of Origin of Species - the one with 59 pages of anti-scientific banana mush as an introduction - was handed out at UC-Santa Barbara on Thursday. Word on the street was that a number of campuses were hit on Wednesday, and by ~10:30am on Thursday, we at UCSB were starting to feel somehow let down, like we wouldn't get our chance to see the circus, and maybe just a little like a wallflower at the junior high dance.

Then the news hit. Graduate student Sabrina poked her head into my office around 11 and asked if I was ready. I was. Mostly I wanted my souvenir. Graduate student Chris Evelyn was already on the scene. Chris is an evolutionist with a strong competitive streak, and he was not about to let Ray Comfort's propaganda be distributed freely. Chris had found two people handing out the books near our library, and he contacted Sabrina, who let me know. I rattled off an e-mail to our Biology email list, and headed off to battle.

Aside from people paying to throw pies in the face of frat boys (fund raiser), demonstrations to save ESS (UCSB's exercise department is getting cut), flyers from "Jews for Jesus" (sounded interesting, but I didn't get one), and some other activity and demonstrations around the library (Free Palestine!), I saw no copies of the Origin, and no sign of Chris or Sabrina.

"We're over at the UCEN", Sabrina sent me a text. I walked 5 minutes over to the University Center. It was another fine Santa Barbara day, crystal clear blue skies, 70 degrees, and crisp shadows from the intense sunlight. The Comfort-ites, two of them, had run out of books. They had each carried a backpack-full to near the library, where Chris had found them. Now they were making plans to get more books. They had to park in Isla Vista, a 15-20 minute walk from the library. Chris followed them to their van - he didn't want a single book to be handed out without an NCSE flyer. Sabrina and I went back by the library to wait for the return.

By that time, my email had hit the biology department. About 10-15 other biologist found us and together we waited for the return of the banana editions. Independent of us, an Undergraduate Skeptics group called SURE was on the scene. They were prepared with flyers from Don't Diss Darwin and had written a counter argument to Comfort's banana-mush preface. Chris, still following the distributors, kept us updated by text messages. "They have hundreds of books in a van!"

Finally, they arrived, and I got my copy. I talked a bit to one of the distributors. "Jason" had a full red beard and wore a baseball cap. I learned he lives in Ojai, and he's 35 and unemployed. He had a calm demeanor, and he didn't know what he was getting into. He had recently joined a bible study group, and his friend "Mike" asked him to help pass out some books. He did not expect any sort of confrontation at all, and went out of his way to make clear that he didn't really know about what was in the book. He'd hand out a book and say things like "make sure you get a flyer and see the other side of the argument".

The other distributor, "Mike" was a older than Jason, maybe 60. He was a bit more evasive, and for a while seemed to want to get away from the skeptics and the biologists. I didn't get a chance to talk to Mike myself, but I learned that he was a veteran of military service. After a while, he too was telling people to get our flyers, to be fair. Poor Mike - most everyone I saw was a biologist just trying to get one of these laughable souvenirs. Poor Jason - he was just helping out a new friend, handing out some books.

We invited Jason and Mike to come to our screening of "Judgment Day: Intelligent Design on Trial". They declined. Their goal was to hand out all the books. Chris made sure flyers were present, and the Skeptics were troopers, too, sticking with the distributors through the evening; although several came to the screening.

After the screening, I got another text from Sabrina "Debating going on near the library". I already had plans to take my kids to the UCSB soccer game, first round of the NCAA tourney (we won, 1-0). Chris and Sabrina, and probably Nathan, were fighting the good fight though, and I think almost no books were handed out without a flyer or NCSE banana-bookmark, or both, as accompaniments.

A little activism was fun, and I was proud that evolutionism and rationalism had a much stronger presence than anti-science banana-mush. Although this sort of thing can be energizing, in the end, I mostly feel bad for Mike and Jason. This feeling was echoed by an email I got just now from Chris.

Chris thinks that, in the end, all this was just a cheap scam perpetrated by Ray Comfort. We found out that Mike put up money to buy these books. Comfort wrote a bunch of crap, tagged it to the beginning of Darwin's classic, published cheap copies, and then used his propaganda machine to get gullible buyers to spend their money.

I shouldn't be surprised. This to me is the lowest point of religion: the fact that (somehow) charismatic, yet underhanded people seem always to be able to lighten people's wallets in the name of religion. It's happened for centuries. Still, seeing it in action, and meeting the victims, makes me feel completely empty. I'm reminded of a time when I visited New York City and street con artists pulled cash right out of the hand of my friend. The rest of the trip was not the same. It seems to me that Ray Comfort is no better than one of these street con-artists. Perhaps it would've been more fun to be at UCLA, where Ray himself was, instead of witnessing his victims gradually realize they were caught in a scam.

Wednesday, November 4, 2009

10 Great advances in evolution-Nova Beta has a new format for their web-based information on Evolution. There is a lot of great information there. Here is an article by Carl Zimmer entitled "Ten Great Advances in Evolution", which draws upon similar material to his new textbook.