Friday, April 9, 2010
Wisdom Teeth and Un-intelligent Design
A little while ago, I had my "wisdom" teeth pulled. It was my first time "going under" anesthesia, and, from what I can remember, I rather enjoyed that aspect of it... Except for the part when I woke up before the procedure was over, but then even that was a pretty good time... Apparently, the doctor and his assistants were marveling over how large one of my wisdom teeth was. So, when I awoke to hear shouts of "wow! that's a big one!" and "yeah, that is really huge", I replied "that's what she said." Which, perhaps because of the drugs, I thought was hilarious, though it didn't seem to go over so well with everyone else in the room. Probably because they weren't expecting me to take part in the conversation and were rushing around to put me back "under". In my haze, I must have also asked if I could have the tooth as they were somewhat adamant about giving it to me on the way out (pictured at right). Other than that, I also got to take home a nice bottle of vicodin and some antibiotics. After spending most of the day asleep, and a week or so recovering, I spent a little time thinking about what sort of blog fodder this whole tale might make. The first thing that comes to mind is how the whole practice of dentistry really is a testament to the validity of evolutionary theory and a prime example of UNintelligent design. You see, if our jaws were designed to hold all of our teeth, then wisdom teeth wouldn't get impacted and wouldn't have to be removed. Also, our teeth in general wouldn't be so crowded and likely to push each other crooked requiring so many people to get braces. And iff we had less, but perhaps wider teeth, or maybe wider gaps between our teeth, they would be easier to clean and less likely to get food stuck between them resulting in cavities that need fillings, and thus Ambrose Bierce would never have opined that dentists are "prestidigitators who, putting metal into your mouth, simultaneously remove it from your pockets." Of course, these sorts of flaws are exactly what evolution predicts, particularly in the case of wisdom teeth and the human lower jaw. As our primate ancestors evolved, two important things happened, our diet changed and our brains got bigger. Our early primate diet consisted of eating a lot of fibrous plant materials and gradually grew to include things like meat and fish and then ultimately to artificially selected and farmed (and eventually processed) foods that require less mashing. This made third molars ("wisdom teeth") non-essential for survival (and reproduction), and therefore changes in jaw shape could evolve without being selected against. The second change, our increasing brain size, caused our jaws to get smaller as a consequence of changes to the overall shape of the skull. Since there was a selective advantage to having bigger brains, and no serious disadvantage to smaller jaws, our skulls evolved in this way, with the end result being lots of trips to the dentist, othodontist, and oral surgeon.