Sunday, June 24, 2007

  Earwax and Evolution

The not-so-recent news article on the boy who had two spiders removed from his ear reminded me of a similar experience of my own.

In the Fall of 2001, while a sophomore in college, I developed a keen interest in paleontology, which I pursued with both coursework (including a class from the late Stephen Jay Gould) and a summer internship at the John Day Fossil Beds National Monument in Kimberly, OR. As an intern, the Park Service provided me with free lodging in a single-wide trailer at the Bureau of Land Management's Dayville Fire Guard Station. The trailer had seen better days--most of the window screens were filled with holes, large and small, and it was generally advised to put on insect repellent before going to bed. Combining this with the two weeks I spent at Philmont Scout Ranch that summer, I spent about 10 weeks in some form of open-air camping environment. It was great fun, and I enjoyed every minute of that summer.

Part of what I find so interesting about paleontology is the unique world-view that comes as a result of seeing exhausting examples of Darwin's "descent with modification" principle. Every feature we--or any other animal--have is a result of an ancestor, somewhere along the chain, having a slight gene mutation that ended up being more beneficial than not. This applies to everything: fingernails, five fingers, opposable thumbs, eyes, a four-chambered heart, blood cells, etc. It fascinates me to no end to learn the advantage of each trait and how it came about.

So, there I was, December 2002, in the doctor's office for my annual checkup, part of which is the eye-ear-nose-throat exam. As the doctor began to examine my ears, I asked what the purpose of earwax is. I never really understood it--it seemed to build up in my ears and require cleaning, but, for the life of me, I couldn't figure out how it benefited me (and it never occurred to me to look it up). He replied that there were two main thoughts as to the utility of earwax:
  1. Keep the skin in the ear canal moist so that it doesn't crack/dry out.
  2. Keep dust/particles/insects out of the ear
As I was thinking about the two potential uses of earwax, the doctor remarked that I had a buildup of earwax in my left ear that he would have to remove. I was sort of surprised, as I hadn't felt anything, nor had I noticed any hearing loss in my left ear. So, the doctor took two elongated metal instruments (sort of like mini-spatulas) and began poking and prodding the offending lump of earwax in my ear. When he pulled it out and set it on the counter, he commented that it looked like an insect.

I looked closer: it was a wasp, encased in earwax.

A wasp. With a stinger. From my ear. Encased in earwax.

Suddenly, the second purpose of earwax, which I had pretty much discounted, became the most important function in my mind. Sometime over the summer, I figured, a wasp crawled into my ear, died, and was encased in earwax. I was surprised that I didn't notice anything wrong--no hearing loss, no discomfort, nothing. It took a periodic medical checkup to reveal how close my ear had come to being turned into a hive.

I had heard and discounted the false statistic that the average person swallows eight spiders a year, but, now, it doesn't seem that off-base. What I am sure of is how amazing our natural world is and how fortuitous it is that we have evolved protections against things as bizarre as wasps flying into ear canals.

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posted by AJM  # 2:37 PM  
We missed you at IMPEESA this week. You could have had as many spiders, mosquitoes, or mice as you wanted in your ears! And then we could have created a song about it!!! Ms Miller
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