Wednesday, November 15, 2006

Earthworms Are Easy

I have mostly vague memories of my years at Somers High School (Somers, CT), dating back into the late 1970s. But even so, certain vivid pictures do manage to break away from this time-induced blur. Many of those pictures, predictably, came from biology class. Mrs. Santaniello was our biology teacher, and she was without question one of the least squeamish persons I have ever met in my life. (As coincidence would have it, Mrs. Santaniello's husband would one day be my orthodontist when I needed to get braces. I have no fond memories of wearing braces, but my teeth still look pretty good, so I got that much out of them.) Mrs. Santaniello rarely spared us the gruesome details of biological living. I remember thinking to myself - male chauvinist that I was - "How can a woman be so casual about carving up wildlife?" Fortunately for us beginners, however, our first dissection subjects were probably one of the most boring, unsympathetic animals on earth: the common earthworm.

The common earthworm (or "night crawler", from the species Lumbricidae terrestris) has a very basic internal structure, with a teenie-weenie brain, a ventral nerve cord, and eight pairs of aortic arches (hearts). Earthworms are hermaphroditic, having both testes and ovaries for breeding (although they cannot self-reproduce). Lowly that he is, Nature didn't bother giving the earthworm a set of lungs or gills, and gases are instead exchanged via its own skin. [resource]

Earthworms are easy to dissect, which makes them ideal for novice anatomy students. Simply slice them along the middle of their bodies (length-wise), pin back their flesh, and wa-lah! - the interior of the earthworm is before you. No head to cut off, no arms or legs to sever, and no rib cage to saw through. Thinking back, I can't remember anyone ever protesting our classroom dissections (though I'm sure some individuals might have refused), so I imagine it wasn't the big controversial deal that it appears to be today.

Other than their academic utility (or for use as fish bait), earthworms rarely garner much interest from most folks. Humans have found heroism in dogs and dolphins, silliness in otters, notoriety in snakes and sharks, and nobility in eagles. Even the insect world has found celebrity with the legendary Jiminy Cricket. Alas, there are no such famed earthworms in our human history (unless you count "Squirmin' Herman"). One would certainly hope that when we do meet up with the aliens, they find a better use for us than the earthworm has found thus far.

Earthworms are also remarkably easy to draw, which made them a favorite of mine a few years back in my failed attempt at making some spare cash as a cartoonist.

(click images to enlarge)

After the earthworms, our biology class later moved on to the more popular frog dissections, which were a bit more complicated. Of course, it wouldn't be high school without somebody slicing off a few chunks of frogleg meat and stashing them in some poor unsuspecting kid's tuna fish sandwich in the cafeteria.

Ah, the memories.


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