As we approach the 150th anniversary of the publication of On the Origin of Species by Means of Natural Selection, I can't help but notice the shoddy treatment natural selection receives in many of the college courses I have attended. Everyone is in agreement that understanding natural selection is important, so much so that it often gets its own lecture, but apparently it is not important enough to have professors memorize relevant examples of it.
I have seen it happen over and over again. The major points of evolution by natural selection are outlined (usually between 4 and 8 concepts, with the latter number being far too many) and the scientific revolution that Charles Darwin instigated explained. (This is rarely done well, but at least there is an appreciation for history.) Then examples of natural selection are given, but they are never anything Darwin included in On the Origin of Species or even more recently-discovered examples.
Instead the teacher picks some trait out of the air (usually canine teeth in lions, which says something about the way we think of natural selection as "nature, red in tooth and claw"). Some scenario is muddled through in which increased canine length is adaptive and therefore is selected for. Other times the professor recognizes that the hypothetical scenario isn't very realistic but runs with it anyway, and more often than not it seems to confuse more than enlighten. This is rarely connected to how major changes can occur over long periods of time, and the fossil record is never brought up.
Darwin spent a lot of time combing for evidence to support his evolutionary theory, but it would appear that many think that natural selection is so self-explanatory that real-world examples of it are not necessary. I do not want to hear imaginative ramblings; if we're talking about a real, observable process, then we should be talking about documented cases which illustrate the point. I would like to think that 150 years after On the Origin of Species was published we've been able to find some good examples of natural selection. There are plenty, of course, but you'd never know it from some of the lectures I have sat in on.
It is important for students to understand evolution by natural selection as theory, but that lesson should be backed up by evidence. Why some of my professors have failed to do so is beyond me. (I have taken a class taught by a professor who had dug deep to illustrate theories covered in class, and it is by far the best course I have ever taken in college. His course is the exception, however.) Does it have to do with preparation time? Do we think that the idea of natural selection is so obvious that it doesn't require us to offer up evidence of it in action? Whatever the reason, I do not think that students are served well by imaginative "just so" stories made up on the spot. And to think I'm paying $6,000+ a semester for this...
[As an aside, the campus was swarming with elderly white men handing out copies of the New Testament this morning. Not the entire Bible, just the New Testament. I must have run into at least six of them as I walked between bus stops, each lurching towards me, zombie-like, with the thin green books in their hands. I informed them I already had one, thanks all the same, but they eyed me suspiciously. I guess the very fact that I am a college student puts me in danger of damnation. I don't particularly mind if they want to hand out half of a bible to people who want it, but don't hassle me when I'm just trying to get to class on time.]
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As best I recall, the texts we used in introductory courses, and in general education courses, all had fairly modern, specific examples of directional, stabilizing, and disruptive selection. I used some other examples out of the literature. Wish I had kept my lecture notes.
It's interesting...my BIO 100 course was taught by this awesome young post-doc - who, unfortunately, was forced to go through a bit of the textbook cardboard just so as not to confuse some of the "less bright" people in the class. However, we spent more time in our labs learning about how important drift is and how it works on populations than we did learning about natural selection.
Its often a problem encountered with biologists teaching portions of a class on evolution. The problem is is that the sheer majority of evolutionary biologists (at least at Montana State) are all molecular folks. Now I have no problem with molecular folks, but they have no (zero, zip, nada) understanding of anatomy or morphology, and there is in addition to this sort of a general superiority complex of molecular workers over morphologists.
Not only did I have the problem you mentioned (e.g. shoddy treatment, or neglect per se, of the original morphological evidence used to identify evolution), but I recently took a course titled evolution, taught by two molecular biologists. They never talked about morphological evolution, save twice: a rhino's horn as hypothetical examples of different types of selection), and the vestigial pelvic girdle of a baleen whale, and remarking "they're still there... ya, thats evolution" (meanwhile, they could have forgone that entirely and used a few images of the incredible early whale fossil record).
The rest of the time that morphology was even mentioned was the professor literally saying "don't use morphology... it is subjective, and unreliable, and will get you nowhere." They went so far as to put that last point ON the goddamn take-home points list that they handed out to everyone. ARGGH!
Hey, Boesse - were you around that day back in September when those elderly white men were passing out New Testaments? I swear they had every crosswalk onto campus covered, some with 2, one on the left, one on the right, so you ended up seeing many students walking center aisle down the pathways... Annoying. I think for next semester, in honor of Darwin 2009, we should get mini-On the Origin of Species' and hand them out when they do it in the spring. Stand nearby and offer one to any person who accepts a New Testament. Just a thought for some evolution (reason, really) advocacy.
I had a geology professor who gave two examples of "evolutionary success" that I remember now close to 20 years later: if the two biggest, strongest, and most appealing creatures (I forget what animal he used as the example) are fighting over who is going to mate with the woman, and the scrawny, geeky creatures makes it with the woman, than he is the successful one while the traits of the other two will not be passed on (too bad this doesn't seem to work on Presidents).
The second was stating the number of offspring a couple needs to have to be successful is three, two is essentially a tie (creating a future generation that equals the number of people in the current generation), and one or less is a failure. As we hear the pitter-patter of cat paws running around our house, I am often proud to point out that I am an evolutionary failure.
Point being, it only takes a few good examples to make a lasting impression (and, as it worked for me, harboring on a successful exploit of a geek is probably a good path to take in a science class, no offense intended). To put it in perspective, often times the folks handing out their little green books will know its contents inside out; it seems that anybody attempting to stand behind their education, knowledge, and convictions should approach the job in a similar fashion.