A conversation about orthodontia today

It’s Friday, and that means that today I make all the students in my eco-devo class do all the work, while I sit back and observe. It’s too bad I can’t do this every day of the week, but I guess I have to do something now and then to earn my gigantic paycheck. Anyway, on Fridays I pick a paper relevant to the subject of the course, throw it to two student volunteers, and tell them to lead a discussion.

This week the paper is The Jaw Epidemic: Recognition, Origins, Cures, and Prevention by Sandra Kahn, Paul Ehrlich, Marcus Feldman, Robert Sapolsky, and Simon Wong. It’s about the fact that our jaws have been shrinking rapidly in some cultures, and speculating about why. The answer the paper gives is that it’s an epigenetic response to environmental factors, specifically diet but also respiratory phenomena. You might be able to see why this is of interest in an eco-devo class.

Some scholars, although they accept all or some of our narrative, still assert that part of the problem must be genetic or hereditary. They apparently do not realize that, because every attribute of all living organisms must to some degree be traceable to their DNA (or RNA), the statement is nonsensical. Nonetheless, some scientists continue to push partial blame for the epidemic toward genetic evolution while ignoring the etiology of jaw shrinkage and distortion. The success of some clinical techniques to normalize jaw growth in young children and abundant evidence that jaw shrinkage is a factor in both obstructive sleep apnea and the advancement of maxilla and mandible are key treatments, in addition to other surgical techniques. This further makes clear the largely environmental cause of the epidemic.

This confusion over etiology is a possible result of the genetic determinism that is characteristic of much of popular science. For instance, recent genome-wide association studies (GWAS) studies aimed at orofacial issues have been focused on possible genetic factors involved in the variation in the eruption of third molars (wisdom teeth). But they in no way suggest that selection and widespread genomic evolution explain the rarity of impacted third molars in hunter-gatherers compared with their common occurrence in settled or industrialized human populations). Similar problems occur when “racial” differences in the occurrence of jaw-related disease are discussed. For instance, Weinstock and colleagues (2014) found that African-American children were about 20% more susceptible to pediatric obstructive sleep apnea than children of other ethnic groups. But, unhappily, possible key environmental variables such as allergen concentrations at home or the length of nursing were ignored, as were different head shapes in different human groups that could make some more susceptible to the impacts of environmental change. In short, despite the great attention paid to a possible genetic evolutionary cause of the jaw epidemic, precious little evidence of genomic change being a significant factor has been uncovered.

I hope this sparks some good conversation. It’s a bit over-the-top to call it an “epidemic” of jaw shrinkage, but the hyperbole might trigger some arguments.

P.S. Their instructor is no gigachad. I grew up with a horribly crowded mouth with crooked teeth every which way that was treated crudely, by just yanking out a half dozen teeth to make room — we couldn’t afford braces or any finesse. Also, I had painfully impacted wisdom teeth that required an oral surgeon to take a hammer and chisel to my face.

Self-assessment time!

We’ve finished the third week of classes, I need to pause and think about my eco-devo class. You know, teachers do this: a class isn’t a set of railroad tracks taking us to a destination, and sometimes it’s worthwhile to reassess.

My goals with the course are clear. We’re studying a fairly new interdisciplinary science, we’ve got a good solid textbook, I’ve got a dozen smart students, let’s explore. I explicitly want to avoid turning it into a lecture course, where I just stand up and tell them what they need to know, so I constrained myself with some serious guardrails. I only lecture once a week, on Monday, and I don’t just tell them the answers, but give them a lot of questions that they have to answer as a group on Wednesday. I also give them a primary research paper to take apart on Friday.

Does it all work? Yes, mostly.

It wrecks my weekend, though. My Monday lectures have to cover some complex material while focusing the students on relevant questions. I can’t sink comfortably into a flurry of detail, as would be easy to do, I have to bring out the broader issues while simultaneously fleshing out examples with an appropriate amount of detail. This week we’re discussing developmental plasticity, for instance, and while the textbook sings a siren song of numerous examples that I could just recite, I have to provide context and ideas and questions that will motivate discussion on Wednesdays. I think this part of the class is going OK.

I think the students are doing the actual learning part of the course on Wednesdays. This is the day I do things like put them into groups, put stuff on the whiteboards, show that they are actually engaging with the material they’re being exposed to. It’s all on the students, and these are all smart students, so I’d really have to be bad at my job to screw this part up. I prime them with a few ideas that they get at the start of the week, and then let them go.

Fridays…I’ve got to work on my Friday class. I’ve got two problems here. One is that I appoint two students to lead the discussion of a research paper, which is fine, except that these danged ambitious students charge in to do all the work. I tell them to split it up, delegate, and put the rest of the class to work figuring out what is going on in the paper, but no, they try to do it all, and then the whole class sits quietly listening along. I may have to change how I organize those days.

The second problem is me. For instance, last week the theme was about the importance of integrating multiple perspectives to answer complex question, going beyond reductionism. And then I picked what I thought was a good paper that did exactly that, trying to identify the ecological factors behind snake evolution. It was too much. It started with a phylogenetic analysis, then applied a principal component analysis to skull morphology (uh-oh, bio students don’t get much experience with PCA here), added a bit of development/heterochrony work, and then tied all of those approaches together in a nice bit of synthesis. Cool, but too much for some undergrads to handle all at once. I am challenging them, at least, but I think I’d better take next week’s paper down a notch. While my goal was to make them read primary research, maybe I’ll have to ease them in with some review papers for a while, and give their brains a chance to release some pressure.

When I say it all mostly works, that’s entirely from my perspective. Maybe the students hate it, but because they’re all polite Midwestern people, they’re too nice to say it. I’m going to have to put together some kind of student evaluation form to hand out next week so I can find out if I’ve gone off the rails.

This is where I’m at on a Saturday morning at the end of the third week of classes, and now it’s time to immerse myself in background reading and lecture prep. One source I’m finding extremely useful for this course is Mary Jane West-Eberhard’s Developmental Plasticity and Evolution, which is a wonderfully rich source of ideas…but also would have undergraduate brains melting out their ears if I tried making this their textbook. One of my aspirations for this course is that they should be able to emerge from it at the end of the semester and be prepared to read West-Eberhard’s book without having a nervous breakdown.

That would be a fun graduate-level class to teach. Also about ten times more work than this one.

Oh no! It’s Monday!

It happened again. Monday rolled around. When will Science master the ability to predict these cataclysmic disasters? Surely there is some cause that we can treat. Vaccinations, maybe? Monday shelters, buried deep underground? Is there a pesticide that will selectively kill off all Mondays?

Once again, I’ve done it to myself: I set up all the material for my classes for the students on Monday, which effectively means my weekends are shot. This week we’re finishing up The Triple Helix with a conversation about the limitations of reductionism, Wednesday we discuss strategies for answering thorny research problems, and Friday we’re reading a paper about snake ecology, development, and evolution that takes a multidisciplinary approach. I’ve got it all queued up, almost as if I have a plan and know what I’m doing. I’m also tired, bleary-eyed, and I have a headache.

It is all my fault. The easy thing to have done would be to trundle through a series of lectures in which the students sit back with glazed eyes and absorb my wisdom, but instead I’m setting up frameworks and making the students do most of the work, at least two out of three classes. It turns out that’s far more work than just telling them what they need to know, so Mondays are going to be my days of pain.

The rest of the week, though, is cake. Mostly. Then this weekend I have to prep for next week, when we dive into the first chapter of our eco-devo textbook. Plasticity. Plasticity, plasticity, plasticity. That’ll keep us busy for a while.

Also, every day is grading day, and Tuesdays and Friday mornings are my spider days. I’ll recover tomorrow.

First round of Survivor: Morris cleared

Class went fairly well this afternoon, mainly because I’ve got a good, engaged bunch of students. The omens bode well for a good semester.

Me, lecturing

One catch: I haven’t spoken in over a month. Little bits of conversation, sure, but I haven’t used my voice in a sustained discussion in all that time, and I think it’s atrophied a bit. I made it through an hour, but at the end, it was all rough and gravelly and actually starting to hurt a bit. I’ve got to practice more.

I was also feeling a bit dehydrated. I’m going to start bringing a water bottle to work and take regular swigs throughout the day. Minnesota winters don’t help much, either: humidity bottoms out when it’s this cold, as my spiders will attest.

Evolution is the control of development by ecology

Today is my actual first day of classes. We had MLK Day off, and I have no classes on Tuesday, and today I get to meet the 12 students in my Ecological Developmental Biology course. It should be fun. I plan to present that famous aphorism by Van Valen, “Evolution is the control of development by ecology,” and then I’m done for the entire semester — once they’ve grasped that, there is nothing else left to teach, so we can just coast through February, March, April, and May.

OK, so maybe we should also think about the details. We’re going to spend the first two weeks diving into Lewontin’s The Triple Helix: Gene, Organism, and Environment. It’s short but clears the stage beautifully of any vestige of genetic determinism and primes us with an introduction to some fundamental concepts. Everyone ought to read it!

The rest of the semester we’ll work through Gilbert and Epel’s Ecological Developmental Biology. We’re going to talk about plasticity, epigenetics, symbiosis, developmental physiology, and the book has lots of material on teratogenesis, cancer, and aging (those are all developmental concerns, you know — we’re doing all the interesting and important stuff).

We’re also going to dig into the primary literature. This week, we’re reading a review by Sultan, “Development in context: the timely
emergence of eco-devo” to get everyone filled in with the background, but subsequent weeks will be mainly about primary research papers. There’s going to be a fair amount of reading in this class!

I’ve also made the radical decision to abolish all exams: about 60% of the grade is derived from just showing up, alert and ready to contribute. We’ll see how well that flies.

I’ll let you know. I’m thinking I’ll try to post a weekly wrap-up here, so that if I fail it’ll be visible.

Should I take attendance in my classes?

I’m working on my class policy for next semester. Last semester was rough — I had bent over backwards to provide maximum flexibility, with an online option and no mandatory attendance, and it was fairly typical to have only half, or less, of the class show up. I considered changing the policy mid-semester, but it was written into the syllabus, so I had to stick with it. There will be changes next term, I tell you what.

This little video illustrates my problem.

I really like the prisoner’s dilemma twist in the middle — if only one student shows up, they pass the course and everyone else fails. There was one day fall term where that could have been invoked.

To answer the question in the title: yes, I’m going to take attendance, and it’s going to count. My big class this spring is going to be heavily interactive, and I’ll need people to show up.

iNaturalist has been observing me

iNaturalist does this thing where they’ll give you a graphical summary of your contributions in the past year. Here’s mine.

See all the orange? That’s what they use to color-code arachnid observations. I might have a little bit of a bias there, and I have no idea how any birds and mammals crept in there, and I’m afraid plants don’t exist in my universe. Still, despite my narrow focus, I spotted 68 species this year. That’s not at all impressive. Can you name 68 species? Apparently, I can, and I’ve even photographed them.

I’ve been terrible at contributing identifications, that is, helping others by identifying what’s in their photos. I should aspire to do better at that next year.

Maybe I can strive to look at something other than spiders in the coming year, too, although that might be difficult, since they’re not as interesting.