The third and fourth week of ecological developmental biology


I’d intended to make these reflections on the progress of my new course in ecological development a weekly feature on the blog, and then I failed to post an update last week. Bad professor, very bad. My excuse, though, is that I’m on a job search committee, we had three interviews in the last week, and they’ve all been kicking my butt and leaving me exhausted at the end of the day. That’s a duty that’s also a lot of work for us academics: there’s the gay social whirl all of a sudden, the scrutiny we have to give to each candidate, and sitting through job talks. The stress can be enormous, too — not for the candidates, although I’m sure they’re feeling a little anxiety, but for us. In the dream search, you bring in two candidates who suck and third that is gloriously qualified and a joy to spend time with, because then the decision-making is easy. In this case, we got three marvelous candidates and I want to hire them all, and we have to pick one. Just one. We’re going to make that painful decision on Saturday, so while all the work is done, the agonizing has only just begun.

And meanwhile, classes go on!

Last week was assessment time. I’m also teaching our genetics course, and they got an exam…an exam they did pretty well on, with an average of 79%. It could be that this cohort of students is just generally brilliant (but all of our students are brilliant), or it could be that some changes I’ve made in this class have been effective. I’ve been concentrating on laying a solid foundation: we’ve gone over basic Mendelian genetics, something I remind them over and over that they should have already been thoroughly exposed to and so this should just be review, and I also remind them over and over that later it’s going to get much harder and that we’re going to spend almost the entire semester talking about exceptions to this simplistic Mendelian stuff, and if they don’t fully grok the basics they’re going to be so screwed. We’ve also been working on a probability and statistics toolbox that they’ll be using repeatedly throughout the term.

I may have scared them into studying hard. Not only did they get a higher average score than past years, but the range tightened up considerably. I’m trying to build a strong foundation here, because as Al Franken explained to the nation in the DeVos hearings, we care more about growth than an arbitrary standard of proficiency. Give ’em the basics so the weaker students have something to build on rather than floundering and falling apart on the first day, and keep nudging them upwards at every step in the class.

My ecological development course also took a turn. The first two weeks, you may recall, consisted of the traditional Old Bearded Guy standing at the front of the room Old-Bearded-Guysplaining developmental biology to them — again, trying to put everyone on a firm footing in the fundamentals. The next step is to coax them into student-splain stuff to me. This has been harder than it should be, because this is an 8-fucking-am course, and I’m not my perkiest, and the students aren’t either. Next time I teach an interactive course, I must insist that it be offered sometime in the mid-day. Either that or demand IV bags from the ceiling filled with caffeinated beverages and start the morning going to each desk and jabbing everyone into alertness with a needle in a vein.

Instead of intravenous drugs, though, my approach to jump-starting their brains and making them comfortable speaking was to force them to do presentations last Tuesday. Short presentations; I gave them copies of Langman’s Medical Embryology, used a deck of cards to randomly assign each of them a week of human development, and had them give five-minute summaries of what was happening then: they had a few questions to guide them, like show what the embryo looked like, say something about critical events in their week, and discuss clinical correlates. It was straightforward and didn’t require intense thought, so it was simply a way to get them all to say a bit in class, as well as introducing a topic that we’ll return to in, for instance, a later discussion of teratogenesis.

Last Thursday, they had to talk again (I am such a cruel tyrant). They’d been assigned to read Lewontin’s Triple Helix, and this day was dedicated to a critical assessment of the text. I gave them a set of questions about the book, and then sat back and let them tell me the answers.

That actually went fairly well, I think. It still takes some time for them to warm up and get a conversation going, but they’re a smart bunch and we got some good discussion. It went well enough that we didn’t finish, so we extended the review to this past Tuesday. We identified a central theme of the book as construction: organisms are assemble themselves in an environmental context, and they are continually modifying their environment. These cycles of self-referential feedback mean that you simply cannot define an organism from nothing but its genome. They’re getting it!

This morning, I twisted the game around on them a little more. We’re digging into Gilbert’s Ecological Developmental Biology text with chapter 1, on normal plasticity, and this time I gave them the assignment ahead of time to write down three questions that chapter inspired in them. We spent most of our time bouncing questions and answers back and forth, which is always fun. I ended the session by listing some of the questions that got some vigorous responses, and putting them on the board. They were:

  • Temperature-dependent sex determination in reptiles: are there reptile intersexes? How often? We also got a suggestion that we should look more into behavioral sex determination in fish.

  • Inheritance of behavior differences: what causes differences in aggression in dog breeds? Is it genetically determined, how much and what genes are involved? (I asked where they fell on the continuum of biases about pit bulls, whether they where inherently vicious and needed to be put down, vs. a maligned breed that has a bad reputation because they are abused. I was surprised: 100% of the class came down in the not-intrinsically-evil camp. Dang liberals!)

  • Sneaker and dominant males: How do these differences within a sex in a single species arise? We discussed rhinocerous beetles and cephalopods.

  • Gravity. How dependent is development on this pervasive influence of gravity? We talked about some clear examples, like how the chicken body axis is dependent on rotation, and that led to speculation about human development and plasticity in microgravity. What happens to bodies in space? Can human fetuses grow normally in space?

  • Epigenetics…there were some good questions about that, but I deferred them all, telling them that we’re going to spend a whole week on epigenetics, so let’s take it off the table temporarily.

That was a good start. Then I divvied up the students — they volunteered for what subject most interested them — and sent them off to the library with an assignment, to find papers to address their question, and come back next Tuesday prepared to explain what they learned to the whole class.

Brains full. We stopped there. I’m looking forward to learning what they find next week.


  1. Jackson says

    The gravity question might be a good point to offer a little non-animal development. Gravitropism is important so when a plant seed germinates the roots go down and the shoots go up.

  2. anbheal says

    You sound like a terrific teacher, Dr. Myers. I remember with great fondness the handful of professors I had who got me to think in novel ways or who explained difficult arcana in ways I could grasp. Plus encourage analytical and scientific thinking.

    I was once hired to write test questions in biology for standardized high school exams. I was fired within a month. My sin? Questions that “demanded too much critical thinking”. For example, when they wanted a question about organic chemistry, I showed the main atmospheric components of several planets and moons, then asked, which would be the most likely environment where life might develop. Only one, a moon of Saturn, had any organic compounds (methane). The client’s critique was: “Far too analytical — you should have asked, “what does organic mean?”, and then let them choose between a) granola, b) sexual, c) hippies, d) carbon-based.”

    And this is why we have President Trump.

  3. Rich Woods says

    @anbheal #3:

    When I started writing this I was going to ask what the age of the students was for that exam, but I’m now thinking that I could only be disappointed by the answer.

  4. ChasCPeterson says

    Despite temperature sex determination, intersex turtles are almost unknown (here’s one).
    There is a pivotal temperature (PvT) that produces an equal sex ratio, but even then nearly all individuals are typically binary-sexable (but only via examination of the gonads at hatching). According to these guys:

    Functional hermaphroditism has not been reported in reptiles, though in some species, intersex gonads are occasionally observed in hatchlings incubated at the PvT; these typically resolve into testes over time (Pieau et al., 1998).

  5. says

    I hadn’t heard of any either, and suggested that there’d be a threshold effect, so intermediate responses would be unstable.