The first week of Ecological Developmental biology


We’re off to a slow start in my brand new course, largely because I’m in the awkward phase of trying to catch everyone up on the basics before we plunge into the deeper waters, but also because the 8am scheduling is not good for inspiring interaction. Maybe it wasn’t the best decision to begin with a crash course in introductory concepts in developmental biology, because it’s encouraging the students to think that I’m going to do nothing but pour knowledge into their brains, but I’m at a loss to know how to get right into the primary literature without making sure they’re comfortable with the terminology and ideas of the discipline first.

The theme of the first week really was fundamental: polarity. How does a single-celled zygote figure out which end goes up? The students had to read a few chapters from the Gilbert developmental biology text (which is free online, at least in the 6th edition, which is good enough for a quick summary), specifically the chapter on anterior/posterior polarity (which is almost entirely about Drosophila, I added a fair number of examples from Ciona and echinoderms), and the chapter on the organizer in amphibians. That covered a good range, from an organism in which the orientation is pre-specified by maternal RNA (flies) to a case where it’s determined by an environmental interaction — the sperm entry point followed by a cortical rotation reaction (frogs). I also added a bit about mammals, where the decision by the blastula cells to form inner cell mass vs. extra-embryonic membranes is basically a chance event, biased by location in the cluster of early cells.

In all of the examples, though, the key point is that the decisions are not determined exclusively genetically, whatever that would mean, but are contingent on interactions between genes and cytoplasm, which also has structure and pattern, and that that structure may also be influenced by the external environment.

It was fun and familiar to me, but again I’m concerned that when I do most of the work, I’m encouraging passivity in the students. That role is continuing this week, when I give them the stories of neural tube and limb development, as examples of later organ systems that rely on complex interactions. The third week, though, I completely turn the tables on them: they’ve got some reading assignments for that week, and have to do short presentations in class. I’m just going to sit back and ask questions, and hope I don’t get bleary-eyed silence in response.

In my notes for what to do next time I teach this course:

  • Lobby for a better course time. 8am is too damn early for young men and women, even if it is just fine for us oldsters who don’t sleep as much and get up early anyway.

  • This section is a prime candidate for a flipped classroom approach — I could make some short videos ahead of time that they need to watch in their homes, with an accompanying set of questions that they’ll have to discuss in class. The problem there is that in-class responsiveness is one of their weaknesses right now.

  • Later in the course we’ll be trying some different pedagogical approaches: watch for what works best with this group, and maybe revise our crash course section to use that.


  1. marcoli says

    Very interesting. Keep us posted. I keep thinking of ‘suggestions’ of stuff you can do re getting interactions going, but I am sure you will do well. The first run thru the course has to be a trial run, subject to improvements and revisions later.

  2. marcoli says

    While I am here: I seriously don’t know how you find the perfect Far Side cartoon for different occasions. I would spend hours!

  3. multitool says

    How big is your class?

    My in-class reponsiveness was always low when I was acutely conscious my questions were holding up 30 other people.

    Classes felt a lot more accessible when the instructor broke us up into groups.

  4. jrkrideau says

    8am is too damn early for young men and women

    My first year at university was the first year classes started at 8:30. Not great but it certainly beat 8am. And in grade school and high school classes started at 09:00.

  5. cartomancer says

    Pffft, soft modern students – in the Middle Ages lectures started at dawn. Which could be as early as 4.30am on some days.

  6. blf says

    In the Middle Ages there was no convenient lighting, so you essentially had to work / study to the Sun’s rhythm.

  7. emergence says

    This is probably going to sound stupid, but is it possible for developmental abnormalities to screw up body axis polarity and result in an animal developing an ass on either end of its body? For example, could you tweak the development of a fruit fly larva so it grows a second abdomen where its head should be?

  8. says

    Ha, yes. I actually talked about experiments like that: make the gene bicoid defective in the mother (it’s a maternal effect gene), and you get flies with two butts. That die, obviously.

    You can also disrupt polarity in flies and echinoderms and get ‘vegetalized’ embryos — all they make is endoderm. Or add redundant polarity information and make animals with two heads.

    BWAHAHAHAHA, he laughed maniacally.

  9. emergence says

    I’m not up to developmental biology yet, but it sounds like it’s going to be fun when I do. This semester I’m going to be taking cell biology, deep sea biology, and quantitative methods for biology.

    Also, does anyone here have any advice on how to get hired as a lab assistant? I need some work experience if I’m going to get into this field.

  10. birgerjohansson says

    Going off on a tangent again, Re embryonic development, New Scientist had an article about tissue development as affected by electric currents. Among other things they had a photo of a frog with an eye at the butt after having embryonic development disturbed by electricity….
    If it had been another publication I would have assumed the article was bogus.

    (Also,, if I can grow extra organs all over, will that count as a superpower ?)

  11. Owlmirror says

    Comments by “zadesoh” look like olde-style manual spamming (or testing for spamability; that is, if the comments are not removed, this thread may be marked somewhere to be revisited by actual spammers)

  12. Owlmirror says

    Re embryonic development, New Scientist had an article about tissue development as affected by electric currents.

    I was hoping that PZ would comment on this as well. There’s one guy who wants to use electricity to regrow amputated limbs and heal spinal injuries in humans, based on work on amphibians. Sounds great at first, but then I wondered, why aren’t more biologists excited about this?

    Hm. I think I had read a different article about Michael Levin‘s work.