After our disastrous chick lab — it turns out that getting fertilized chicken eggs shipped to remote Morris, Minnesota during a blizzard is a formula for generating dead embryos — the final developmental biology lab for the semester is an easy one. I lectured the students on structuralism and how there are more to cells then genes (there’s also cytoplasm and membranes and environment) earlier today. This afternnon I’ve given them recipes for soap bubble solution and told them to play. They’re supposedly making little model multicellular organisms by chaining soap bubbles together, and observing how the membranes follow rules of organization just like the ones we see in living tissue.

In case you’re wondering what the recipe is so you can do it too, here’s my bubble soap formula:

• 5ml Dawn dishwashing soap

• 100ml DI water

• 1ml glycerine

It gets better as it ages — there are perfumes and a small amount of alcohol solvent in the dishwashing liquid which evaporate off with time. The students are playing with concentrations, and if you’re making it up fresh and don’t want to wait until tomorrow, you can increase the concentrations of soap and glycerine.

The more glycerine you add, the more long-lasting the bubbles are…and unfortunately, the heavier they are. If you want bubbles that will waft gently on the breeze, you’ll want less glycerine. It’s a very forgiving recipe, just play.

I’ve also provided the students with a couple of books: the classic Soap Bubbles: Their Colors and Forces Which Mold Them by C.V. Boys, and The Science of Soap Films and Soap Bubbles by Cyril Isenberg. They’re more about math and physics, but they have some nice illustrations. These are projects you can do at home with cheap ingredients bought at the grocery store, so those of you with kids might try playing with it this summer. There are simple rules about the angles of intersection between bubbles — if you’re mathematically inclined, take pictures and use a protractor and see if you can work them out. There’s also some really cool stuff going on with colors, since the bubbles have a gradient of thickness from top to bottom and you get wonderful colors caused by refraction and reflection and phase shifts across the membrane.

OK, if you don’t have kids, you have my permission to play with soap bubbles, too. Tell everyone who looks at you funny that you’re doing Science!

Today was the last day I lecture at my developmental biology students. We have one more lab and one final class hour which will be all about assessment, but this was my last chance to pontificate at them…so I told them about all the things I didn’t teach them, and gave them a reading list for the summer. (I know, there’s no way they’re going to take these to the beach, but maybe when they move on in their careers they’ll remember that little reference in their notes and look it up.)

So here are the books I told them to go read.

We’ve been all up in the evo-devo house this semester, so I urged them to read the antidote, just to get some perspective. This is the great big book all the grown-up developmental biologists read and admire and regard as gloriously wrong in many ways, but still an important reminder that physical and chemical properties of whole cells and organisms matter — it’s not all genes. And of course that legendary book is On Growth and Form by D’Arcy Wentworth Thompson. I tell all my students that if ever they want to get serious about developmental biology, they must read Thompson.

For the more modern gang who like computers and math and logic puzzles, I point them at At Home in the Universe: The Search for the Laws of Self-Organization and Complexity and The Origins of Order: Self-Organization and Selection in Evolution by Stuart A. Kauffman. He’d really benefit from more time in a wet lab, but still, there’s some very provocative stuff in those books about how complexity can spontaneously arise. I also gave them a bit of an introduction to NK network theory.

There is always a philosopher or two in the class, so for them I suggest that they read The Ontogeny of Information: Developmental Systems and Evolution by Susan Oyama. Developmental Systems Theory suffers for its lack of applicability — it really is a little too abstract for most scientists — but I love it for its more holistic approach to development.

For the hardcore biologists, the ones who are ready to read a book where every page makes them think very hard, I suggest Developmental Plasticity and Evolution by Mary Jane West-Eberhard. It’s quite possibly the most brilliant book I’ve ever read, but it’s dense and challenging. Intentionally challenging: she really does question a lot of the dogma of evolutionary and developmental biology, and forces you to realize there are a lot of wide-open, intensely interesting questions out there.

And finally, I brought up a book I seriously think about making the class text every year, Ecological Developmental Biology by Scott F. Gilbert and David Epel. The course as it is now is a fairly traditional modern molecular genetics and development class, with a solid overlay of evolutionary biology. The Gilbert and Epel book integrates all that with ecology — and I firmly believe that the well-rounded biologist of the type a liberal arts university tries to generate ought to have a balanced conceptual understanding of ecology, development, and evolution.

That’s the short list. It’s too bad I don’t have total control of my students’ lives, or I’d have them studying ten or twenty books over the summer. Or they probably think it’s a good thing I don’t.

I’ve been terrible about updating everyone about my class the last few weeks — we’re coming up on the end of the semester, so I’ve been going a little bit mad. We’ve been focusing on vertebrate development lately, and right now we’ve got a few dozen fertilized chicken eggs sitting in an incubator and developing embryos. Maybe. It is always a real pain to get these things delivered to remote Morris, Minnesota — I delayed this part of the lab to the very end of the semester, hoping the sun would emerge and warm the hemisphere enough that when UPS took their sweet time getting them to me, they wouldn’t freeze in the back of the truck. As usual, though, next day delivery turned into two day delivery, and we haven’t seen Spring yet. So we’ll soon know whether they survived their harrowing journey through the frigid Northlands, and if they haven’t, I’ll have to throw up my hands and cry.

Or I could torture my students to ease my frustration. Yeah, that’s the ticket. So it’s exam day.

Developmental Biology Exam #3

This is a take-home exam. You are free and even encouraged to discuss these questions with your fellow students, but please write your answers independently — I want to hear your voice in your essays. Also note that you are UMM students, and so I have the highest expectations for the quality of your writing, and I will be grading you on grammar and spelling and clarity of expression as well as the content of your essays and your understanding of the concepts.

Answer two of the following three questions, 500-1000 words each. Do not retype the questions into your essay; if I can’t tell which one you’re answering from the story you’re telling, you’re doing it wrong. Include a word count in the top right corner of each of the two essays, and your name in the top left corner of each page. This assignment is due in class on Monday, and there will be a penalty for late submissions.

Question 1: One of Sarah Palin’s notorious gaffes was her dismissal of “fruit fly research” — she thought it was absurd that the government actually funded science on flies. How would you explain to a congressman that basic research is important? I’m going to put two constraints on your answer: 1) It has to be comprehensible to Michele Bachmann, and 2) don’t take the shortcut of promising that which you may not deliver. That is, no “maybe it will cure cancer!” claims, but focus instead on why we should appreciate deeper knowledge of biology.

Question 2: There is an interesting tension in evo devo: on the one hand, we like to talk about the universality of molecular mechanisms, but on the other hand, we’re also very interested in the differences, both in phenotype and genetics. This is an old debate in evolutionary theory, too, so it’s not unique to development, but how do you reconcile unity and diversity simultaneously?

Question 3: When I told you about axis specification in Drosophila, the story was relatively straightforward: maternal factors switch on a chain of zygotic genes that set up the pattern. When I told you about the same process in vertebrates, though, I didn’t give you the same level of detail—I gave you buckets of transcription factors and said they had various roles. Dig deeper. Pick ONE of these vertebrate dorsalizing factors out of the bucket and tell me more about it: noggin, chordin, frizbee, goosecoid, pintallavis.