Trees and characters and common ancestors, oh my!

My teaching experience has taken a big step forward this month. I gave my first of two guest lectures to a large undergrad intro bio class (they clapped when I was done; I don't know what's wrong with them!), and am piloting a new module in lab this week. Both of these teaching endeavors are focused on the same topic: phylogenetics. Given that describing evolutionary relationships is one of my specialties, I was both excited and apprehensive to put these teaching materials together.

I've done outreach activities using phylogenetics before, and I've taught classes on computational phylogenetics. I was a teaching assistant in grad school for a semester-long class on plant systematics, which heavily featured phylogenetics. Striking the right balance for a single lecture and lab for an undergrad intro bio class was tricky. I skipped most of the tedious definitions and history of cladistics, as well as in-depth discussions of the attributes of various tree reconstruction methods. I did spent time talking about the practical applications of trees, and possible implementations of these techniques they might find interesting.

Why take that approach? Well, I operated under the assumption that most students wouldn't ever really build trees again, but they might perhaps need to interpret them. I also couched my discussion in the strength of comparative biology: what if we want to breed a better crop? What if we need to know how data about a gene in mouse transfers to a gene family in humans? What can a phylogeny tell us about how traits evolve? In that context, it's way more effective to spend time talking about interpreting phylogenies and deciding how much confidence you should have in them.

At the end of the day, phylogenetics is one of those areas which some students will just understand intuitively without much extra explanation necessary. Other students will struggle, ask questions, and it will take a long time to identify and then break through their misconceptions. The former students will get bored, think my lab is dumb and conclude it to be a waste of time. The latter students will get frustrated, think the lab is dumb and conclude it to be a waste of time.

OK, maybe I hope a few students will like it...and hopefully a few of the other teaching assistants learned something, too.