I recently wrote up a brief summary of a TBL class period for another group. The topic was applying evolutionary thinking to medical questions. It was for an evolution class but could work for a variety of biology or medical classes, including medical anthropology. I used the Evo-ed site's slides for Lactase persistence and a freely available review article. See the description below. This was not my finest class period, but it worked pretty well and was fun!

Hope to hear from others using TBL in similar classes...

Heather

Team-Based Learning Module

Applying Evolutionary Methods to Medical Problems: The case of Lactose Intolerance

Heather Lerner’s[1] lesson plan using resources from the evo-ed site[2]

March 18, 2015

 

Learning Goals

·       Apply evolutionary thinking to a modern medical problem

o   Distinguish between proximate questions and evolutionary questions

o   Pose at least one proximate question 

o   Pose at least one evolutionary question of each type

§  Phylogenetic

§  Adaptive significance

 

Pre-class reading: Nesse, Randolph M., and Stephen C. Stearns. "The great opportunity: evolutionary applications to medicine and public health." Evolutionary Applications 1.1 (2008): 28-48. Freely available[3]

 

Pre-class reading guide: usually I have a list of questions for students to answer when reading a paper, but I haven’t yet developed a formal one for this. I asked them simply to focus on the tables because they provide a framework for organizing evolutionary methods/questions.

 

In class (50 minutes, 80 would be better, of course!)

A.    Introduce the lactose situation (this is basically a warm-up)

•       We give each Heather (our class has two Heathers, one is lactose-intolerant, and she was prepared ahead-of-time to answer questions about her reaction to dairy products) a large milk shake.

•       About 20 minutes later, one Heather is prancing around, full of energy

•       The other Heather is cramped up in the bathroom.

B.     Ask the class (or teams, depending on the size of your class): What happened?  (encourage students to get as deep into it as they can…why is she cramping, what is happening in her intestines? Why? What kinds of questions are you asking/answering here? Likely these are all proximate.)

C.     Each team, write up the two most important SPECIFIC proximate questions you need answered to understand what is happening (I skipped this part because I have a 50 minute class that talks a lot! And, this is an upper-level evolutionary biology class where I wanted to focus on evolutionary questions)

a.     Expect questions about the cellular mechanisms that underlie lactose tolerance versus intolerance

D.    Describe the cellular biology of lactase persistence (Evo-ed slides 5-17 or some subset depending on the amount of time available)

E.     Ask the teams to pose the two most important evolutionary questions they need to answer to better understand this situation (I try not to use problem or condition, so as not to alienate the lactose-intolerant students)

a.     Team 1 asked (primarily phylogenetic questions)

                                               i.     Which populations of humans have lactose tolerance (What are their cultures and diets like?) and

                                             ii.     What is the timeframe of evolution of lactose tolerance in these populations (compare timeframe of domestication of mammals, migration lines of humans and relatedness using microsatellites)

b.     Team 2 asked (primarily adaptive significance questions)

                                               i.     Are there any trade-offs for maintaining lactose-tolerance as adults?

1.     I asked them to brainstorm the pros of being able to digest lactose as adults in early humans (see slide at evo-ed “how did lactase persistence spread?”)

2.     Also asked them to brainstorm what the costs might be, then used the slides at evo-ed describing the “Molecular Genetics of Lactase Persistence”

                                             ii.     To what extent is lactose-tolerance linked to the evolution of the microbiome?

1.     This was exciting because they got to the idea of the gut bacteria being able to process lactose, which happens in one human population

c.     Ask the teams to label each question as phylogenetic or adaptive signifance

d.     Make sure to answer their questions using the slides from Evo-Ed (somewhat described above). Or, assign them some readings and have them turn in a few paragraphs (as individual homework) answering one of the questions they posed above.