Saturday, January 31, 2015

Teaching phylogenetics with DUPLO

I created a learning exercise for the MIT educational technique workshop. I wanted to chose a technique that activates the students and works as an introduction in an early class, and I picked the art and craft of making phylogenetic tree. I wanted to demystify what can be an abstract subject and give the students a tangible frame of reference.

My method of choice was DUPLO.

Intended learning objective: The student should be able to discuss basic principles for determining phylogenetic relationships based on quantifiable characters and be aware of the difference between core- and pan genome.

Method: The students are given photos of five DUPLO critters (or the critters themselves if you have enough pieces and they are not needed for a fire station). They work in groups with teacher available for questions to determine the phylogenetic relationship between five DUPLO critters. No additional information is given, and part of the exercise is for the students to discuss possible criteria for relatedness themselves. Hopefully they will realize that each column of blocks has two properties - color and frequency. After an hour the groups present their phylogenetic tree (for example by placing photos of the critters on a whiteboard with magnets). The results are discussed in full class.

Concepts to discuss:
  • Core genomes (colored blocks present in all critters)
  • Pan genomes (colored blocks present in only a subset of critters)
  • Choice of blocks to use for phylogenetics
  • Do order of blocks matter (chromosome rearrangement)
  • Construction of phylogenetic trees based on number of differences
  • Is there one correct tree? How do you know which tree is best?

    Putting together this exercise I realized how important it is to keep your intended learning objective in mind while choosing the technique. It is easy to complicate matters, and when I put together the snails I had to restrain myself from adding levels of complexity and thereby obscuring the point I wanted to make. I also learned that education technique does not have to be high tech to be highly effective.

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