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The first page of the presentation includes photos of 12 animals. I print this page, cut up the photos, and give a set of photos to each group of students. Working in groups of 2 or 3, the students spend ~10 minutes arranging the photos to depict the evolutionary relationships among the animals. This exercise is followed by 4 clicker questions about relationships that students commonly misconstrue due to convergence or shared primitive features. I use the clicker questions to initiate class discussion of group results. Then we discuss the evidence (anatomy, biochemistry) for current thinking about these relationships. Once we have established a consensus, students are asked to place pictures of a subset of the animals at the tips of the branches on a pre-designed cladogram. The activity gives me insight into students' preconceptions regarding vertebrate phylogeny, encourages students to identify their own misconceptions, promotes peer instruction and highlights problems associated with determining relationships based on shared primitive features. Placing the animals on a pre-designed cladogram allows students to translate their hypothesis about relationships into a visual diagram, an exercise that I hope will help students to extract the phylogenetic hypotheses depicted on cladograms in papers and textbooks. Once we have established a consensus cladogram, students must go one step further and add evidence (synapomorphies) to their cladograms. Students spend ~ 10 minutes brainstorming with their group to place synapormorphies at each node of the diagram. An example is provided for whales and hippos, groups for which the evidence of shared ancestry is difficult to recognize based on the anatomy of living specimens. After adding synapomorphies to their diagrams, students will work together as a class, contributing shared derived features to a group cladogram. If time permits, it would also be possible to complete the exercise with a gallery walk, where each group posts a copy of their cladogram + synapomorphies on the wall for other groups to examine and edit.
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