IMPLEMENTING TREE BUILDING INTO LARGE HISTORICAL GEOLOGY FLIPPED CLASSES

Flipped classes represent a chance to make a student, rather than an instructor, the primary driver of learning in the classroom. As this teaching technique generally involves interactive work, both instructor/student and student/student, flipped classes are often limited to small class sizes. We seek to demonstrate the feasibility of flipping large introductory classes (400 student Evolving Earth) as well the ability to teach complex subject matter like evolutionary tree thinking. After introducing cladograms and phylograms in a lecture setting, we then designed a flip activity asking students to construct their own cladograms. Students working in groups of five were given paper cutouts of imaginary creatures and asked to identify characters that could possibly be used to differentiate the organisms. Students were then given characteristics instructors previously identified as those differentiating organisms and asked to code each organism as “present” or “absent” for each character. We used a document camera to demonstrate the construction of nested circle diagrams using modern plants, with each circle uniting organisms with the same character states. Students were then asked to make their own nested circle diagrams using the paper organisms and the instructors’ predefined characteristics. We next demonstrated the construction of a cladogram from the plant nested circle diagram and asked students to construct their own cladograms with the paper organisms. Finally, the class came back together as a group to discuss the results for each step. This gave students an opportunity to not only observe other possible ways of organizing the characters, but also the process used to select which characters to start with. The step-by-step method of constructing a cladogram helped students to more intuitively understand how to read cladograms for any other group of real organisms at multiple taxonomic levels. By using imaginary creatures, students were more easily able to grasp the differences between a cladogram and a phylogram, as they were not confused by previous knowledge about the organisms’ evolutionary history.