TEACHING AND LEARNING ABOUT CLADOGRAMS IN GEOLOGY COURSES: INSIGHTS FROM PRIOR WORK IN BIOLOGY, A PILOT STUDY IN A PALEOBIOLOGY COURSE, AND COGNITIVE SCIENCE

A cladogram is a branching diagram commonly used to depict hypotheses of evolutionary relationships, and is a central representation of evolution in the fossil record. Recent research in the biological education community has identified expert-like skills and uncovered several common student misconceptions and other student learning difficulties associated with reading and interpreting cladograms. “Tree-thinking” skills are included as standards for high school science in many states, yet such skills remain challenging for college-level students after explicit instruction. I report here on the results of a pilot study in which we test the efficacy of a combined lecture-lab module for a paleobiology course in improving student understanding of cladograms. The goals of this study are to: 1) apply recent research and curricular ideas for teaching cladograms in biology courses to geology courses; 2) assess to what extent conceptual survey results from our students compare with results from published studies, and insights that gives us into curricular reform; 3) develop a cognitive science framing of cladograms that informs their use in professional science communication and teaching. Preliminary results suggest that misconceptions and student learning difficulties previously reported in biology education literature are present in paleobiology students’ thinking. A curricular intervention using an “invention-type” activity combined with additional activities focusing on student learning difficulties can be effective at improving student understanding. However, a significant portion of students still demonstrated previously identified common misconceptions after instruction, such as “tip proximity = close relationship” and “straight line equals no change”. Additionally, some students seemed to rely on prior knowledge of what they thought evolutionary relationships should be between common animal groups, rather than using trees to interpret relationships. A generally applicable finding from prior work, cognitive science, and this study suggests that “ladder”-style diagrams are significantly more difficult to interpret than “tree”-style diagrams, and thus the “tree”-style cladograms are recommended for use in both professional communication and teaching.