Hands-on Simulation of Frog Development and Experimental Embryology Engages Students and Promotes Learning

Categories: GSI Online LibraryTeaching Effectiveness Award Essays

By Danielle Spitzer, Molecular and Cell Biology

Teaching Effectiveness Award Essay, 2022

Problem: MCB 141 (Developmental Biology) is an upper-division lecture course that covers fundamental concepts of animal embryonic development. The students learn about foundational experiments in the field which involve precise manipulations to animal embryos in three-dimensional space. They are expected to apply the process of science by designing experiments, interpreting results, and drawing appropriate conclusions from data—skills which have been highlighted as a national priority for undergraduate biology education1—and yet, the course does not have a lab section where they can conduct experiments to authentically practice these vital skills.

Strategy: In Spring 2020, I developed a hands-on simulation of events in the early development of frogs, beginning with fertilization of the egg until the establishment of dorsal-ventral polarity (the distinction of the back and belly sides of a body). Students used modeling clay to construct a frog egg and simulate the physical events that follow, up through the second cell division. Using this model, the students also recreated classical “cut-and-paste” embryological experiments. They made predictions about experimental outcomes and used the model to explain results they had learned about in class. The evidence-based rationales for this activity were: 1) students in classes that implement active learning are more likely to achieve desired learning outcomes,2 especially students from marginalized groups,3 and 2) students learn best by engaging through multiple modalities that are suited to the material, regardless of preferred “learning styles.”4

Assessment: When I piloted this activity in 2020, my students received it enthusiastically, as evidenced by their eager participation in class and favorable course evaluations: one third of evaluations specifically referenced the activity as enjoyable or particularly useful. Encouraged by this anecdotal evidence, I chose to refine the activity and collect assessment data (IRB approved; CPHS #2021-11-14787) from future classes to better evaluate its efficacy. In the second iteration (Spring 2022), I partnered with the current GSIs of the course to administer the activity alongside an ungraded pre-assessment and an in-class worksheet to evaluate mastery of the lesson objectives. In the pre-assessment, only 47% of students could correctly identify the relationship between the site of fertilization and the site of the future “dorsal organizer,” compared to 72% on the activity worksheet. This represents a substantial gain in students’ understanding of how the processes of fertilization and axis induction are related in frog development, which was a central goal of the lesson. I also administered a Likert-style survey question to assess students’ self-reported perceptions of the effectiveness of the activity. Regarding the statement, “This activity increased my understanding of the material taught in class,” 87% of students either agreed or strongly agreed, 13% felt neutral, and none disagreed. I also solicited feedback and suggestions from students, which helped to improve the activity even more. For example, I changed the format from self-paced to synchronous at the suggestion of students in the first of four discussion sections, which subsequently increased the rate of activity and worksheet completion within the allotted class time from 42% to 100%.

Sources: 1) AAAS. Vision and Change: A Call to Action. (2010). 2) Freeman, S, et al. Active learning increases student performance in science, engineering, and mathematics. PNAS (2014). 3) Theobald, EJ, et al. Active learning narrows achievement gaps for underrepresented students in undergraduate science, technology, engineering, and math. PNAS (2020). 4) Pashler, H, et al. Learning styles: Concepts and evidence. Psychol Sci Public Interest (2008).