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Mayra C. Vidal
Graduate Student
mayra.vidal@du.edu
Department of Biological Sciences
University of Denver
Animals on Treadmills: Critical Thinking and Public Perception of Science

This group-based, interrupted case study challenges students' perceptions of "useful" scientific research. We present student groups with the methods used in two scientific studies that have been heavily scrutinized in the popular media. Both research programs gained notoriety for their seemingly ridiculous methods that each included running animals on treadmills. Students are first asked to develop potential scientific questions and hypotheses that may have been addressed by the studies. Next, we share the real hypotheses tested, and ask students to interpret data presented in the resulting publications. Finally, students are led through a discussion that challenges their initial perceptions of the research, considers whether the science was presented in an unbiased manner by the media, and cultivates mindfulness about how critical thinking can change one's initial perceptions. We developed this case study for a lower-division biology undergraduate course in ecology. However, it can be adapted for introductory-biology or upper-division biology major courses, and/or undergraduate students majoring outside of the sciences.


Butterfly Hunt: The Role of Density Dependence in Batesian and Müllerian Mimicry

This case study uses an interactive activity to illustrate density dependence in ecology classes. We developed a "hunt" using paper butterflies with warning signals on the upper side of the wings and symbols that indicate if a butterfly is noxious underneath the wings. Butterflies are distributed in four different patches with varying densities of noxious and palatable butterflies, simulating Batesian or Müllerian mimicry. Students can catch as many butterflies they want for a period of time, but if they catch more than three noxious butterflies they are out of the game. After the activity, students calculate the survival rate of each type of butterfly in each patch and discuss the implications of density and warning signals according to their results. Students then answer questions and build graphs using the data from the activity and knowledge from the class and the discussion. With this case study, students will be able to understand negative and positive density dependence, as well as predation, learning, and convergent evolution, while recalling or being introduced to Batesian and Müllerian mimicry.


Shooting the Poop: More than Good Housekeeping?

This group-based case study is based on research by Dr. Martha Weiss using silver-spotted skipper caterpillars (Epargyreus clarus (Lepidoptera)). These insects perform the unusual behavior of flinging their frass (excrement) great distances away from their leaf shelters. This charismatic study system, besides being appealing to students, has the advantage of having several plausible alternative adaptive hypotheses to investigate. After viewing a brief PowerPoint presentation that introduces the perils of caterpillar life and a video demonstrating their unusual behavior, students brainstorm hypotheses and experiments to test them. Students then receive a set of datasheets and questions that guide them to an understanding of the actual experiments that Weiss conducted. The conclusion of the case provides an opportunity to discuss the difference between statistical and biological significance, a distinction often neglected. This case was developed for introductory-biology major undergraduate students, but can also be used in any undergraduate course involving the evolutionary concepts of adaptation and fitness.