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Whitley R. Lehto
PhD Candidate
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.

Life Tables, Darwin’s Finches, and the Dynamics of Small Island Populations 

This case study uses Darwin’s finches to teach students about life tables. Life tables are tables of statistics that relate to life expectancy and reproductive output for a population of organisms. Students are asked to tabulate traditional life table values like those obtained by evolutionary biologists Peter and Rosemary Grant, who study the dynamics of finch populations in the Galapagos Islands. Students next compare the survival of two different finch species as well as groups of the same species tracked at different time points. They then interpret and integrate information in multiple forms (numerical, graphical, and written) to address ecological and evolutionary problems. For instance, students produce their own survivorship curve from calculated life table values and, together with graphical data on annual rainfall, speculate on the relationship between rainfall and finch survival. Students also calculate reproductive rates and generation times of the finches and integrate the concepts of effective population size and genetic drift to discuss the dynamics of small populations. The case works well with any class size and is appropriate for majors in biology or ecology courses.