| 1 | <p>This clicker case addresses several concepts related to the evolutionary ecology of herbivore defenses. A survey of several different studies that investigated chemical defenses in <em>Thymus vulgaris</em> (thyme) gives students the opportunity to develop hypotheses, pose potential experiments, and interpret data to develop a better understanding of not only herbivore deterrence, but also how natural selection can involve different pressures selecting for different phenotypes. The case study incorporates group discussion, analysis of experimental design, and data evaluation as central activities. It can be taught in a single 50-minute class session, an economy that is achieved in part by using a "flipped" approach. Students prepare outside of class by watching several short videos (one of which was made by the author) that teach the basics of herbivore deterrence and abiotic and biotic forces in the environment that can influence plant adaptations. The case study was designed for use in a large introductory-level class, but would also be appropriate for smaller classes or upper-level evolution courses.</p> | 1 | <p>The original case addresses several concepts related to the evolutionary ecology of herbivore defenses. This adaptation features consideration of ecological pleiotropy in <em>Nicotiana </em>plants, which are pollinated by <em>Manduca sexta</em> moths that also lay their eggs on the plant's leaves, thereby challenging the plant with herbivory. Terpenes are differentially regulated in <em>Nicotiana </em>flowers and leaves based on environmental cues, and our adaptation invites students to consider how and why this happens. After reading a <em>phys.org News</em> article summarizing recent research into these phenomena and participating in guided discussion, students have the opportunity for further practice in developing hypotheses, posing potential experiments, and planning realistic data collection procedures. This adaptation incorporates sensory observations and plant chemotype predictions in thyme varieties, group discussion, informal presentations to the class, and analysis of experimental design as central activities. We taught the original case study with these adaptions in three 35-45 minute periods in an introductory majors course that meets 3x weekly for 2 hr. 20 min. (combined lecture/lab studio format).</p> |
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