Dissecting chicken wings in an introductory geology course to help students discover evidence-hiding in plain sight-of dinosaur-bird evolution

摘要

In an introductory geology course on vertebrate fossils, a new object-based classroom exercise was designed to enhance students' appreciation for evidence of evolution as a "tinkering" process, specifically in modern organisms with which everyone is familiar. During the dissection of a popular college late-night snack (barbeque-style chicken wings), students separated soft from hard skeletal tissue, undertook comparative anatomy of bird and human forelimbs, and discovered what is hidden in plain sight: the alula, a remnant claw that links birds to their evolutionary predecessors-the dinosaurs. A follow-up, anonymous questionnaire revealed that most students at the start of the dissection were not familiar with vertebrate anatomy or the skeletal structure of a bird wing. Upon completion of the dissection, most felt the exercise had helped improve their understanding of dinosaur-bird evolution, form and function, exaptations as tangible evidence of descent with modification, and analogous vs. homologous evolutionary features. The relatively small number of selfreported student learning outcomes precludes knowing how well the exercise can be adapted to large-enrollment courses. In such courses, however, the extra time involved in implementing the dissection exercise may pay off later during the term by serving as a foundation for discussions about other examples of evolution in the past and present.