There are benefits to both laboratory exercises and scientific modeling, and connecting the two may allow for deeper understanding and interest. Laboratory exercises provide students with opportunities to experience phenomena, but without scientific modeling, students may still lack understanding of the mechanisms at play. This article describes an example of how a traditional laboratory exercise on planarian regeneration is enhanced with a modeling activity on cell signaling.

Regeneration has long fascinated humanity, and its documentation has progressed from simple descriptive observations to the intense molecular and cellular investigations of today. The overarching goal of this work is to make the key methods and tools being used in modern regeneration and stem cell biology research accessible to docents and students in the classroom. We have designed a series of experimental activities with accompanying protocols using four inexpensive, commercially available planarian species indigenous to North America: Girardia sp ., Dugesia dorotocephala , Phagocata morgani , and Phagocata gracilis . These planarians are fast and robust regenerators, and can easily be maintained in the classroom. The activities presented here can be used to guide students through hypothesis-driven experiments, and range from simple manipulations aimed at high school students (e.g., planarian husbandry, feeding, and cutting experiments) to gene expression and protein function analyses suitable for college students. Regeneration time courses, the more complex whole worm in situ hybridizations, and RNA interference for gene knock-down experiments are described for each of the four species. Cumulatively, the suggested methods and experiments will facilitate the exploration of animal regeneration biology and promote curiosity-driven, hands-on application of the scientific method.