Biological Principles Successfully Guide Students' Generative Mechanistic Reasoning.

How do undergraduates use biological principles to guide their reasoning when solving novel problems? Is it an effective strategy? To address these questions, we analyzed real-time discussions from small groups of students in an Introductory Organismal Biology course. We created a reasoning framework to characterize how students activated and linked their knowledge when constructing mechanistic explanations. We found that the principle of flux (flow rate ∝ gradient/resistance) served as a schema, a set of interconnected knowledge elements, that guided students' reasoning by focusing their attention on key components and their interactions. Students who used flux to guide their reasoning were more successful in constructing domain-plausible mechanistic explanations than students who did not use flux to guide their reasoning. However, students who used flux incorrectly, such as applying the wrong gradient for a given scenario, were less likely to generate domain-plausible answers. Our findings emphasize the importance of teaching disciplinary core principles, or core concepts, as schemas. Prioritizing core principles that function as predictive scientific models, providing explanatory power across contexts, can support students' generative reasoning. Still, students require foundational content knowledge, such as understanding gradients and resistances specific to each context, to effectively apply these principles.