Conceptual system modeling for ecology and evolution instruction: Aligning assessments and evaluating practice
Evidence suggests that students learn science most effectively when engaged in the disciplinary practices used by science practitioners. As an operational framework, Vision & Change provides specific recommendations about the disciplinary practices and associated core concepts considered foundational for learning biology at the college level. We present an instructional approach that engages students in the construction of conceptual system models (CSM) as a strategy for regularly assessing students’ thinking in introductory biology. CSMs serve as representations of complex biological systems where interactions between system components explain mechanistic relationships, and the assemblage of interactions, as a whole, explains a biological phenomenon or system function. Constructing CSMs requires a suite of skills and cognitive processes that are consistent with our current understanding of systems thinking. For example, to build a CSM, students must identify relevant information across system scales, organize system components and relationships in a way that promotes understanding about the system’s function, and translate their mental representation into a form that can be communicated visually. As such, our application of CSMs in introductory biology explicitly targets 3 of the V&C disciplinary practices (science process, modeling, and communication) as well as the core concept of “systems”. We present evidence derived from multiple studies that illustrate how our use of CSMs has informed our understanding about students’ conceptual knowledge and skills related to biological systems thinking.
We observed that over time and in the context of a classroom structure that employs iterative bouts of practice and feedback, students are able to build significantly more parsimonious models to explain complex phenomena, such as evolution by natural selection. Importantly, gains are most pronounced for mid- and low-achieving students, suggesting CSMs may have particular utility closing achievement gaps for underprepared students. Student-constructed CSMs have also proven powerful in illuminating troublesome concepts and revealing gaps in student thinking. Data from multiple classrooms and institutions reveal pervasive challenges associated with explaining the origin and role of genetic variation in natural selection, ascribing appropriate biological processes to explain biogeochemical cycles, and understanding the nature of feedbacks and controls in system regulation. Collectively, our data suggest that CSMs are a viable strategy for instruction and assessment that aligns with existing frameworks for biology learning while promoting students’ systems thinking skills.