Missed connections: Exploring features of undergraduate biology students' knowledge networks relating gene regulation, cell-cell communication, and phenotypic expression.

Explaining biological phenomena requires understanding how different processes function and describing interactions between components at various levels of organization over time and space in biological systems. This is a desired competency yet is a complicated and often challenging task for undergraduate biology students. Therefore, we need a better understanding of their integrated knowledge regarding important biological concepts. Informed by the theory of knowledge integration and mechanistic reasoning, in this qualitative case study, we elicited and characterized knowledge networks of nine undergraduate biology students. We investigated students' conceptions of and the various ways they connect three fundamental subsystems in biology: 1) gene regulation, 2) cell-cell communication, and 3) phenotypic expression. We found that only half of the conceptual questions regarding the three subsystems were answered correctly by the majority of students. Knowledge networks tended to be linear and unidirectional, with little variation in the types of relationships displayed. Students did not spontaneously express mechanistic connections, mainly described undefined, cellular, and macromolecular levels of organization, and mainly discussed unspecified and intracellular localizations. These results emphasize the need to support students' understanding of fundamental concepts, and promoting knowledge integration in the classroom could assist students' ability to understand biological systems.

Here Is the Biology, Now What is the Mechanism? Investigating Biology Undergraduates' Mechanistic Reasoning within the Context of Biofilm Development.

Understanding molecular processes and coordinating the various activities across levels of organization in biological systems is a complicated task, yet many curricular guidelines indicate that undergraduate students should master it. Employing mechanistic reasoning can facilitate describing and investigating biological phenomena. Biofilms are an important system in microbiology and biology education. However, few empirical studies have been conducted on student learning of biofilms or how students utilize mechanistic reasoning related to systems thinking to explain biofilm formation. Using mechanistic reasoning and the theory of knowledge integration as conceptual and analytical frameworks, we examined the features of 9 undergraduate biology students' mechanistic models of a specific transition point in biofilm development. From these data, we constructed a model of knowledge integration in the context of biofilms, which categorizes students' knowledge based on features of their descriptions (e.g., entities, correct connections, and the nature of connections). We found that 4 of 9 students produced a fragmented model, 4 of 9 students produced a transitional model, and 1 student produced a connected model. Overall, students often did not discuss cell-cell communication mechanics in their mechanistic models and rarely included the role of gene regulation. Most connections were considered nonnormative and lacked important entities, leading to an abundance of unspecified causal connections. We recommend increasing instructional support of mechanistic reasoning within systems (e.g., identifying entities across levels of organization and their relevant activities) and creating opportunities for students to grapple with their understanding of various biological concepts and to explore how processes interact and connect in a complex system.