Drs. Sharleen Flowers and Stephanie Gardner presented at JMBE Live! on September 29, 2023. Rachel Horak moderated the session. The title of the session was “Here Is the Biology, Now What is the Mechanism? Investigating Biology Undergraduates’ Mechanistic Reasoning within the Context of Biofilm Development.” Gardner spoke about the challenges of understanding complex biological systems. The Theory of Knowledge Integration was used as the theoretical framework. Gardner noted they identified fragment and transitional networks. Connected networks describe the connections between subsystems. The example was connecting DNA replication and the mechanisms. Flowers spoke about their dissertation work on biofilms. Despite their medical importance and inclusion in the ASM Curriculum Guidelines, there is a gap in the literature describing how biology students use mechanistic reasoning within systems to understand and reason with biofilms. The research question was stated as: what are the features of biology undergraduate students’ explanations in the context of biofilm development? Nine undergraduate biology students participated in semi-structured think-aloud interviews conducted in 2019. At the beginning of the interview there was discussion of the three subsystems: gene regulation, cell-cell communication, and phenotypic expression. Next, biofilms were introduced. After discussing the figure, the interviewer then asked the students to explain how a transition point occurs. For data analysis, the research team used deductive and inductive thematic coding (Creswell, 2013). They adapted the theory of Knowledge Integration (Clark & Linn, 2003) to guide characterization of the participants’ knowledge networks. Two researchers then discussed the agreement. The number of links between subsystems was used to categorize explanations. For example: no links, linear linkages to phenotypes, subsystems converge on phenotype, or interconnected phenotype. They then compared the normative model to the student models. They noted that several students did not include cell-cell communication. The researchers explored how students described the biofilm transition point. The team used four connection codes: mechanistic, specified causal, unspecified causal, and associative connection. Mechanistic connections accounted for 15% of the codes only. No student included all nine expected phenotypic and subsystem entities. Two-thirds of students (6/9) discussed all three phenotypes. Only two students out of the nine integrated both cell-cell communication and gene regulation into their explanations. The research team then investigated the level of organization and localization.The levels of organization cellular and macromolecular were observed in all nine students. However, not many molecular entities were described. Localization refers to where these processes occurred: most provided “unspecified” and few noted “inside the cell.” With this information, the research team developed a model of student knowledge integration within biofilms. The model spans fragmented (fewest amount of connections), transitional models (more connections and subsystems), and connected models (most specified and correct model). The values in terms of students were 4, 4, and 1 for each of these models. The research team concluded that many students in their sample may not possess an integrated perspective of biological systems: they noted isolated ideas with few connections and missing entities and subsystems. Flowers noted that gene regulation was a possible sticking point. The researchers theorized that “students’ mechanistic reasoning within the biofilm system may be limited by transfer of knowledge […] too far from no context to biofilm?” The instructional implication noted by Flowers suggest the importance of scaffolding. Flowers also suggested two models: MACH and MAtCH for scaffolding. The researchers thought that cueing prior knowledge can help. Horak emphasized how this was a example of DBER and qualitative research. Flowers explained that anyone in the biology major fit the eligibility criteria. Any class standing could participate in the interview. One student who did “better” in the interview may have recently taken cell biology. Gardner spoke about the “scope of inference” and how the learning experiences at other campuses would require more research. Flowers noted that in another study, instructors also did not describe mechanisms. Gardner noted that the literature supports more opportunities for reinforcement and repeated practice with feedback. Gardner also mentioned that a lot of the mechanistic reasoning literature is from K-12 environment. Flowers also spoke about the importance of prompting in semi-structured interviews.
