Purdue University Graduate School
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Exploring Evidentiary Reasoning Instruction in Undergraduate Biology Labs

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posted on 2021-12-02, 16:18 authored by Chaonan LiuChaonan Liu
Recent trends toward engaging undergraduate biology students in scientific investigations have shifted focus toward helping students understand and use scientific evidence. Instructors must promote students’ evidentiary reasoning as they generate, use, and evaluate scientific evidence during the investigations. However, explicit guidance is needed for instructors to address students’ difficulties in understanding and using evidence when they are constructing claims and explanations in the scientific investigations. To unpack the complexity of evidentiary reasoning, my dissertation research was informed by the Conceptual Analysis of Disciplinary Evidence (CADE) framework, which I applied to the context of biology instructor professional development with three studies: two studies used the CADE framework as a lens to modify teaching of Hardy-Weinberg Equilibrium (HWE) and structural biology investigations and to provide lab instructors with support in guiding evidentiary reasoning for their students in an introductory biology course; a third study explored evidentiary reasoning practices according to interviewed members of the Faculty Developer Network for Undergraduate Biology Education (FDN-UBE).

With CADE as a framework, a novel HWE lab investigation was developed which highlighted evidentiary reasoning. Across three semesters, scaffolding questions to prompt reasoning with and about scientific evidence were changed in collaboration with lab instructors during professional development training with the CADE framework. Actual lab discussions were recorded to examine changes in the prompts implemented by one instructor. Findings showed that the instructor delved deeply into more facets of the evidence with the CADE framework. The lab instruction was intended to direct students to consider multiple aspects of evidentiary reasoning in a way that integrated their disciplinary knowledge with epistemic considerations about the nature, scope and quality of scientific evidence.

Structural biology investigations were modified in the second study in collaboration with graduate teaching assistants (GTAs) after a series of professional development trainings with the CADE framework. Lab discussions were recorded in four lab sections taught by two GTAs: one was a structural biologist and one was not. Each guided lab discussion in their two sections by leading evidentiary reasoning discussions in different ways: (a) with general evidence scaffolds (GES) and (b) with disciplinary evidence scaffolds (DES). Analysis of the lab discussions and interviews show that the GTAs’ instruction about evidentiary reasoning reflected their preferences and beliefs about the types of scaffolding questions they were using. With the GES, the instruction shifted from GTAs mainly introducing their own thoughts to more prompting of students to think and reason with evidence.

A third study employed the CADE framework as a lens to reveal evidentiary reasoning practices from interviews with members of Faculty Professional Developer Network for Undergraduate Biology Education (FDN-UBE). By coding segments of their interviews into CADE categories, I found that FDN-UBE members emphasized learning disciplinary knowledge, but with attention to further developing students’ epistemic reasoning and evidentiary reasoning and many emphasize the social dimensions of biological investigations.

In summary, findings from these three studies provide practical examples of instructors prompted students to use scientific evidence in terms of integrating epistemic considerations with disciplinary knowledge for evaluating development of evidentiary reasoning (or lack thereof) when students engage with biological investigations in undergraduate labs. The CADE is a systematic framework that supported a shift in professional practice toward more sophisticated epistemic reasoning in the teaching and learning of biology. The findings also provide implications for faulty professional development for supporting teaching about evidentiary reasoning in the future.


Exploring Biological Evidence: Helping Students Understand the Richness and Complexity of Evidentiary Constructs in Biology

Directorate for Education & Human Resources

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Degree Type

  • Doctor of Philosophy


  • Biological Sciences

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Nancy Pelaez

Additional Committee Member 2

Trevor R. Anderson

Additional Committee Member 3

Siddika S. Guzey

Additional Committee Member 4

Stephanie M. Gardner