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Examining and Supporting Mechanistic Explanations Across Chemistry and Biology Courses
Megan Shiroda1, Clare G-C Franovic2, Joelyn de Lima3,4
1Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, East Lansing, Michigan 48824.
CBE Life Sciences Education
|August 22, 2024
Summary
Students can explain complex science using causal mechanistic reasoning. Complete mechanistic explanations were lowest in introductory chemistry but improved with scale and in advanced courses like biochemistry.
Area of Science:
- Cross-disciplinary science education research
- Undergraduate chemistry and biology education
- Scientific reasoning and explanation
Background:
- Causal mechanistic reasoning aids in explaining complex phenomena by linking core scientific ideas.
- This reasoning involves identifying entities, properties, interactions, and constructing hierarchical explanations.
- Undergraduate science courses often emphasize core ideas separately, hindering integrated mechanistic understanding.
Purpose of the Study:
- To design scaffolded tasks promoting nested mechanistic explanations across molecular, macromolecular, and cellular scales.
- To investigate how mechanistic explanation construction varies across different undergraduate biology and chemistry courses.
- To examine the relationship between mechanistic explanation construction at different scales.
Main Methods:
- Developed scaffolded tasks requiring integrated biology and chemistry knowledge.
- Collected and analyzed student-generated mechanistic explanations from seven undergraduate courses.
- Assessed explanations for completeness (non-, partial, complete) at molecular, macromolecular, and cellular scales.
Main Results:
- Non-, partial, and complete mechanistic explanations were present across all courses and scales.
- Complete mechanistic explanation construction was lowest in introductory chemistry, similar in biology/organic chemistry, and highest in biochemistry.
- Smaller-scale mechanistic explanation construction correlated with larger-scale construction, but molecular scale use didn't fully predict cellular scale explanations.
Conclusions:
- Scaffolded tasks can support the development of hierarchical mechanistic explanations across disciplines.
- Student ability to construct complete mechanistic explanations varies significantly by course level and discipline.
- While smaller-scale reasoning supports larger-scale explanations, mastery across all scales requires targeted instruction.
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