Thesis Defense, Kara Soule, 1/11/2013

The University of Maine
the Maine RiSE Center


MST Candidate
Kara Marie Soule
Thesis Advisor: Dr. Molly Schauffler
Submitted in Partial Fulfillment of the
Requirements for the Degree of
Master of Science (in Teaching)
May, 2013


        Scaffolding students’ understanding of how carbon is used to make energy available to
organisms, the biological processes involved, and the effects those processes have on systems at
many scales (e.g. cells, organisms, the biosphere), is important to helping them make informed
decisions as citizens — from personal health to public policy. This research investigates two
laboratory activities designed to enhance student understanding of carbon transformation in
plants. The undergraduate students participating in this study were enrolled in the Introductory
Biology course at the University of Maine in fall 2011. Student learning was compared among
three laboratory sections using two sets of pre-post surveys containing diagnostic question
clusters (DQC)s. Students in the comparison lab section (Class 1) followed the standard inquiry-based
laboratory procedures for the Cell Structure and Photosynthesis Labs. Students in the two
other lab sections did the standard activity plus one or both of two additional activities designed
to confront common misconceptions. Some students used a pH indicator, bromothymol blue
(BTB) for visual evidence that an Elodea plant produces CO2 through cellular respiration. A
third group of students did the BTB experiment and observed and reasoned about the feeding
behavior of a photosynthetic sea slug (Elysia chlorotica).

        Students who engaged in the trial lab activities had the greatest learning gains on pre-post
questions about the movement of carbon and energy through plants via photosynthesis,
biosynthesis and cellular respiration. Students who experimented with BTB and Elodea (Class 2
and Class 3) were also better than Class 1 at the end of the semester, in terms of applying their
understanding to reason about the loss of mass in plants, whether or not they observed the sea
slug. Results suggest that students’ understanding of carbon and energy flow through plants via
photosynthesis and cellular respiration can be enhanced through activities involving BTB with
Elodea and a photosynthetic sea slug.

Friday, January 11, 2013
10:00 am – 12:00 pm
Edward Bryand Global Sciences Center
Room 100