Education research demonstrates the effectiveness of active learning in increasing academic performance in both large lecture classes and small classes. Active learning (AL) engages students by encouraging application, discussion, and synthesis of material during class meetings. Here we share results of using specific AL interventions designed to help students develop a scientific understanding of global climate change and carbon cycling, difficult concepts for students because they require associating the impacts of sub-cellular processes with organismal and ecosystem functioning. Between fall 2008-spring 2010, three instructors at three different universities implemented AL strategies in both majors and non-majors ecology. A fourth instructor served as the lecture-only control. Validated and published diagnostic question clusters were used as pre- and post-assessments to assess knowledge and reasoning about global climate change and ecosystem carbon transformations (e.g., photosynthesis, decomposition, cellular respiration, and biosynthesis). The AL interventions included small group and whole class discussions of situations addressing both anthropogenic (burning of fossil fuels) and natural (ecosystem carbon cycling) contributors to global carbon cycling and accumulation of carbon dioxide in the atmosphere.  

Results/Conclusions

AL showed the strongest improvement over lecture for conceptual questions that directly aligned with the class activity. For example, 45% of the students in an AL class correctly answered a question about carbon transformations resulting from natural and anthropogenic processes compared to only 13% for the lecture-only class. AL had a less pronounced, yet still beneficial, effect on student improvement with less conceptual questions, such as interpreting seasonal changes in carbon dioxide levels. With solely lecture, 60% of students answered correctly compared to 68% with AL. With more complex phenomena that require making connections between multiple levels of organization, students struggled even with the use of specific AL techniques. For example, only 31% of the students in the AL classroom correctly associated decomposition as a source of atmospheric CO₂. With almost 70% of our students answering post-test questions incorrectly, we are not achieving our learning objectives for complex ecological phenomena. Thus, we need to critically examine our AL exercises and perhaps restructure the activities to integrate better or possibly use a single case study that guides students through the global carbon cycle.