Print PageModels and visual representations of biological concepts are essential components of teaching and learning in college-level introductory biology. As biology progresses toward increasingly complex, multi-variate problems, instructors desire visualizations that can help simplify and communicate the complexities of biological systems. However, many standard representations present biological information in ways that may confuse or mislead novice learners. For example, despite the broadly held misconception that plants absorb carbon from the soil through their roots, many images of the carbon cycle depict the process of decomposition in the soil on or near plant roots. Other images of the global carbon cycle pose potential for confusion by omitting (e.g., plant respiration) or visually over-representing (e.g., industrial emissions of fossil fuel) certain pools or processes, presumably at the discretion of authors or illustrators wishing to emphasize particular aspects over others.
We applied a grounded theory approach to develop a rubric for quantifying and characterizing information depicted in typical representations of the global carbon cycle. We randomly selected 35 of the top 100 images returned from a Google Images search on the phrase “carbon cycle” and applied the rubric to quantify pools, processes, and accompanying labels included in each representation.
Results/Conclusions
Of the images analyzed, 87% included pools linked by process arrows that could be followed to create a cyclic path. However, over half (57%) of the models we examined included pools that were either dead-ends or dead-starts, and thus, were not fully integrated as part of a cycle. Of those, 50% represented fossil fuels as a non-integrated pool.
Atmosphere, soil, and water, appeared in 76%, 69%, and 49% of images, respectively. Plants were represented in a larger proportion of images (81%) than either animals (53%) or microorganisms (26%). Where arrows were used to indicate carbon movement from one pool to another, 56% of images included arrows that were not labeled and 86% used equivalent-sized arrows, regardless of flux rate or pool size. Photosynthesis was represented in 76% of images with an explicitly labeled process arrow, but respiration was much more variable, with some images indicating respiration associated with only specific biota (e.g., animals, microbes, plants) and not others.
Our project seeks to provide preliminary data about the way information is portrayed in carbon cycle representations. Research directed at how student use and interpret visual models will better inform biology instructors and illustrators about model elements most conducive to learning.
