The ecological flow of nutrients, water, and energy are generally represented as if they exist separately: a quick web image search will yield hundreds of depictions of the nitrogen, carbon, and water cycles in isolation. These images, which also dominate the visual component of our teaching about ecological cycling, don’t support student abstract thinking about how flows of matter and energy are inter-related. Can alternative depictions of ecological cycling aid students in integrating their understanding of these cycles? For the past few years, I have asked my undergraduate art, design, and architecture students to construct concept maps that consider how cycles of matter and flows of energy are inter-related in ecosystems. Students complete some background reading and discuss in class how carbon, nitrogen, water, and energy flow as a result of ecological processes and interactions. Small groups of students then create concept maps and share their maps with classmates via a learning management system. Each student-created map has inherent strengths and weaknesses in both its scientific content and how well it displays information. Instructor feedback and in-class discussion in response to each map can improve student understanding of how ecological flows are integrated through ecological interactions.
When students are asked to visually depict their understanding, the limits of their understanding become more apparent. Although each student-created map reveals different limitations, analyzing student maps from the past four years reveals some common trends. Maps tend to illustrate ecological interactions accurately, but rarely show the simultaneous movement of water, carbon, nitrogen, and energy through food webs. Some maps show cycling by depicting ‘complete circuits’, but it is common for maps to be missing one or more ecological interactions that complete a cycle. Occasionally students demonstrate an understanding of ecological inefficiency through their depiction of energy flows, but more frequently students only show energy entering systems via photosynthesis. Although the concept maps that I present were completed by a rather visually-oriented student body, the process of concept mapping is simple and intuitive enough to be mastered by students from all backgrounds and majors. Creating a concept map depicting a scientific phenomenon requires both a clear abstract understanding of that phenomenon and the ability to visually depict that understanding; these skills are of value to both majors and non-majors studying ecology.