I feel like I can do a pretty good job lecturing on most topics at a level that will hold the attention of nonmajors, but two exceptions are cell organelles and biomes. Don’t get me wrong — I love teaching how cells work, and I do emphasize organelle interactions in class. But reciting a list of organelles and their functions is not my idea of exciting, so I tell the students they need to learn that information on their own from the textbook.
Once upon a time, I lectured on the biomes, but nothing sucks the life out of ecology like a bulleted list of the climate, plants, and animals of each biome. (Yes, I included photos with my lists, but still … it was pretty dull.) Many years ago, I delivered the honest truth to students, and it went something like this: “I want you to know about the different biomes, but not enough to lecture on it in class. Go learn what’s in the lecture PowerPoint I posted on D2L.” Then I would pick out a Planet Earth DVD and let David Attenborough showcase the beauty and drama of just one biome. David Attenborough makes everything amazing.
But last fall, I received a windfall. I was out of town for a conference late in the semester, and my friend Mark Walvoord handled the biomes class. Mark is really good at finding ways to turn lectures into high-quality activities, and he took on the biomes challenge. I liked his idea so much that I used it again this semester, with great success.
Mark divided the 60-70 students into nine groups and assigned each one a biome: deserts, grasslands, taiga, tundra, tropical rainforests, deciduous forests, freshwater lakes/ponds, freshwater streams, and the ocean. Each group then whipped out an array of smart phones and laptops and worked at a frenzied pace for 15-20 minutes to answer the following questions:
- What is the biome’s location and climate?
- What abiotic forces have acted on organisms in the biome?
- What adaptations do organisms have that “fit” those abiotic forces?
- How do the organisms in your biome (biotic factors) interact?
- What adaptations do organisms have that are the result of biotic pressures?
- Propose an ecosystem-level research project you could do in your biome. Include the question, hypothesis, and methods.
As the end of the class period approached, each group reported its findings to the rest of the class. I especially liked hearing which adaptations the groups found noteworthy; students seem to really like connecting the features of plants and animals to specific selective forces, both biotic and abiotic. For example, the group studying deserts connected water scarcity to plants with hairs that shade their leaves and to thorns that deter herbivores seeking water. It’s not rocket science, but it is a good opportunity for students to explicitly connect an organism’s phenotype with its ecological context.
But my favorite part of the activity is the research projects the groups proposed. If you set nonmajors free to use their imaginations without imposing any constraints, some fun — if impractical — ideas emerge. One group proposed to measure how the deep ocean ecosystem would change if they installed lights on the ocean floor. (I still find myself thinking about what would happen!) Another group learned that the long bill of a toucan allows it to reach fruit on branches that are too weak to support the bird’s weight. Somehow they came up with the idea to put owls in rainforests and track the birds for many generations to see if their beaks would grow to toucan-style proportions.
After the class was over, I still posted my same old PowerPoint file on D2L, to make sure everyone had the same baseline knowledge about each biome. As I did so, it dawned on me that I hadn’t given much thought to which biomes we explored in class. I wish I had added temperate coniferous forests, since students might have encountered that biome during their travels within the U.S. The tropical savanna and polar ice are also absent, which is a shame since both of those biomes house some really charismatic organisms. The problem is that the more student groups you create, the longer it takes to deliver the reports.
It would also be fun to do more with the “research proposals” that each group develops. By the time we were doing the presentations, we were so rushed that we barely had time to hear from every group, let alone critically analyze the proposed research. A followup discussion period, lab, or writing assignment could provide students the time they need to mold their original question, hypothesis, and methods into something interesting, important, and practical.
What about you? How do you tackle the biomes in your introductory biology class? Feel free to add your ideas in the comments section.