Tuesday, October 4, 2011
Cacti Adaptations Model
After reading Cactus Hotel, a wonderful book about the desert ecosystem, food chains in the desert, and cactus adaptations, my students created a model cactus to bring the adaptations to life. As the Styrofoam balls were being painted green, we talked about chlorophyll and its role in photosynthesis. We recalled why many desert plants either don't have leaves (like cacti) or have very small ones (to reduce water loss). The fleshy nature of cacti was also discussed as a water storage feature. Once the balls were dry, the spikes were added. Students were given lengths of floral wire to cut into short pieces. These were poked into the cactus at even distances around it. As they did this, students talked about the protection these provided, both from hungry/thirsty herbivores and subtle shade that is provided. Small, square tissue paper flowers were then added. (Use a pencil with an eraser to shape the tissue paper, dab in glue, and set.) While students did this, we talked about the role of flowers—to attract pollinators. Although we did not make the fruit that follows pollination, we discussed its purpose too—to attract animals that will eat it and spread the seeds to continue the survival of the species. My students were extremely proud of their creations and did exceptionally well on the assessment for cactus (and other plants) adaptations.