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Skulls & Scatterplots: Students Analyze Sloth Body Size Variation in the Bocas del Toro Island Region

The Science Teacher—July/August 2024 (Volume 91, Issue 4)

By Tyler St. Clair, Kristen Conklin-Kearney

In this unit, students explore the phylogeography of three-toed sloths (Bradypus pygmaeus and Bradypus variegatus) endemic to the Bocas del Toro islands off the Caribbean coast of Panama. After learning about the geologic history of this region, students measure model sloth skulls from each of the islands and compile that data into scatterplots. Students then analyze the scatterplots to make conclusions about which geographic factors best account for the variance in sloth body size in the region. The sequence of activities was designed for high school life science classrooms using the Next Generation Science Standards (NGSS) framework and teaches the disciplinary core idea LS3.B Variation of Traits. This lesson was taught in an integrated co-teaching classroom, a special education classroom, and a ninth-grade general biology classroom. Students were able to successfully answer the overarching research question and gained a deeper knowledge about natural selection and evolution in the process.

Biology Interdisciplinary Teaching Strategies High School

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