The Oyster: A Not-So-Typical Mollusc

Lab dissection of a representative of Class Bivalvia. Supported by several Shape of Life segments, students interpret bivalve adaptations as a radical case of divergent evolution: A simple ancestral snail with a mobile lifestyle, single dome-shaped shell, bilateral symmetry, and a head (“cephalization”) transformed into a headless, double-shelled, sedentary filter-feeder whose bilateral form is obscure.

We provide both high school and middle school versions of this lesson. The instructor's guide applies to both versions.

This lesson was created by Kevin Goff, Virginia Institute of Marine Science educator.