Crabs and Barnacles

Gr all levels—This flexible teaching tool can be used in science classes from elementary school through high school. It places crabs and barnacles within the phylum arthropoda, showing how they are related to spiders and insects. Their physiology, habitats, diets, defense mechanisms, and life cycles are explored. The film shows how barnacles and crabs molt and where they fit into the food chain. It also touches on how crabs and barnacles are viewed from an economic standpoint. Crabs are a popular food, and barnacles, which attach themselves to ships, have created an entire industry devoted to their removal. Visuals consist of some video clips and many still images of varying quality. The life cycle sequences are animated by superimposing a still photograph or line drawing over a video of an underwater scene. The female narrator has a pleasant, voice and speaks slowly so that students have time to take notes. There is a menu for each grade level—high school, middle school, and primary grades. The high school version about crabs and barnacles uses appropriate vocabulary and includes a sequence about how the animals mate. The two other versions use less sophisticated vocabulary and omit the mating sequences. Teachers also have the option of showing only the segment on crabs or barnacles. The primary grade version can be shown with narration over music or just with background music. A nice addition to science classrooms.—Geri Diorio, The Ridgefield Library, CT