Fifteen interdisciplinary lessons on marine invertebrates (mollusks, echinoderms, and jellyfish) are provided in this unit designed for students in kindergarten and in grades 1 and 2. Each lesson includes lesson concept, competency goals, objectives, materials needed, background information, teacher preparation, and activities suitable for use in science, mathematics, language arts, reading, art, and music classes. Activities are designed to foster development of inquiry, manipulative, organizational, creative, measurement, and communicative skills while students learn about specific animals (starfish, clams, oysters, scallops, sand dollars, and jellyfish) and: (1) that aquatic organisms are adapted to their environment in different ways; (2) that water provides habitats and protection for living organisms; and (3) that water provides a source of food, raw materials, and energy for human consumption. A packet of materials to be duplicated for student use is included. (JN)