Live-action footage conveys basic features of the major invertebrate groups, focusing on the body structure and physical features of simple animals. The following groups of invertebrates are addressed: poriferans, cnidarians, platyhelminthes, nematodes, annelids, mollusks, arthropods, and echinoderms. Other terminology includes: backbone, sponge, sea anemone, radial symmetry, planaria, earthworm, bilateral symmetry, exoskeleton, segmented body, and jointed appendages.