Part of the "Branches on the Tree of Life" series. Imagine an animal with no mouth, no digestive system, no excretory or circulatory organs, no brain nor nervous system, and no movement as an adult. In spite of their simple nature, sponges are actually one of the most interesting animal phyla when viewed in developmental, ecological, and evolutionary terms. Clarifies the structure, function, classification, and ecological roles of sponges through animations and time-lapse microscopy. Accessibility options on the DVD are: (1) expanded description, (2) English subtitles in a black box, (3) subtitled description.