WARM UP Describe two or three ways jellyfish are more like “traditional” animals than sponges.

Phylum Platyhelminthes Flatworms Notes Phylum Platyhelminthes

General Characteristics Flattened bodies Single gut opening Digestive organ Nervous organs Cephalization

Planarians Free-living Reproduction Moist habitats Move with cilia Eyespots and nervous control Reproduction Asexually divide Sexually with internal fertilization

Flukes Parasites Multiple stages and hosts in life cycle Blood fluke Liver fluke Swimmer’s itch

Tapeworms Intestinal parasites Use scolex to attach Grow by adding body segments (proglottids) Each has sperm and eggs Fertilized segments break off

WRAP UP List three or four advancements in the structure and function of flatworms (especially planarians) that make them more advanced than the Porifera and Cnidaria.