PHYLUM PORIFERA (Sponges)• “Porifera” means pore – bearing• lacks true tissues & organs; incomplete digestive system• has skeleton that supports & protects the body; made up of “spicules”
PHYLUM CNIDARIA• Radially symmetric• digestive chambers with a single opening, which serves as both mouth & anus• Includes: hydras, jellyfish, corals and sea anemones
PHYLUM CNIDARIA2 body forms: polyp form and medusa form 1. polyp form - cylindrical; mouth & tentacles at the upper end 2. medusa form – shaped like an upside-down bowl; mouth & tentacles facing downwardhas tentacles with stinging cells called “cnidocytes”that paralyzes their preys Jellyfish -medusa Coral - polyp
PHYLUM PLATYHELMINTHES (Flatworms)• with flattened bodies; bilateral symmetry• lacks body cavity• most flatworms are parasites
PHYLUM PLATYHELMINTHES (Flatworms)• 3 major groups: flukes, planaria & tapeworms 1. Flukes – parasites that absorb the nutrients from the body of a host harming it; causes a disease called schistosomiasis 2. Planarians – non-parasitic, lives in moist environments & free-living 3. Tapeworms – long ribbon-like flatworm; can infect humans through eating undercooked meat of an infected cow or pig
PHYLUM NEMATODA (Roundworms)• has cylindrical bodies tapered at both ends & covered by a tough cuticle• includes parasitic types: trichina, filaria, pinworms, & hookworms• Many are introduced through poorly cooked pork or walking barefoot in contaminated areas.• Some diseases caused by roundworms: elephantiasis, trichinosis.