WARM UP Draw a picture of a sponge, showing the ostia, osculum, and collar cells.

Cnidarians Notes Phylum Cnidaria

General Characteristics 9,000 aquatic species  Stinging cells Radial symmetry

Structure Inner layer Outer layer Digestive cavity Single opening Nematocysts in tentacles Radial symmetry

Structure Body Forms Polyp Medusa Sessile, tube shaped Free-swimming “umbrella”

Feeding Nerve net detects impulses Sting and bring in prey All digestion in gastrovascular cavity

Reproduction Asexual Budding Sexual External fertilization

Classification Class Scyphozoa Jellyfish Medusa dominant

Classification Class Anthozoa Corals and anemones Polyp dominant

Classification Class Hydrozoa Portuguese man o’ war Colonies

WRAP UP Classify each of the following pictures into the appropriate Class of cnidarians.