1. Phylum Porifera The Sponges

3. Phylum Porifera Simplest of all multicellular animals
Cellular level of
organization

4. Characteristics of Porifera
Size: 2mm to 2m
Colorful
Mostly marine, all aquatic
Radial symmetry or none

5. Characteristics
Both sexual (release sperm into water, embryo becomes a swimming larva) and asexual reproduction (fragmentation)
Sessile
Pore bearing
Canals

6. Basic Structure

7. Filter Feeders Sessile
Water currents carry food and oxygen in and waste out
Choanocytes: collar cells that beat flagella for water flow to capture fod
Osculum: opening at top through which water exits

8. Classified by type of Spicules

9. Class Calcarea Spicules of calcium carbonate Straight or 3 or 4 rays
Tubular or vase shaped
10 cm or less

10. Class Hexactinellida Glass sponges Spicules are 6 rayed 7.5 cm to 1.3m
Tubular or vase shaped

11. Class Demospongiae Most sponges
Spicules are siliceous, but not 6 rayed
Diverse shapes
Bath sponges (no spicules)