1. Phylum Porifera The Sponges Phylum Porifera

2. Phylum Porifera Overview • Most primitive of the multicellular animals • There is some debate if sponges are complex colonial protozans and not metazoans. • Sponges • Over 7,000 species, approximately 40 species that occur in local waters • 2% of all sponges are freshwater, none are terrestrial Phylum Porifera

3. Phylum Porifera Overview • Sponges occur in shallow water habitats and vary widely in size (up to 1m. high) and shape • All sponges are sessile filter feeders Phylum Porifera

4. Sponge Diversity Erect Rope Sponge Black-ball sponge Yellow Tube Sponge Phylum Porifera

5. Porifera Anatomy • Thin, flat cells, called pinacocytes, line the outer surface of a sponge. • Some pinacocytes are specialized into tubelike, contractile porocytes, which regulate water circulation. • Below the pinacocyte layer is a jellylike layer called the mesohyl Phylum Porifera

6. Porifera Anatomy • Mesenchyme cells move about in the mesohyl and can specialize to other functions including: • Reproduction • Secreting skeletal elements • Transporting and storing food • Forming contractile rings around openings in the sponge wall Phylum Porifera

7. Choanocytes Collar Cells • Choanocytes: (collar cells) act as a pump to bring water into the sponge • Create water currents for filter feeding Phylum Porifera

8. Sponge Support • Collagen is found between the inner canals and chambers • Mesohyl • Ameboid cells located in the mesohyl, have different roles • Archeocytes • Sclerocytes Phylum Porifera

9. Sponge Support Phylum Porifera

10. Spicules • Collagen is stiffened by adding microscopic mineral accretions or additional protein fibers (spongin) or both. • Spicules: skeleton structures, made of calcium carbonate (CaCO3) or silicon dioxide (SiO2). Spicules Phylum Porifera

11. Sponge Types- Ascon Phylum Porifera

12. Sponge Types- Sycon Phylum Porifera

13. Sponge Types- Leucon Phylum Porifera

14. Porifera Reproduction • Asexual budding • Regeneration: can regenerate from broken pieces • Gemmules- resistant capsules • Sexual • Usually hermaphroditic (monoecious) with male and female cells scattered throughout the connective tissue Phylum Porifera

15. Porifera Larvae • Neighboring sponges are fertilized by sperm entering through the ostia • Ciliated mouth less larvae (parenchymella) is released. Parenchymella Phylum Porifera

16. Sponge Life Cycle Phylum Porifera

18. Porifera Classification • Phylum Porifera • Class Calcarea • Class Demospongiae • Class Hexactinellida • Sclerospongiae is no longer considered a class Phylum Porifera

19. Class Calcarea • Have spicules made of calcium carbonate • Mostly small in size (<15 cm.), and form irregular masses • Never contain spongin, restricted to shallow water, and strictly marine Phylum Porifera

20. Class Demospongiae (Most sponges) • Have spicules made of silicon dioxide (SiO2) or spongin or a combination of both • Most sponges belong to this class (90%) • Nearly all are leuconoid body type • Mostly found on the continental shelf • Spongia spp. (Bath sponge) Phylum Porifera

21. Class Hexactinellida (Glass sponges) • Spicules are made of silica • Usually found in deep water on soft substrates in the tropics 200-1,000m. • Spicules are six pointed and have a lattice-like structure • Cup, vase or urn shape Euplectella (Deep sea Glass sponge) Phylum Porifera