1. Phylum Porifera – Characteristics Multi-cellular, but cells totipotent; evolutionary origin likely from colonial Protozoa (choanoflagellates); good fossil record from as early as Cambrian; asymmetrical, but many vase-shaped with excurrent hole (osculum) Cell Differentiation Choanocyte: “collar cell” with flagellum and microvilli Archaeocyte: amoeboid cell; can differentiate into sclerocytes (secrete spicules) and other cell types Pinacocyte: flattened, epithelial-like cell; form pinacoderm (epithelium) Body Structures (increasing efficiency of filtration) 1. Asconoid: choanocytes in central chamber (spongocoel) 2. Syconoid: choanocytes in canals leading to spongocoel 3. Leuconoid: choanocytes in multiple chambers

3. Newly Discovered Sponge Species: Bobospongia isrealensis

4. CO 12

5. Fig. 12.1 FIGURE 12.1, page 248

6. Fig. 12.9

7. Fig. 12.2

8. Fig. 12.5

9. Phylum Porifera – Diversity and Physiology Diversity: ~ 15,000 extant species, most marine Class Calcarea: spicules are calcium carbonate; small sponges (< 10 cm high); ex. Scypha, Leucosolenia Class Hexactinellida (Glass Sponges): six-rayed siliceous (SiO 2 ) spicules, often bound together in network ; ex. Euplectella Class Demospongiae: 95% of sponge species; siliceous spicules and/or spongin; ex. Spongia (bath sponges) Physiology Reproduction: asexually via external buds or gemmules, or sexually with sperm and oocytes (most sponges monoecious); most with planktonic larval stage (parenchymula) Feeding: most are suspension feeders; some in nutrient-poor waters are carnivorous; others contain photosynthetic endosymbionts Many harbor commensal organisms; few predators (ex. angelfishes)

10. Fig. 12.4

11. Fig. 12.3

12. Fig. 12.11

13. Fig. 12.12

14. Phylum Cnidaria – Characteristics Cell Types: cnidocytes (stinging cells) contain nematocysts (venom-injecting barbs); sensory and nerve cells; few with muscle tissue Body Forms: sessile, attached polyp, and free- swimming or planktonic medusa; both exhibit radial symmetry; polymorphism common in colonial hydroids (siphonophores, ex. Physalia) Life Cycles: zygote develops into planula larva, which settles on substratum and develops into polyp; polyp produces medusae in most taxa; some without medusa stage (ex. sea anemones)

15. Fig. 13.4

16. Fig. 13.6

17. Fig. 13.3

18. Fig. 13.7

19. Fig. 13.12

20. Phylum Cnidaria – Diversity and Physiology Diversity Class Hydrozoa (hydroids; hydrocorals): most marine and colonial Class Scyphozoa (jellyfishes): most marine; adult is medusa Class Cubozoa (box jellyfishes): all marine; Chironex fleckeri deadly Class Staurozoa: stalked polyp with medusa-like appearance Class Anthozoa (corals, sea anemones, sea pens, sea pansies): all marine; no medusa stage Physiology Reproduction: asexual via budding or fission; medusae typically sexual; polyps of anthozoans reproduce either sexually or asexually Feeding: capture prey with tentacles (sting); gut with mouth only (four gastric pouches in jellyfishes); hermatypic (reef-building) corals obtain sugars from endosymbiotic dinoflagellates Coral Reefs: built by scleractinian corals; secretions of calcium carbonate based on relationship with mutualistic endosymbionts (zooxanthellae) Reef Evolution (Darwin): Fringing reefs  Barrier reefs  Atolls

21. Hydroids - Diversity

22. Class Staurozoa  Class Scyphozoa

23. Fig. 13.21 – Class Cubozoa

24. Class Anthozoa - Diversity

25. Class Anthozoa - Diversity of Corals

26. Fig. 13.2

27. Fig. 13.11

28. Fig. 13.19

29. Fig. 13.24

30. RED CLONE YELLOW CLONE ORANGE CLONE

31. Fig. 13.28

32. Fig. 13.32

33. Fig. 13.35

34. Phylum Ctenophora – Characteristics and Diversity Characteristics: bi-radial symmetry; eight rows of ctenes (combs of cilia); most capture prey with two tentacles armed with adhesive cells (colloblasts); iridescent and luminescent (used in transgenics) Diversity About 150 species; entirely marine (major component of gelatinous zooplankton) Common names: comb jellies, sea walnuts Examples: Pleurobrachia, Beroe (predator), Cestum Population explosions of Mnemiopsis leidyi have led to fishery declines; spread via ship ballast

36. Fig. 13.37

37. Fig. 13.39