1. Poriferans and Cnidarians

2. The “Tissue Animals” • Have tissues but no organs • Animal cell structure • Have embryonic stages of development

3. Phylum Porifera “Pore bearing” the sponges

4. Sponges • Epidermis • Mesenchyme • Amoebocytes • Spicules • Collar cells

5. Asexual Reproduction • Budding • Regeneration • Gemmules

6. Sexual Reproduction • A sperm from one sponge unites with an egg from another sponge and forms a zygote.

7. Phylum Cnidaria the hydra & jellyfish

8. The Cnidarians • Polyp • sessile body form • mouth and tentacles at one end; basal disc at other end • Medusa • bell-shaped, motile body form

9. The Hydra • Gastrovascular cavity • Two layers of cells • epidermis • gastrodermis • mesoglea

10. The Hydra • Tentacles • Cnidoblasts produce nematocysts.

11. The Hydra • Asexual reproduction • budding • regeneration • Sexual reproduction • testes, ovaries

12. Other Cnidarians • Jellyfish • Corals • Sea anemones: “flowers of the sea” • Portugeuse man-of-war