1. Chapter 9.3 Sponges and Cnidarians

2. POINT > Describe characteristics of sponges POINT > Describe characteristics of a cnidarians POINT > Describe two stages of cnidarian life cycle POINT > Emphasize the importance of coral reefs

3. POINT > Describe the characteristics of sponges Sponges are the simplest animals Cellular level of organization (no tissues or organs) No symmetry Live in fresh and salt water Water flows in through the cells and out through the top. Single-celled organisms are filtered out of the water for food

4. POINT > Describe the characteristics of sponges Choanocytes are cells that move water through the sponge Sponges reproduce both asexually and sexually

5. CHECK: What kind of symmetry do sponges have? What level of organization to sponges have? What are choanocytes? Where do sponges live?

6. POINT > Describe characteristics of cnidarians Cnidarians include jellyfish, hydra, anenomes and corals

7. POINT > Describe characteristics of a cnidarians Cnidarians have radial symmetry Tissue level of organization: simple nervous and muscle tissue Have stinging cells called nematocysts for capturing prey Have a mouth and digestive cavity to eat prey Reproduction is both sexual and asexual (budding)

8. POINT > Describe two stages of cnidarian life cycle Cnidarians have a two-stage life cycle: 1. Polyp – lives attached to rock or lake bed

9. POINT > Describe two stages of cnidarian life cycle Cnidarians have a two-stage life cycle: 2. Medusa – free swimming

10. POINT > Describe two stages of cnidarian life cycle

11. CHECK: What type of symmetry to cnidarians have? What are 3 types of cnidarians? What are the two stages in cnidarian life cycles? What are nematocysts?

12. Polyp or medusa?

14. Coral reef

15. POINT > Emphasize the importance of coral reefs Corals are cnidarians that live in colonies Coral reefs are made of the dead skeletons of the coral Coral reefs provide habitat for fish and other organisms in the oceans Most of the oceans’ biodiversity exists in coral reefs

16. POINT > Emphasize the importance of coral reefs Coral reefs are being destroyed rapidly by pollution, over- fishing and increases in water temperatures and acidity Large reefs in the Caribbean and South Pacific ocean have experienced 40-90% loss over the past 10 years

17. Homework: Read pages 303-311 Section Assessment Page 311 #1-3 GRAS Pages 129-131