Phylum Cnidaria & Ctenophora

1. Phylum Cnidaria & Ctenophora Kingdom: Animalia Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Anthozoa Phylum Ctenophora

2. Major Characteristics • Presence of specialized tissues • Also called Coelenterates • Comprised of sea anemones, jellyfish, corals • Have radial symmetry • Two forms polyps and medusa

3. Body Structure • All have radial symmetry, where similar parts of the body are arranged and repeated around a central axis

4. Radial vs. Bilateral Symmetry Diagram A

5. Radial Symmetry

6. Two Main Body Forms - Polyp • A polyp is a sac like stage. • Sessile or non-motile

7. Two Main Body Forms - Medusa • A medusa is bell-like, which is similar to an upside down swimming polyp • Free floating or swimming

8. Polyp vs. Medusa • Some spend their life as both at some point or as one or the other the entire time Diagram B

9. Polyp vs. Medusa Diagram D

10. Three Basic Layers:

11. Three Basic Layers • Ectoderm/Epidermis – outer layer that contains the stinging cells • Endoderm/Gastrodermis – lines the gut • Mesoglea – Jelly like substance in between the Ectoderm and Endoderm which contains scattered cells and collagen fibers

12. Exoskeleton • Coral will create a calcium carbonate shell in which it will live

13. Body Structure • The mouth is located on the top of the polyp or underside of the medusa • It is the only opening on the organism so is also shares the function of being an anus Diagram E

14. Body Structure Diagram F

15. Tentacles • Slender finger like structure used to capture and handle food • Location of nematocysts

16. Nematocysts • The main characteristic of Cnidaria is the presence of nematocysts • Stinging structures found on the tentacles

17. Nematocysts • Coiled – like stinger • Spring into the prey and releases toxin • Most not harmful to humans because they cannot penetrate skin • Some fatal

18. Nervous System • Main characteristic is the presence of a nerve net • Nerves cross over each other, at every connection, communication occurs • In humans millions cross over millions and no communication occurs

19. Nerve Net Diagram C

20. Digestive System • All cnidarians are carnivorous • Paralyzed by the nematocysts • Enzymes in gastric cavity break down the food and nutrients are absorbed by cells in the endoderm • Wastes are sent out the mouth/anus

21. Digestive System

22. Reproductive • Cnidarians have the ability to reproduce sexually and asexually • One method that is commonly seen is budding

23. Class Anthozoa • Largest group of Cnidarians • Stay in the polyp stage throughout life cycle • Solitary or colonial • Includes sea anemones

24. Class Hydrozoa • Can consist of just a polyp stage, just a medusa stage, or both • Can join together to form complex colonies such as the Portuguese Man-O-War, which develop floats FLOAT

25. Class Scyphozoans • Medusa is the dominant life stage • Swim with rhythmic contractions of the bell, though limited • Contain the most dangerous/fatal stings BELL

26. Phylum Ctenophora • Comb Jellies • Not a member of the Cnidarian Phylum even though they share similarities

27. Cnidaria vs. Ctenophora Ctenophora • Have cilia at the base of the medusa to move • Engulf food • Do not have nematocysts • Have an additional layer between endo and ecto layers • Anal pore