1. Jellies, Corals, and Anemones
Chapter 7: CNIDARIANS:
Jellies, Corals, and Anemones

2. Cnidarians
Cnidarians are named because of the stinging cells they possess - cnidocytes
Cnidocytes produce organelles called nematocysts that actually sting the prey

4. Cnidarians Cnidarians are radially symmetrical.
Look the same from all sides and have no head, front, or back

5. Cnidarians have 2 ends:
Oral Surface
Aboral Surface

6. Anatomy & Physiology 2 tissue layers Intermediate “non-living” layer
Serves as support system
Single opening (mouth/anus) and no head

7. Cnidarians Cnidarians occur in 2 basic forms.
Polyp form: attaches to the bottom sediments, the mouth opens upwardly and is surrounded by a ring of tentacles
Medusa form: free-floating stage - commonly known as a jellyfish

9. Cnidarian: Classes 3 classes of cnidarians: Hydrozoans Scyphozoans
Anthozoans

10. Cnidarian: Hydrozoan Hydrozoans: colonial organisms
not true jellyfish.
Can be drifting polyps or siphonophores
Siphonophores like the Portuguese man-of-war are drifting colonies of polyps

11. Cnidarian: Scyphozoan
“true” jellyfish
have limited swimming abilities, so they depend on the currents
Spend most of their life as a medusa

12. Schyphozoan - cannon ball jelly

13. Scyphozoan - moon jelly

14. Scyphozoan - Sea Nettle

15. Scyphozoan - Upside-down jelly

16. Scyphozoan - Lion’s Mane:

17. Anthozoans:
Includes - sea anemones, corals, sea fans, sea pens, and sea pansies
EXCLUSIVELY polyp form
They can be very colorful - look like underwater flowers
Most complex cnidarian

18. Anthozoan - continued
They have strong muscles that allow them to extend and retract their tentacles - for feeding and avoidance of danger
Often are symbiotic
When two organisms create a union in which each is benefited by the other
Over time the clownfish becomes immune to the sting of sea anemones, then uses the anemone for protection

19. Anthozoans - Corals Two types - hard and soft corals
Hard corals secrete a calcium carbonate skeleton - which remains after death
Soft corals do not produce the rigid skeleton and look more like plants than animals - sea fans and sea pens are two examples

20. Polyp Anatomy

21. Coral Nutrition
Zooxanthellae provide nourishment for the coral through photosynthesis
Coral has an immense surface area for feeding (the entire reef)
Coral Reefs

22. Bartholomea annulata: Corkscrew Anemone
Description: thin, droopy tentacles that spiral
Distribution: Florida, Bahamas, Caribbean

23. Gorgonia ventalina: Common Sea Fan
Description:
single plane and fan shaped
Purple, yellow, or brown
Distribution
Florida Keys near coral reefs

24. Pennatulacea: Common Sea Pen
Description:
Resemble quill pens, will glow when touched
Distribution:
Shallow and deep water from polar waters to tropics

25. Renilla: Sea Pansy Description: Flattened, kidney-shaped Distribution:
Pacific and Atlantic coasts of North America

26. Montastrea annularis: Boulder Start Coral
Description:
Form dome-like tops
Large mounds
Shades of green, brown, yellow, and gray
Distribution:
Western Atlantic Ocean

27. Sponge and Cnidarian Video

28. Coral Reefs Economy Types Tourism Fishing Research Fringing Barrier
Atoll

29. Ecology Marine and Freshwater (Hydrozoa) All oceans, all depths
Symbiants
Shelter and food

30. Phylum Ctenophora (comb jellies)
Have eight rows of cilia on their outer body - used in locomotion
They do not have stinging cells!!!
They catch food by trapping it a sticky coating on their cilia or sucking in mouthfuls of water

31. COMB JELLY