Cnidarians!!!!!!!!!!!!!!

1. Cnidarians!!!!!!!!!!!!!! http://www.youtube.com/watch?v=aJUuotjE3u8 Jellyfish, Hydroids, Corals, & Sea Anemones

10. Basic Information Radial symmetry Contain organisms such as jellyfish, hydroids, corals, and sea anemones Cnidocytes- stinging cells in their tentacles that are used for protection and killing prey.

11. Two Different Body Plans • 1. Polyp- mostly benthic, cylindrical, mouth is at one end and is surrounded by a ring of tentacles. • Ex- corals and sea anemones • 2. Medusa- free floating stage that is commonly known as a jellyfish.

13. Most of them do exhibit both during their life cycles, except corals and sea anemones • Both stages have the following: • Epidermis= outer layer of cells • Gastrovascular cavity that is rather large and is lined by cells called the gastrodermis. • Mesoglea- between the epidermis and gastrodermis and it’s a gelatinous material where jellies get their names from.

14. Stinging organelle-> called cnida and some function in locomotion while others function in capturing prey and defense. Most are of the spearing type called nematocycts= which is hidden away in a tiny capsule inside the cell and when activated it shoots out like a harpoon. When the cnidocil, a short bristle like structure, comes into contact with prey or another object, it gets activates and shoots out the nematocyst. Some nematocysts have a thread like structure that wraps around the prey and strangles them.

16. http://www.youtube.com/watch?v=BpKKGB-ivQo http://science.howstuffworks.com/zoology/jellyfish-videos-playlist.htm

17. Dangerous • Box Jellyfish- kills a person in minutes (3-20) • http://www.youtube.com/watch?v=uIf0kRpkQ_0 • Portuguese Man of War • http://www.youtube.com/watch?v=lem0RAVzVCM

18. Leatherbacks and Nudibranchs • Leatherbacks use them as a toy to play with and to eat! • http://www.youtube.com/watch?v=Rap3mnq0_lo

19. Nudibranchs • Feed on them and somehow store the nematocysts in their body and use them for their own defense. • http://video.nationalgeographic.com/video/animals/invertebrates-animals/other-invertebrates/nudibranch/

20. Hydrozoans Hydroids Colonial and share food Very small and usually inconspicuous Some are sessile and some are motile.

21. Jellyfish Class Scyphozoan or true jellies Swim by pulsating their bodies or floating in the currents (making them plankton). Sense organs= photoreceptors allow them to determine if it is dark or light. Many species do not like bright sunlight so they only come to the surface when its cloudy or near dusk.

22. Anthozoa Benthic Flower animals (bright colors)- sea anemones, corals, gorgonians (soft corals) Adults= sessile Only polyp stage

24. Sea Anemones Polyps Compartmentalized gastrovascular cavity Deepwater / shallow Sessile- some bury themselves in the mud like tube anemones

25. Sea Anemones Continue Expand tentacles to feed Contract their bodies when they are disturbed Change locations by gliding on their base, by crawling on their side, or walking on their tentacles. Some species can detach and swim with brief contractions.

26. Nutrition / Digestion / Feeding Digest their prey in the central gastrovascular cavity Two way digestive tract- food goes in and comes out the same way. Digestion and excretion are through the same crevice. Sessile- suspension feeders / filter feeders (plankton and organic matter) such as corals and anemones. Carnivorous- feed mostly on fish and larger invertebrates. Prey is paralyzed by the toxin in the nematocyst. Upside down jelly-> Cassiopeia, feeds on plankton that gets stuck in mucus produced by modified tentacles.

27. Cassiopeia

28. Ecological Roles Provide habitats like corals Key predators of the ocean Coral polyps: extremely important. They provide habitat for thousands of other organisms. The reefs provide a solid surface for sessile marine animals to attach to, place of refuge for fish, and they act as a buffer to protect coastal organisms from waves and storms.

32. Host Symbionts Portuguese Man of War and the Nomeus (man of war fish). Fish just swims amongst the tentacles without getting stung while gaining protection from the jelly, but it also lures other fish into the tentacles .

36. Host symbionts continues Zoozanthellae lives in corals and provides food to the coral as well as other reef fish. Parrotfishes- eat large amounts of coral polyps.

37. Sea Anemones Clownfishes Cleaner Shrimp Snapping Shrimp Arrow Crabs Brittle Stars Young anemones will attach to crabs as a form of camouflage.

38. Arrow Crab

39. Clownfish

40. Cleaner Shrimp

41. Snapping Shrimp

42. Ctenophora- The Comb Jellies (100-150 species known) No stinging cells Hermaphroditic- release sperm and eggs into the water. Planktonic , iridescent during the day and bioluminescent at night. Eight rows of cilia plates for locomotion, the plates beat allowing the animal to move. Carnivorous-> eats zooplankton, larval fish, and fish eggs. Ecological Role-> managing zooplankton size, regulation of fish species, and they channel nutrients to other species that eat them.

43. Ctenophore videos http://www.youtube.com/watch?v=G7WT81ukHZE http://www.youtube.com/watch?v=icKB9EfURhQ

47. Phylum Mollusca • Snails, slugs, oysters, clams, octopuses, squid, cuttlefish • Four Main Body Parts: • 1. Head- foot= head, mouth, sensory organs, and foot used for locomotion. • 2. Visceral mass= circulatory, digestive, respiratory, excretory, and reproductive systems. • 3. Radula- ribbon of tissue that contains teeth (bivalves don’t have these). Unique to mollusks and helps in scraping, piercing, tearing, or cutting food. • 4. Mantle- protective tissue that covers all of the soft parts. Also responsible for forming the animals shell by excreting calcium. Also used for gas exchange in some species.