1. Corals, Anemones, Sea Fans, and Jellies Phylum Cnidaria The Stingers Box Jellyfish - Irukandji - YouTube

2. Characteristics Radially symmetrical: repeating units around a central point

3. Characteristics continued Mesoglea: layer of jelly separating two tissue layers of cup or umbrella-shaped body Gastrovascular cavity: space in middle of the body for digestion and reproduction, often surrounded by tentacles

4. Characteristics contd Tentacles usually lined with several different types of nematoblasts, which produce structures called nematocysts May be mucus coated to entrap prey Some have deadly poisons to stun or kill prey

5. Nematocyst firing

6. Two Body Forms Polyp: organisms that are attached with oral surface pointed upward(e.g. corals and sea anemones) Medusa: free-floating, with oral (mouth and tentacles) surface typically pointed downward (e.g. jellies)

7. Class: Anthozoa (Corals and Anemones) Largest class in the phylum Cnidaria Includes more than 6,000 species All are polyps Some are colonial (corals, soft corals), others are individual (anemones, a few corals) Red Gorgonian, colonial coral, NOAA Close up of a coral colony

8. Coral life cycle

9. Hard corals and dinoflagellates The color of hard corals comes from the dinoflagellates in the genus Symbiodinium, also called zooxanthellae These organisms live inside coral, provide food and help eliminate waste through photosynthesis Zooxanthellae living inside coral

11. Coral bleaching Zooxanthellae live best in well- lit, clear water Thrive in low-nutrient, less productive waters (with little plankton to block the sunlight) Runoff of pollution can cause plankton to grow and zooxanthellae to die Without zooxanthellae, corals lose their colors = coral bleaching Global Warming & Bleaching the Reef - YouTubeGlobal Warming & Bleaching the Reef - YouTube

12. Class: Hydrozoa (Fire Corals and Siphonophores) Immortal Jelly Immortal Jelly Alternate between polyp and medusa forms during their life cycle

13. Ex. Fire corals Fire corals—create a mild burn upon contact Waxy, tan appearance and grow in small tree- like colonies or as an encrusting colony on an existing reef 'The Fire Coral' Pt. 1 - YouTube

14. Siphonophores One species measured to be a total length of 40 m (131 ft) Many represent a bridge between colonial animals and complex organisms –Exist as colonies –Within colonies are special polyps adapted to feeding, reproduction, movement, and other functions Major predators with some consuming significant quantities of krill Example: Portuguese man- of-war

15. Portugese Manowar - YouTube

17. True Jellies Class: Scyphozoa Class: Cuboza

18. Class: Scyphozoa (true jellies) Range in size from smaller than a coin to more than a meter across with tentacles more than 3 m long Most are large planktonic organisms that swim but also drift with the current Weak swimmers, move by contracting their rounded body, or bell Feed on almost anything they catch

19. Reproduction Scyphozoa life cycle alternates between sessile and freefloating Juveniles are polyps, adults are medusas

20. Scyphozoa continued Efficient predators Prey for Leatherback turtle and several species of large fish—predators move seasonally with jellies Plastic bags, balloons, and small trash often are mistaken by turtles as jellies and can harm them by clogging their digestive systems

22. Class Cubozoa Box Jellyfish are pale blue and transparent and bell or cube shaped with four distinct sides, therefore the name box jellyfish.

25. up to 20 cm along each side of the cube or bell up to as many as 15 tentacles on each corner which can be 3 metres in length with up to 5,000 nematocysts (stinging cells). Box Jellyfish feed on small fish and crustaceans. Cubozoa continued

26. The box jellyfish has four sets of eyes, each set at one corner of the animal

27. Cubozoa continued can be found in Australia, the Philippines, Indonesian Coast, Hawaii, Vietnam, the Carribean and other tropical areasAustraliaPhilippines Indonesian CoastHawaiiVietnam Carribean

28. Anemone symbiosis Found in the tropical Indo-west Pacific or tropical Pacific, Indian Ocean, and Red Sea Anemonefish (e.g. clownfish) receive protection by living amongst the stinging tentacles Fish passes back and forth through the tentacles to pick up anemone cells, the anemone recognizes its own cells on the fish so doesn’t sting it

29. The anemone has not be shown to benefit from this association, therefore the relationship is one of Commensalism

30. Biology of Cnidarians Typically carnivores Extracellular/intracellular digestion Nerve net statocysts