A Survey of Marine Animal Kingdoms Phylum Cnidaria Has Diversity Hydroids Jellyfish Sea Anemone Coral polyps 2 2 Corals, Anemones, Sea Fans and Jellyfish Phylum Cnidaria Radial symmetry symmetry around a central point Two body forms: Medusa jellyfish Polyps Corals, sea anemones Two tissue layers Outer epidermis and inner gastrodermis Hollow gut -Gastrovascular cavity has single opening (serves as both mouth and anus) 1
Two Main Body Plans of Cnidarians TENTACLES HANG DOWN epidermis mouth UPRIGHT TENTACLES Polyp mesoglea Medusa gastrodermis Mesoglea THICK Mesoglea THIN 4 5 5 Cnidarian Characteristics Either tubular or bell shaped Tentacles surround mouth Only animal with cnidocytes (stinging cells) found in the tentacles Nematocyst coiled, harpoonlike stinger inside cnidocyte that shoots out 6 6 2
Cnidarian Digestion Cnidocytes contain proteins to paralyze prey Tentacles or oral arms bring food into mouth Inner gastrodermis secretes digestive juices into gastrovascular cavity, which digests food and circulates nutrients 7 7 Cnidocyte Coiled nematocyst 8 Nematocyst Barbed, threaded stinger capsule s lid trigger nematocyst 9 9 3
Nematocysts in action! 11 11 Cnidarian Nerve Systems Have a simple nerve net & sensory receptors Muscles help in directional movement & capturing prey 12 4
Alternate life cycles Solitary polyp or medusa Colonial forms floating or attached to bottom Interesting life cycles Sexual: broadcast spawning Assexual: budding or fragmentation Cnidarian Reproduction Hydroids and Jellyfish switch between medusa and polyp Hydrozoan Life Cycle Most hydrozoans alternate polyp and 14 medusa forms, as this hydroid, Obelia 14 Coral Reproduction Asexual Budding Fragmentation Growth after Fragmetation Sexual Gametes released by broadcast spawning produce a planulae 5
Coral Reproduction Coral Reproduction Scyphozoans: Jellyfish Box Jellyfish (Cubozoa) Anthozoans: Sea anemones Corals Hydrozoans: Hydra Siphonophores Cnidarian Diversity 18 6
Scyphozoans 19 Jellies near and far Lion s mane Jellyfish Extremely sticky tentacles may trail as long as 30 m (100 ft) or more. These tentacles are grouped into eight clusters, each cluster containing over 100 tentacles, [ arranged in a series of rows. Aurelia aurita Moon Jelly SEMAEOSTOMAE Drymonema dalmatinum Jellyfish Predation Pink Meanie 7
Aurelia swarm RHIZOSTOMAE Cannonball Jellyfish Cassiopeia xamachana Upside down Jellyfish Cassiopeia frondosa Stomolophus meleagris Sea Nettles 24 8
Types of Cnidarians: Cubozoa Types of Cnidarians: Cubozoa Box jellies a.k.a. sea wasps Venom attacks heart, nervous system, and skin cellsà dead w/in minutes One of the deadliest venoms on earth Common to Northern Australia, Southeast Asia, and the Indian Ocean What are sea lice? Low-power photomicrograph of thimble jellyfish larva Larva firing nematocysts (stinging cells) after pressure from a cover slip is applied http://www.fau.edu/safe/sea-lice.html 9
Hydrozoans Hydra Exist only as polyps Reproduce by budding, never live as free-floating medusa Freshwater genus Form resistant zygotes when environment is bad Move by somersaulting with tentacles 28 Hydra Feeding 29 29 Food in Gastrovascular Cavity 30 10
HYDROZOA: Fire Coral, Hydrozoans Macrorhynchia philippina Manubrium Colonial hydrozoans have a base, a stalk, and at least one polyp, Medusa mature and release gametes, which fuse to form zygotes, which grow into freeswimming planula larvae upon settling on a suitable substrate develop into a hydroid colony by asexual reproduction. Types of Hydrozoans: Siphonophores Form drifting colonies of polyps (Not a single organism!!) Some have specialized gas filled float Example: Portuguese man-of-war Up to 165 ft tentacles! Can be Deadly Porpita porpita Velella velella Above: By-the-wind Sailor Left: Blue button Floating hydrozoan polyps 11
Not True Jellies: Comb Jellies Phylum Ctenophora a.k.a. ctenophores Have 8 rows of ciliary combs Refracts light, creates a prism-like multicolor effect Carnivores Sticky colloblasts catch prey and allow organism to swallow it whole No nematocysts Ctenophore 35 Anthozoans 36 12
Types of Cnidarians: Anthozoans Sea Anemones Brightly colored & Resemble flowers Solitary polyps Feed on invertebrates & fish Corals Most are colonial Build limestone (CaCO3) skeleton Live as polyps in corralite hole 37 Common Caribbean Anemones Giant anemone, Condylactus gigantea Symbiotic host With cleaner shrimp Corkscrew anemone, Bartholomea annulata Peterson cleaner shrimp Distribution of Coral Reefs 39 13
WHAT IS A CORAL? Phylum: Cnidaria Shared characteristic between corals and jellyfish are the individual coral animal Multiple polyps live together in what is called a coral CRF/Jessica Levy h"p://artwanted.com/imageview.cfm?id=336826 Symbiotic zooxanthellae algae cells live with coral for a mutualistic relationship CORAL ANATOMY Mouth Tentacles with nematocysts Zooxanthellae Calcium carbonate skeleton Coenosarc Living Tissue Nematocyst Symbiotic relationship with ZOOXANTHELLAE Housed within coral tissue Source of nutrients Skeleton 2010 Encyclopedia Britannica, Inc. Stomach Smithsonian Institute 14
Mutual Symbiotic Relationship: Both Coral and Zooxanthellae Benefit each other Coral tissue Waste Carbon Water dioxide Zooxanthellae Protection Lipid and habitat production Glucose Oxygen Adapted from NOAA, 2008 TYPES OF CORALS REEF BUILDING Gorgonians SOFT CORALS h"p://www.coralreefphotos.com/macro- view- of- endangered- staghorn- coral/ h"p://h"p://eastep.photoshelter.com/image/i0000mghl0b.4zgq/ TYPES OF CORALS: STONY CORALS REEF BUILDING SOFT CORALS h"p://www.coralreefphotos.com/macro- view- of- endangered- staghorn- coral/ h"p://h"p://eastep.photoshelter.com/image/i0000mghl0b.4zgq/ 15
Brain Coral Star Coral STAGHORN AND ELKHORN Acropora cervicornis The white tips on both the Staghorn and Elkhorn corals indicate good health there is new coral skeleton growing! Reefs of the past were dominated by healthy thickets of staghorn and elkhorn coral. Acropora palmata 16
STAGHORN AND ELKHORN DECLINE Decline of coral cover alters the ecosystem services reefs provide to coastal communities. These corals have declined by 98% throughout the Atlantic and Caribbean. CHANGES IN REEFS OCEAN WARMING OCEAN ACIDIFICATION CORAL WATER DISEASE QUALITY LOSS OF HERBIVORES RESTORATION OUTPLANTING 17
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