phyla+cnidara+and+ctenophora

ZOOLOGY NOTES—CNIDARIA AND CTENOPHORA

PHYLUM CNIDARIA—JELLYFISH, SEA ANEMONES, AND CORALS

CNIDARIAN FACTS CNIDARIAN CHARACTERISTICS ü ALL ARE AQUATIC; MOSTLY MARINE ü RADAIAL SYMMETRY ü THERE ARE TWO BASIC BODY TYPES—POLYP AND MEDUSA ü THE BODY CONSISTS OF TWO TISSUE LAYERS (ECTODERM AND ENDODERM) WITH A JELLY-LIKE LAYER CALLED THE MESOGLEA IN BETWEEN ü THE BODY HAS A HOLLOW CAVITY CALLED THE GASTROVASCULAR CAVITY WITH A SINGLE OPENING CALLED THE MOUTH, WHICH ALSO SERVES AS THE ANUS ü THE MOUTH IS TYPICALLY SURROUNDED BY TENTACLES WHICH AID IN CAPTURING FOOD ü TENTACLES ARE TYPICALLY COVERED BY **CNIDOCYTES**  THESE STINGING CELLS CONTAIN SPECIAL ORGANELLES CALLED NEMATOCYSTS  THE NEMATOCYST IS A CAPSULE CONTAINING A TINY COILED FILAMENT WHICH SHOOTS OUT AND POISONS THE CNIDARIAN’S PREY  OVER 20 DIFFERENT TYPES OF NEMATOCYSTS ARE KNOWN AND ARE IMPORTANT IN CLASSIFICATION ü A ‘NERVE NET’ IS PRESENT, BUT NO BRAIN ü MUSCLE CELLS AID IN SWIMMING ü RESPIRATION OCCURS AS GASES ARE EXCHANGED WITH THE WATER ü BOTH SEXUAL AND ASEXUAL REPRODUCTION OCCURS—GAMETES ARE FORMED IN SEXUAL REPRODUCTION AND BUDDING IS THE TYPCIAL FORM OF ASEXUAL REPRODUCTION ü MANY ALTERNATE BETWEEN THE MEDUSA AND POLYP STAGE
 * MORE THAN 9000 KNOWN SPECIES
 * NAME DERIVED FROM THE GREEK WORD ‘CNIDO’ WHICH MEANS ‘STINGING NETTLES’
 * ALL HAVE SPECIAL STINGING ORGANELLES CALLED NEMATOCYSTS

REPRESENTATIVE CNIDARIANS

CLASS HYDROZOA o MOST ARE COLONIAL AND MARINE—AN EXAMPLE IS //Obelia// <span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o A FEW, SUCH AS THE HYDRA, ARE FRESHWATER POLYPS WHICH HAVE NO MEDUSA STAGE EXAMPLES—//Hydra, Obelia, Physalia// // Hydra // <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v //Hydra// is a solitary (non-colonial) polyp <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v Sixteen different species are found in North America <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v Their favorite food is //Daphnia//, a small crustacean whose common name is the water flea // Obelia // <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø This marine colonial hydroid looks much like a plant <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø It consists of many individuals called zooids <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø Feeding polyps of this organism are called hydranths <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø New medusae form in a reproductive polyp called a gonangium // Physalia // <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ This colonial hydrozoan is known as the Portuguese man-of-war <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ Many polyps are suspended from a float filled with a gas similar to air <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ Found in tropical seas, they are commonly seen along the Eastern Coast of the United States <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">§ A small fish, //Nomeus//, has a mutualistic relationship with the man-of-war—why it is not stung is not clear

CLASS SCYPHOZOA <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;"> TRUE JELLYFISH <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;"> MOST ARE SMALL, AND FOUND FLOATING IN THE OPEN OCEAN EXAMPLE—//Aurelia// // Aurelia //
 * Common name is the moon jelly
 * Commonly found off both the East and West Coasts of the United States

CLASS CUBOZOA CLASS ANTHOZOA <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v THIS GROUP IS VERY DIVERSE AND CONSISTS OF SEA ANEMONES AND CORALS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">v THESE ‘FLOWER ANIMALS’ ARE ALL POLYPS AND FOUND IN OCEANS ALL OVER THE WORLD, IN BOTH DEEP AND SHALLOW WATER
 * TINY CNIDARIANS WHICH TYPICALLY EXIST AS A MEDUSA
 * THE BELL IS ALMOST SQUARE
 * SOME SPECIES CAN BE DEADLY TO HUMANS
 * THE SEA WASP, //Chironex fleckeri,// CAN BE DEADLY. MOST FATAL STINGS HAVE BEEN REPORTED IN TROPICAL WATERS OFF THE COAST OF AUSTRALIA

CLASS ANTHOZOA, SUBCLASS HEXACORIALLIA <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü THIS GROUP CONSISTS OF SEA ANEMONES AND HARD CORALS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü THE TENTACLES ARE FOUND IN MULTIPLES OF SIX <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">ü THE POLYPS ARE LARGER AND HEAVIER THAN THOSE OF HYDROZOANS MUTUALISM IN SEA ANEMONES:
 * 1) ANEMONES HAVE A MUTUALISTIC RELATIONSHIP WITH CLOWN FISH
 * 2) A SKIN MUCUS PRODUCED BY THE FISH APPARENTLY CAUSES THE NEMATOCYSTS NOT TO DISCHARGE
 * 3) ANEMONES AND CORALS ALSO FORM A MUTUALISTIC RELATIONSHIP WITH CERTAIN ALGAE (ZOOXANTHELLAE) AND BENEFIT FROM THE PRODUCTS OF THE ALGAL PHOTOSYNTHESIS

CLASS ANTHOZOA, SUBCLASS CERIANTIPATHARIA—TUBE ANEMONES

CLASS ANTHOZOA, SUBCLASS OCTOCORILLIA <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;"> THIS GROUP HAS EIGHT TENTACLES AND CONSISTS OF ALL COLONIAL POLYPS

CORAL REEFS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø THESE ECOSYSTEMS HAVE A DIVERSITY RIVALED ONLY BY THE TROPICAL RAINFOREST <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø THEY ARE FOUND IN WARM, SHALLOW WATERS AND CONSIST OF LARGE FORMATIONS OF CALCIUM CARBONATE SECRETED BY THE LIVING ORGANISMS <span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings; msobidifontfamily: Wingdings; msofareastfontfamily: Wingdings; msolist: Ignore;">Ø ONLY THE OUTER LAYER IS ACTUALLY ALIVE

PHYLUM CTENOPHORA—THE COMB JELLIES <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;">· THIS GROUP CONSISTS OF FEWER THAN 100 SPECIES <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;">· NAMED FOR THE EIGHT ROWS OF COMBLIKE PLATES THEY USE FOR LOCOMOTION <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;">· COMMON IN SURFACE WATERS, THEY CAN ALSO BE FOUND IN DEEP OCEANS <span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msofareastfontfamily: Symbol; msolist: Ignore;">·  THEY ARE LUMINESCENT AND EASILY SEEN AT NIGHT