Phyla Cnidaria and Ctenophora= jellies, anemones, corals, hydrozoans and comb jellies

= Coelenterates

Fantasy vs Reality

Coelenterate CharacteristicsRadial/biradial symmetry

Diploblastic

Majority marine

Benthic or planktonic

Solitary or colonial

Free swimming larvae

Cnidarian Body PlanEpidermis, gastrodermis& mesogleaPolymorphismPolypCylindrical, pedal disk orphysa, terminal mouthDactylo-, gono-, gastro-,siphonozooidsMedusaExumbrella, subumbrellaMarginal tentaclesManubriumReproductive stageMuscular system = notmesodermalNerve system = 2 nervenets

Cnidaria Body:Sensory/Defense Organs

Mechanoreceptors = hairlike, in area of cnidocytesRhopalia = variety of structuresStatocystsOcelli = pigment cup and eyes = in cubozoans, bell margin

Nematocysts in cnidocytes, damaging

Ctenophore Body Plan

Spherical to ovoid, intricate canal systemMouth at one pole, apical sense organ at the otherCtene rows extending from mouth to ASO = paddle like combPlates of fused ciliaEpidermis and gastrodermis separated by mesogleaSticky lasso cells (colloblasts), no nematocyst

mouthdigestivecavity

canal

canal

canal

canalcanal

canal

canalcanal

canal

canal

canal

canaltentacle tentacle

canal

Nutrition and Digestive System

http://www.youtube.com/watch?v=HheMqLyw1d8&feature=related

CarnivorousTrap prey or suspension feeders,nematocystsContractile tentacles,colloblasts

Symbiotic algae(particularly corals)

Digestion= extra- and intracellular

One digestive opening only, analpores

Waste diffusion and rosettes

Reproduction and LifecyclesSexualDioeciousHermaphroditicPlanula orcydippid

Strobilation

Asexuala. Buddingb. fissionc. Frustuled. Segmentation

Symbiosis and Interactions

1. Anemones and hermit crabs2. Nudibranchs3. Clownfish and anemone4. Zooxanthellae

Classification CnidariaAnthozoa Staurozoa Cubozoa Scyphozoa Hydrozoa

Polyp/medusaNo statocyst/rhopalia

True jelliesPolyp/medusa

Rhopalia

SmallEyes

Rhopalia

PolypMuscles

Medusa

Ctenophore ClassificationClass TentaculataOvoid bodiesContain tentacles

Class NudaConical bodiesNo feeding appendagesLarge pharynx with largecilia= create feeding currents

Fun FactsCnidaria = Greek “cnidos” = stinging,nettleCan contain more than 800 tentaclesJelly fish = >95% waterCoral reefs = economic importanceUsed for bone replacement

Prey on small fish = problem inaquaculture= Mnemiopsis= invasive species in BalticBioluminescence