the characteristics of phylum cnidaria
DESCRIPTION
The Characteristics of Phylum Cnidaria. Phylum Cnidaria. Class Anthozoa. Class Hydrozoa. Class Scyphozoa. Class Cubozoa. Corals Anemones. Hydra Portuguese Man-Of-War Stinging Limu Fire Coral. True jellyfish. Box jellies Sea wasps. Characteristics of Phylum Cnidaria. - PowerPoint PPT PresentationTRANSCRIPT
The Characteristics of Phylum Cnidaria
Phylum CnidariaPhylum Cnidaria
Class Anthozoa
Class Hydrozoa
Class Scyphozoa
Class Cubozoa
CoralsAnemones
HydraPortuguese Man-Of-War
Stinging LimuFire Coral
True jellyfish Box jelliesSea wasps
Characteristics of Phylum Cnidaria
• radial symmetry• blind sac gut (= coelenteron or gastrovascular cavity)• diploblastic with mesoglea• polyp and medusa body forms• nematocysts (= specialized stinging capsules)• nerve net• lack excretory, circulatory & respiratory systems• complex life cycle• many colonial forms exhibiting polymorphism
Radial Radial SymmetrySymmetry
aboral
oral
Polyp
Radial SymmetryRadial SymmetryJellyfishJellyfish
Phylum CnidariaPhylum Cnidaria
Medusa
Blind Sac GutBlind Sac Gut
Diploblastic- two germ layersDiploblastic- two germ layersPhylum CnidariaPhylum Cnidaria
NematocystsNematocysts
Nematocyst PictureNematocyst Picture
Nematocyst
More NematocystsMore Nematocysts
http://www.youtube.com/watch?NR=1&v=-Tp38DUjUnM&feature=endscreen
Nerve NetNerve Net
Diffusion Across the Body WallDiffusion Across the Body Wall
Sea AnemonesSea Anemones
Circulation in a Circulation in a Moon JellyfishMoon Jellyfish
The Cnidarian Life CycleThe Cnidarian Life Cycle
The Cnidarian Life Cycle
ColonialityColonialityCoral
Phylum Cnidaria
• polyps and medusa stage, although polyp stage is dominant.
• gut cavity of polyp is simple, lacking a pharynx and not divided by mesenteries.
• tetramerous (four-part) radial symmetry.
• gonads are ectodermal (found in the epidermis).
• medusa stage may possess specialized balance organs called statocysts and photosensitive organs called ocelli.
• solitary or colonials; some colonial forms highly polymorphic.
• includes hydroids (“stinging limu”), fire coral, pink coral, and siphonophores.
Class Hydrozoa(Gr. hydra, water serpent)
The Cnidarian Life CycleThe Cnidarian Life Cycle
The Hydrozoan Life Cycle
Hydrozoan Colony
Hydrozoan Colonies“Stinging Limu”
Hydrozoan Medusa
Hydrozoan Medusa
Hydrocorals
Fire CoralFire Coral
By-the-Wind-SailorA Floating Colony of Polyps
Coloniality and Polymorphism
Poly,orphism in the Poly,orphism in the Portuguese Man- of-WarPortuguese Man- of-War
• medusae stage dominate.
• polyp stage (scyphistoma) goes through strobilization to produce young medusa.
• bell margin lacks a velum.
• tetramerous (= four-part) radial symmetry.
• gut divided into a complex system of radial canals.
• some with a simple single mouth, but many with thousands of microscopic “mouths” at the ends of oral arms.
• gonads endodermal (found in the gastrodermis).
• specialized sense organs called rhopalia with ocelli & statocysts .
• includes some 200 marine species.
• "true" sea jellies.
Class Scyphozoa(Gr. skyphos, cup)
Moon Jelly Moon Jelly AnatomyAnatomy
Scyphozoan Life Cycle
strobilascyphistoma
Sea Jellies
• medusae dominate stage.
• polyp stage develops directly into medusa.
• bell margin with a velarium.
• tetramerous (= four-part) radial symmetry; bell cube-shaped with tentacles arising from each corner.
• gonads endodermal (found in the gastrodermis).
• specialized sense organs called rhopalia with ocelli & statocysts .
• includes some 15 marine species.
• includes box jellies and sea wasps.
Class Cubozoa(Gr. kybos, a cube)
Box Jellies
Seawasp
Box Jelly Anatomy
• Polyp stage only
• Blind sac gut
• mesenteries radiate inwards from the body wall
• gonads endodermal, borne on the mesenteries
• hexamerous (6-part) or octamerous (8-part) radial symmetry or biradial
• sea anemones, “true” stony corals, sea fans, sea pens, organ pipe coral, precious black coral, & zoanthids
(Gr. anthos, flower)Class Anthozoa
Subclass ZoanthariaOrder ActinariaSea Anemones
Sea Anemone Anatomy
Subclass HexacoralliaOrder Zoanthidae
• No hard skeleton• May be tough and leathery• Shallow water forms• Encrusting forms• Some with zooxanthellae• Polyp stage only
Subclass HexacoralliaOrder Antipatheria
Black Coral & Wire Coral
Wire coral
Black coral
Subclass HexacoralliaOrder Scleractinia
“True” Stony CoralsHermatypic- reef building, zooxanthellaeCommon species:
• Acroporidae- table• Acroporidea- rice • Agariciidae- flat lobe, corrugated• Faviidae- crust, ocellated• Fungiidae- humpback, mushroom• Pocilloporidae- lace, antler, cauliflower• Poritidae- finger, lobe, plate
“True” Stony Coralslobe
finger
mushroom
Porites rus
Octocorals
Sea pen
Organ pipe coral