CnidariaCnidaria

General CharacteristicsGeneral Characteristics The name Cnidaria comes from the Greek word "cnidos," The name Cnidaria comes from the Greek word "cnidos,"

which means stinging nettlewhich means stinging nettle They have stinging cells called nematocystsThey have stinging cells called nematocysts

An exclusively aquatic phylumAn exclusively aquatic phylum Tissue level organizationTissue level organization

Generally, their bodies are two cell layers thickGenerally, their bodies are two cell layers thick Radial symmetry; Little specialization; PseudocoelomateRadial symmetry; Little specialization; Pseudocoelomate Extracellular digestionExtracellular digestion Hydrostatic skeletonHydrostatic skeleton Both asexual and sexual reproductionBoth asexual and sexual reproduction External fertilizationExternal fertilization One opening, the mouthOne opening, the mouth

http://fotokudra.lt/files/I261542.jpg

http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Cnidaria/Class-Hydrozoa/HydroidPolyps/Obelia_dichotoma.html

http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg3_files/hydra3.jpg

Class Hydrozoa Class Hydrozoa (Hydroids)(Hydroids)

Hydra Obelia

http://www.biology.iastate.edu/Courses/211L/Cnidar/%20CnidINDX.htm

Goneonemus

http://seanet.stanford.edu/HydroScyphozoa/aurelia_lab580.jpg

Class Scyphozoa Class Scyphozoa (Jellyfish)(Jellyfish)

Aurelia

http://www.valdosta.edu/~jlgoble/Sea%20Anemone%20Diadumene%20Dia%2030cm%201.JPG

Class Anthozoa Class Anthozoa (Corals & Sea (Corals & Sea Anemone)Anemone)

Sea Anemone

Class Cubomedusa Class Cubomedusa (Box (Box Jellyfish)Jellyfish)

http://thestashbox.files.wordpress.com/2009/02/226boxjellyfish1.jpg

Box Jelly

Body Plan Body Plan Tissue level of organizationTissue level of organization

Outer covering (epidermis), inner gasterodermis, non-cellular Outer covering (epidermis), inner gasterodermis, non-cellular mesoglea between the two; Diploblastic, body and tentacles mesoglea between the two; Diploblastic, body and tentacles consists of two cell layersconsists of two cell layers

Possess stinging structures, nematocysts, housed in Possess stinging structures, nematocysts, housed in cells called cnidocytes; Single body opening, the mouthcells called cnidocytes; Single body opening, the mouth

Radial symmetry Radial symmetry Two body formsTwo body forms

Polyp: cylindrical with tentacles at one end; Sessile (non-motile) Polyp: cylindrical with tentacles at one end; Sessile (non-motile) but some capable of locomotion; mouth points upward; EX: The but some capable of locomotion; mouth points upward; EX: The HydraHydra

Medusa: Free swimming; Bell shaped; Swim by undulations of their Medusa: Free swimming; Bell shaped; Swim by undulations of their bell; Thicker mesoglea mouth-side down; EX: The Jellyfishbell; Thicker mesoglea mouth-side down; EX: The Jellyfish

Some cnidarians exist only in polypoid or medusoid Some cnidarians exist only in polypoid or medusoid form, others alternate between the two form, others alternate between the two Both diploid so not true alternation of generationsBoth diploid so not true alternation of generations

Body Plan cont.Body Plan cont.

http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg

http://www.arcodiv.org/cnidarians.html

FeedingFeeding Carnivorous or filter feedersCarnivorous or filter feeders Medusa do not hunt for prey, use “sit-and-trap” methodMedusa do not hunt for prey, use “sit-and-trap” method

Uses cnidae and toxins to stun and kill preyUses cnidae and toxins to stun and kill prey Sessile ployps depend on organisms that come in Sessile ployps depend on organisms that come in

contact with tentaclescontact with tentacles Tentacles have stinging cells (cnidocytes) that contain small Tentacles have stinging cells (cnidocytes) that contain small

harpoons called nematocystsharpoons called nematocysts Harpoon propelled by osmotic pressure, spears prey and draws it Harpoon propelled by osmotic pressure, spears prey and draws it

back to hydraback to hydra Both have a ring of tentacles around the mouthBoth have a ring of tentacles around the mouth Extracellular digestion; gut cavity for digestion, lining Extracellular digestion; gut cavity for digestion, lining

cells engulf food by phagocytosiscells engulf food by phagocytosis Enzymes secreted from the gastrodermis break down the foodEnzymes secreted from the gastrodermis break down the food

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RespirationRespiration Contains no respiratory systemContains no respiratory system

This image depicts the This image depicts the internal structure of a internal structure of a jellyfish (a Medusae jellyfish (a Medusae cnidaria). Because the great cnidaria). Because the great majority of cells are directly majority of cells are directly in contact with the ocean in contact with the ocean water, a complicated water, a complicated respiratory system is not respiratory system is not

needed.needed.

http://www.arcodiv.org/cnidarians.html

CirculationCirculation No circulatory system (blood vessels)No circulatory system (blood vessels) Majority of cells come in direct contact of seawaterMajority of cells come in direct contact of seawater Have gastrovascular cavity; inner cells exposed to waterHave gastrovascular cavity; inner cells exposed to water

Only two cell layers thick, all cells exposed to water for nutrient Only two cell layers thick, all cells exposed to water for nutrient and gas exchangeand gas exchange

http://www.connecticutvalleybiological.com/images/vc1336v.jpg

http://www.arcodiv.org/cnidarians.html

ExcretionExcretion Contains no excretory organsContains no excretory organs Gastrovascular cavity serves for gas exchange and Gastrovascular cavity serves for gas exchange and

digestiondigestion Gas exchange takes place directly across the surface of their body Gas exchange takes place directly across the surface of their body

and waste is released either through their gastrovascular cavity or and waste is released either through their gastrovascular cavity or by diffusion through their skin by diffusion through their skin

No anusNo anus Excretes through mouth, only openingExcretes through mouth, only opening

ResponseResponse Simple net like nervous systemSimple net like nervous system

Coordinates contraction of muscles; Little central controlCoordinates contraction of muscles; Little central control

http://www.arcodiv.org/cnidarians.html

http://www.aboutmyplanet.com/files/2008/12/800px-Jellyfish_in_the_Montery_Bay_Aquarium-resized.jpg

MovementMovement Polyp Polyp

Sits on basal disk, used to glide around with help of mucus Sits on basal disk, used to glide around with help of mucus secretionssecretions

Some can somersault, bending over and attaching itself to Some can somersault, bending over and attaching itself to substrate by its tentacles and looping over to new locationsubstrate by its tentacles and looping over to new location

If polyp detaches itself from substrate, it can float to If polyp detaches itself from substrate, it can float to surfacesurface

Medusae Medusae Outer layer, epithelium, contains specialized Outer layer, epithelium, contains specialized

epitheliomuscular cells, each can contract individuallyepitheliomuscular cells, each can contract individually These cells form muscular rings around the bell shape of These cells form muscular rings around the bell shape of

the jellyfish; allows the animal to propel through waterthe jellyfish; allows the animal to propel through water

ReproductionReproduction Polyps reproduce asexually (budding and fragmentation)Polyps reproduce asexually (budding and fragmentation) Medusae reproduce sexuallyMedusae reproduce sexually Fertilization externalFertilization external Alternation between medusa, sexually reproductive Alternation between medusa, sexually reproductive

stage, and polyp, the asexual stage stage, and polyp, the asexual stage Class Anthozoa has no medusa stageClass Anthozoa has no medusa stage

Medusae has a distinct larval stage which is planktonic; Medusae has a distinct larval stage which is planktonic; called planulae; multicellular, pear-shaped, entirely called planulae; multicellular, pear-shaped, entirely ciliatedciliated Jellyfish have separate male and femalesJellyfish have separate male and females Medusae stage is dominantMedusae stage is dominant Some exhibit the medusa form throughout their life while others first Some exhibit the medusa form throughout their life while others first

pass through other phases before maturing into the medusa form pass through other phases before maturing into the medusa form

ReproductionReproduction

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Works CitedWorks Cited "Introduction to Cnidaria." "Introduction to Cnidaria." UCMP - University of California Museum of PaleontologyUCMP - University of California Museum of Paleontology. Web. 15 . Web. 15

Apr. 2010. <http://www.ucmp.berkeley.edu/cnidaria/cnidaria.html>.Apr. 2010. <http://www.ucmp.berkeley.edu/cnidaria/cnidaria.html>. "Cnidarians." "Cnidarians." W. Fielding Rubel School of Business: Bellarmine UniversityW. Fielding Rubel School of Business: Bellarmine University. Web. 16 Apr. 2010. . Web. 16 Apr. 2010.

<http://cas.bellarmine.edu/tietjen/images/cnidarians.htm>.<http://cas.bellarmine.edu/tietjen/images/cnidarians.htm>. "The Anemones, Corals and Jellyfish (Phylum Cnidaria)." "The Anemones, Corals and Jellyfish (Phylum Cnidaria)." The Earth Life WebThe Earth Life Web. Web. 19 Apr. . Web. 19 Apr.

2010. <http://www.earthlife.net/inverts/cnidaria.html>.2010. <http://www.earthlife.net/inverts/cnidaria.html>. Klappenbach, Laura. "Diet - Cnidarian Diet and Eating Habits." Klappenbach, Laura. "Diet - Cnidarian Diet and Eating Habits." Animals Wildlife - Animal Facts, Animals Wildlife - Animal Facts,

Animal Pictures, Habitat Facts, Evolution and ZoologyAnimal Pictures, Habitat Facts, Evolution and Zoology. Web. 20 Apr. 2010. . Web. 20 Apr. 2010. <http://animals.about.com/od/cnidarians/ss/cnidarians_6.htm>.<http://animals.about.com/od/cnidarians/ss/cnidarians_6.htm>.

"The Noncoelomate Animals." "The Noncoelomate Animals." BiologyBiology. Sixth ed. Boston: McGraw Hill, 2002. 886-89. Print.. Sixth ed. Boston: McGraw Hill, 2002. 886-89. Print.

Works Cited (Pictures)Works Cited (Pictures) "Multi-cell Organisms." "Multi-cell Organisms." A Review of the UniverseA Review of the Universe. Web. 16 Apr. 2010. <http://universe-. Web. 16 Apr. 2010. <http://universe-

review.ca/F10-multicell.htm#Index>.review.ca/F10-multicell.htm#Index>. "Simple Animals." Web. 19 Apr. 2010. "Simple Animals." Web. 19 Apr. 2010.

<http://biology.unm.edu/ccouncil/Biology_203/Summaries/SimpleAnimals.htm>.<http://biology.unm.edu/ccouncil/Biology_203/Summaries/SimpleAnimals.htm>. "New Page 1." "New Page 1." Virtual Microscope Home PageVirtual Microscope Home Page. Web. 19 Apr. 2010. . Web. 19 Apr. 2010.

<http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg3.htm>.<http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg3.htm>. "Obelia Dichotoma." "Obelia Dichotoma." WWU: On CampusWWU: On Campus. Web. 19 Apr. 2010. . Web. 19 Apr. 2010.

<http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Cnidaria/Class-<http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Cnidaria/Class-Hydrozoa/HydroidPolyps/Obelia_dichotoma.html>.Hydrozoa/HydroidPolyps/Obelia_dichotoma.html>.

"Gonionemus." "Gonionemus." Biology Program at ISUBiology Program at ISU. Web. 19 Apr. 2010. . Web. 19 Apr. 2010. <http://www.biology.iastate.edu/Courses/211L/Cnidar/%20CnidINDX.htm>.<http://www.biology.iastate.edu/Courses/211L/Cnidar/%20CnidINDX.htm>.

"Hydrozoa & Scyphozoa." "Hydrozoa & Scyphozoa." SeaNetSeaNet. Web. 19 Apr. 2010. . Web. 19 Apr. 2010. <http://seanet.stanford.edu/HydroScyphozoa/index.html>.<http://seanet.stanford.edu/HydroScyphozoa/index.html>.

"Search Results | SpongeBob.com." "Search Results | SpongeBob.com." SpongeBob.com | SpongeBob SquarePants Episodes, SpongeBob.com | SpongeBob SquarePants Episodes, Games, & PicturesGames, & Pictures. Web. 20 Apr. 2010. <http://spongebob.nick.com/search/game/spongebob. Web. 20 Apr. 2010. <http://spongebob.nick.com/search/game/spongebob%20games/0>.%20games/0>.

"Anemone." "Anemone." Valdosta State UniversityValdosta State University. Web. 19 Apr. 2010. . Web. 19 Apr. 2010. <http://www.valdosta.edu/~jlgoble/topic.html>.<http://www.valdosta.edu/~jlgoble/topic.html>.

"Foto KÅ«dra - Fotografija - Cnidaria Scyphozoa II." "Foto KÅ«dra - Fotografija - Cnidaria Scyphozoa II." FotoKÅ«dra - Fotografija | KÅ«ryba | FotoKÅ«dra - Fotografija | KÅ«ryba | BendravimasBendravimas. Web. 20 Apr. 2010. <http://fotokudra.lt/img.php?. Web. 20 Apr. 2010. <http://fotokudra.lt/img.php?img=182032&nav=cat&page=156>.img=182032&nav=cat&page=156>.

"Jellyfish Take Over Ocean: A Dangerous Warning Sign." "Jellyfish Take Over Ocean: A Dangerous Warning Sign." Go GreenGo Green. Web. 20 Apr. 2010. . Web. 20 Apr. 2010. <http://www.aboutmyplanet.com/green-news/jellyfish-ocean/>.<http://www.aboutmyplanet.com/green-news/jellyfish-ocean/>.

Hopcroft, Russ. "Cnidarians - Jellyfish and Kin." Hopcroft, Russ. "Cnidarians - Jellyfish and Kin." Arctic Ocean DiversityArctic Ocean Diversity. Census of Marine Life, 4 . Census of Marine Life, 4 Jan. 2008. Web. 20 Apr. 2010. <http://www.arcodiv.org/cnidarians.html>Jan. 2008. Web. 20 Apr. 2010. <http://www.arcodiv.org/cnidarians.html>