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Cnidaria
Hydras, anemones, jellyfish, corals
Key Characteristics
 Lives both in salt and fresh water
 Simple nervous system’
 Stinging cells
 Radial Symmetry
 Two embryonic cell layers
Anatomy
 Nerve net- areas densely pact with nerve cells
 Statocyst- an organ for movement
 Ocelli- simply sensory organ
 Two-way digestion- food enters and leaves same cavity
 Hydrostatic Skeleton- muscle changes with liquid
Anatomy cont.
 Tentacle- surrounds mouth to aid food captures
 Nematocyst- Harpoon like stinging cells
 Mouth- takes in food and removes waste
 Gastrovascular cavity- distributes digested nutrients
 Bud- group of cells that grows into new organism
Digestion
 Two way Digestion
 Mouth also anus
 Gastrovascular cavity digests and distributes food

Waste pushed out mouth
 Tentacles aid in releasing waste
Respiration
 Breath through diffusion
 Oxygen obtained through water
 Diffuses oxygen higher to lower
concentration
 Diffuses in gastrovascular cavity
 Possible through thin cell layers
Internal Transport
 Gastrovascular cavity breaks down particles
 Cells surrounding cavity absorb
 Nutrients distributed by cells
 Thin cells create semipermeable body
 Unused particles leave through anus
Excretion
 Gaseous wastes eliminated by diffusion
 Dissolved wastes leave through diffusion
 Waste created in gastrovascular cavity
 Undissolved waste leaves through anus
 Waste is taken in and leaves through mouth
Response
 Nematocyst defends animal
 Nerve nets aid in response
 Ocelli
 Does not have brain or eyes
 Nematocyst located all over
Movement
 Hydrostatic skeleton
 Moves with muscle contractions
 Shape changes depending on fluid
 Without liquids there is no movement
 Expelling liquids propels movement
Reproduction
 Both asexual and sexual reproduction
 Budding creates genetic clone
 Sperm and eggs are released in water
 Combined in water create zygote
 Zygote settles and grows into adult polyp
Examples
 Cubozoa- box jellyfish
 Scyphozoa- moon and purple jellyfish
 Anthozoa- anemone, coral
 Hydrozoa- hydra, Portuguese man of war
 Divided into fresh and salt water groups
Facts
 10,000 different species
 130 species in Sydney Harbor
 Only two are dangerous to humans
 Comes from Greek cnidos or stinging nettle
 Have no developed organs
Works Cited
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http://classconnection.s3.amazonaws.com/556/flashcards/1811556/gif/cnidaria_hydra1365168401629.gif
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http://library.thinkquest.org/28751/review/animals/2.html
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http://www.vattenkikaren.gu.se/fakta/arter/cnidaria/overcnid/nass04e.html
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http://www.ncbi.nlm.nih.gov/pubmed/7833621
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https://www.boundless.com/biology/the-musculoskeletal-system/types-of-skeletal-systems/hydrostatic-skeleton-exoskeletonand-endoskeleton/
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http://www.angelfire.com/mo2/animals1/phylum/jellyfish.html
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http://science.kennesaw.edu/~jdirnber/Bio2108/Lecture/LecBiodiversity/33_Labeled_Images/33_06HydraCnidocyte-L.jpg
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http://upload.wikimedia.org/wikipedia/commons/3/32/Marrus_orthocanna_crop.jpg
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https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRAIwYYk21MD6R0MTzEXMwq2mdbzM18Af9Dc6sxswrWOb1mODMsQ
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http://cnidarianh.blogspot.com/2007/02/feeding-respiration-excretion.html
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http://w3.shorecrest.org/~Lisa_Peck/MarineBio/syllabus/ch7invertebrates/Invertwp/invert_wp_05/cnidaria/miles1/Cool.htm
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http://www.mesa.edu.au/cnidaria/images/jelly_life-cycle.jpg
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https://lh4.googleusercontent.com/-nv2CohpE238/TYumw6y9wHI/AAAAAAAAJ-A/X-wIl_VNczQ/s1600/Picture%2B14.png
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http://ichef.bbci.co.uk/naturelibrary/images/ic/credit/640x395/c/cn/cnidaria/cnidaria_1.jpg