Phylum Cnidaria

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Phylum Cnidaria

• Biology I Honors

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Examples

• Class Anthozoa
• The Coral and Sea Anemones
• Class Syphozoa
• The Jellyfish
• Class Hydrozoa
• The Hydra

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Habitat

• Fresh and Salt water

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Symmetry

• Radial

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Number of Tissue Layers

• Two
• Endoderm
• Inner layer
• Lines gut
• Ectoderm
• Outer layer

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Support/Skeletal

• None
• Jelly like layer in between ecto and endoderm
• Called mesoglea

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Muscular

• None
• Though cnidarians can weakly move tentacles or
  pulse their bodies
• Contraction of Ectodermal cells

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Digestion

• Incomplete Digestive system - Some organs
• Mouth
• Gut
• NO ANUS

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Respiration

• Diffusion

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Excretion

• Diffusion

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Circulation

• Diffusion

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Nervous

• Primitive Nerve tissue
• Nerve Net
• Causes pulsing motion seen in jelly fish

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Temperature Regulation

• Ectotermic

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Reproduction

• Sexual
• Release sperm and egg into water
• Asexual
• budding

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Miscellaneous

• Polyp form
• Attaches to a structure
• Tentacles point up
• Coral hydra
• Medusa form
• Floats
• Tentacles point down
• jellyfish

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Miscellaneous

• Stinging cells
• cnidocytes
• On tentacles
• Stun/paralyze prey
• Allow prey to be ingested

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Miscellaneous
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Miscellaneous