The Characteristics of Phylum Cnidaria

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The Characteristics of Phylum Cnidaria
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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

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Radial Symmetry
oral
aboral
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Bilateral Symmetry
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Blind Sac Gut
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Complete Gut
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Diploblastic
gut
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Diploblastic
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Triploblastic
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Polyp and Medusa Body Forms
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POLYP ANATOMY
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Medusa Body Form
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Nematocysts
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Nematocyst
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Nematocysts
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Nerve Net
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Diffusion Across the Body Wall
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Sea Anemones
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Circulation in a Moon Jellyfish
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The Cnidarian Life Cycle
The Cnidarian Life Cycle
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Coloniality
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Polymorphism
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Polymorphism