Cnidarians

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Cnidarians

• Jellyfish, Sea anemones and Coral

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• Cnidarians are soft-bodied, carnivorous animals
  that have stinging tentacles arranged in circles
  around their mouths.
• Nematocyst poison filled stinging structure
  that contains a tightly coiled dart.

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Body Plans

• Cnidarians show radial symmetry
• 2 very different looking life stages

Polyp sea anemone Medusa - Jellyfish
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Life Processes

• Feeding carnivores, use nematocysts to
  capture.gastrovascular cavity digestion
  chamber with one opening.
• Respiration/circulation/excretion diffusion
• Response nerve net loosely organized network
  of nerve cells.
• Movement
• Polyps move by hydrostatic skeleton.
• Medusa move by jet propulsion.

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Asexual Reproduction

• Asexual Budding Swelling on polyp which falls
  off and produces more polyps.

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Sexual Reproduction

• Sexual External fertilization separate sexes
  egg/sperm produce a larvae which turns into a
  polyp and the buds release medusa.

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Types of Cnidarians
2. Hydra a colony of separate organisms.

• 1. Jellyfish largest is 4-6 meters

Ex. Portuguese man-of-war tentacles can be 164
feet long
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Types of Cnidarians

• 3. Sea anemones and Coral