Phylum Cnidaria Greek sea nettles

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Phylum - CnidariaGreek sea nettles

• Jellies and Corals

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Jelly Bellies
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Basic Features

• Radially symmetrical
• 2 body forms sessile polyp or free-swimming
  medusa
• 2 tissue layer outer ectoderm inner endoderm
  with gelatin like mesoglea in middle
• Have a nervous system Nerve net
• Most live in marine environments
• 7,000 species

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Anatomy

• Tentacles surround a mouth/anus
• Nematocysts capsules with sticky or barbed
  tubes that can poison prey when activated by
  touch or chemicals
• Gastrovascular cavity or gut for prey digestion
• Ovaries with eggs testes with sperm
• Planula larva formed by egg sperm
• Bud an asexual reproduction form

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Nematocyst
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Nematocysts

• Function in defense, prey capture, attachment
  locomotion
• It takes 3 milliseconds to discharge, and the
  filament is pushed out at the velocity of 2
  meters per second, which corresponds to a
  velocity of 40,000 Gs, one of the fastest
  cellular processes in nature.

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Examples

• Class Hydrozoa Portuguese Man of War
• A colony
• Class Scyphozoa jellyfish
• Class Anthozoa reef building corals
• Polyps that secrete calcium carbonate
• Sea anemones
• Class Cubozoa box jellyfish of N. Australia
  powerful toxin has caused many deaths

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Class Hydrozoa - Hydra
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Class Hydrozoa
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Class Scyphozoa jelly fish
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Class Scyphozoa Fried egg jellyfish
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Class Schyphozoa moon jelly
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Other Facts

• Coral bleaching occurs when corals expel their
  colorful zooxanthellae protist symbioants that
  give corals O food.
• If stung remove tentacles with towel, wash with
  sea water, vinegar alcohol.
• This will inactivate nematocysts, urine may help
  if nothing else available.

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Other Facts

• Black, pink, red corals are used for jewelry
• Reef development fringing barrier atolls
• Some anemones can swim

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Class Anthozoa
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Sea Anemones

• They have a symbiotic relationship with clown
  fish. They share food and protect each other from
  predators. Clown fish also help to keep the sea
  anemones free from debris.

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Class Anthozoa - coral