Intro

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Intro
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P. Cnidaria C. Scyphozoa

• Characteristics
• jellyfish/cup animals, clear/mulitcolored
• bell 2 cm ? 2 m diameter
• tentacles 5 cm ? 70 m
• marine, 3000 m deep
• drift or pulse
• bell-shaped, lack velum
• scalloped margin w/ notchs bearing pairs
  of lappets
• btwn lappets is rhopalium
• rhopalium sense organ w/ statocyst/ocelli
• nerve nets controls pulsations/reactions

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P. Cnidaria C. Scyphozoa

• Nutrition
• nematocysts in tentacles/manubrium/body surface
• prey stung and moved to mouth lobes
• Aurelia feeds on phytoplankton caught in mucus
• mouth on underside leads to stomach
• manubrium w/ 4 frilly oral arms
• 4 gastric pouches extend from stomach
• gastrodermis extends into
  gastric
  filaments w/ nematocysts
• no gastric filaments in
  hydromedusae
• radial canals connect gastric
  pouches to ring
  canal in margin

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P. Cnidaria C. Scyphozoa

• Life cycle and reproduction
• dioecious
• gonads in gastric pouches
• internal fertilization
• zygotes develop in water or w/i oral
  canals of ?
• planula larva attaches to substrate/develops into
  scyphistoma (hydra-like)
• scyphistoma forms buds (strobiliation)
• buds break off forming ephyra
• ephyra develops into jellyfish
• variations lacking either stage

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P. Cnidaria C. Cubozoa

• Dominant medusae, inconspicuous polypoid
• 2 ? 25 cm squarish bell
• tentacles at corners
• base of tentacles flattened into pedalium
• have rhopalia
• non-scalloped margin
• velarium inward edge
• facilitates swimming
• good swimmers
• great predators
• kill humans, eat fish
• no ephyra
• direct metamorphosis from polyp to medusa

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P. Cnidaria C. Anthozoa

• Characteristics
• flower animals
• no medusa stage
• marine, tropical ? polar
• solitary/colonial
• hydrostatic skeletons, some w/ skeletons
• large, divided gastrovascular cavity
• 3 subclasses
• Hexacorallia (sea anemones/hard corals)
• hexamerous body plan
• Ceriantipatharia (tube anemones/thorny corals)
• Octocorallia (soft or horny corals/sea fans/sea
  pen or pansies)
• octomerous body plan

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P. Cnidaria P. Anthozoa

• Sea anemone (SC. Hexacorallia)
• 5 ? 200 mm long, carnivorous
• pedal discs attach to substrate, some bury in
  mud/sand
• move via pedal discs, limited swimming
• tentacles surround oral disc which leads to
  pharynx
• ciliated siphonoglyph produces water current
• gastrovascular cavity
  radially
  divided by
  septa into 6
  chambers
• well-developed muscles
• some mutualistic
• monoecious/dioecious
• asexual repro. via pedal
  laceration/fission/budding

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P. Cnidaria C. Anthozoa

• Stony/true corals (SC. Hexacorallia)
• secrete calcareous cups
• withdraw for protection

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P. Cnidaria C. Anthozoa

• Coral reefs
• ?? productivity/diversity
• CaCO3 formations built by reef-building
  (hermatypic) corals
• symbiotic relationship w/ dinoflagellates
• require warmth, light, salinity (btwn 30 N and
  30 S)

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P. Cnidaria C. Anthozoa

• fringing reef near landmass w/ small/no lagoon
  btwn reef/shore
• barrier reef run parallel to shore w/ large
  lagoon btwn reef/shore
• atolls encircle lagoon
• each w/ characteristic community
• reef front (fore reef slope) faces sea
• reef crest top of reef
• reef flat slopes to lagoon
• threats
• ? nutrients
• overfishing
• pesticides
• sediment
• coral bleaching expel zooxanthellae

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Comparison Btwn Cnidaria and Ctenophora

• Similarities
• radial symmetry, oral/aboral axis
• gelatinous ectomesoderm, no coelom, nerve net
• tissue level organization
• Differences (Ctenophores have)
• lack nematocysts, have comb plates and
  colloblasts
• muscle cells in mesenchyme
• no di-/polymorphism, not colonial
• pharynx, anal openings
• triploblastic?
• mosaic (determinate) cleavage

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P. Ctenophora

• Characteristics
• 100 sp. (comb jellies, sea walnuts)
• marine, warm water
• 8 radial rows of comb plates for swimming
• biradial symmetry
• tissue level organization
• transparent, bioluminescence
• no polymorphism/dimorphism

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P. Ctenophora

• mostly free-swimming via comb plates, others
  sessile/creeping
• comb rows 8 bands extending btwn oral/aboral
  poles
• comb plates plate of fused cilia arranged in
  rows
• can move backward or forward
• 2 long, solid tentacles
• have colloblasts for adhesion and
  catching prey

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P. Ctenophora

• epidermis (ectoderm), gastrodermis (endoderm),
  gelatinous collenchyme
  (mesoglea) btwn
• muscle fibers and ameboid cells in mesoglea
• triploblastic?
• respiration and excretion through body surface
• feeding and digestion
• mouth/pharynx/stomach/aboral and anal canals
• anal pores
• have colloblasts for adhesion/catching prey
• eat copepods
• lack nematocysts
• some obtain from cnidarians

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P. Ctenophora

• nervous and sensory systems
• subepidermal plexus concentrated under comb
  plates
• statocyst near anal pore
• sensory cells
• reproduction and development
• monoecious
• gonads in gastrovascular canals under
  comb plates
• mosaic (determinate) cleavage
• free-swimming cydippid larva