radiate animals cnidarians and ctenophores. radiates are eumetazoans
TRANSCRIPT
Radiate Animals
Cnidarians and Ctenophores
Radiates Are Eumetazoans
PhylumC nidaria
H ydra , je lly fish e tc ...
Phy lumC tenophoraC om b je llies
G rade R ad ia taR adia l Sym etry
D iv is ion Protostom ia D iv is ion D euterostom ia
G rade B ila te ra taB ila te ra l Sym etry
Eum etazoaTrue T issues
Radiates
• Radial symmetry
• Tissue level organization
• Two germ layers– Ectoderm and endoderm
• Nerve net (simple nervous system)
• Extracellular digestion
Radiate Phyla
• Cnidaria • Ctenophore
Phylum Cnidaria
• Two forms– Polyp– Medusa
• Tentacles
• Nematocyst
Polyp and Medusa Forms
Class Hydrozoa
• Mostly colonial
• Polyp and medusa life cycle for most
• Hydra – non colonial polyp stage only
• Obelia – typical colony– Chiton exoskeleton– Extracellular and intercellular digestion
Hydra
Hydra Tissue Structure
Obelia Life Cycle
Gonionemus
Class Scyphozoa
• Larger jellyfish
• Not colonial
• No vellum
• Internal gastric pouches– Radial canals lead to ring canal
Aurelia Life Cycle
Medusa
Strobilia
Class Anthozoa
• Subclasses– Zoantharia – anemones, hard coral– Alcyonaria – sea fans (soft coral)– Ceriantipatheria – tube anemone, horny coral
• Polyp form, no medusa stage
• Partitioned gastrovascular cavity
Sea Anemone
Sea Anemone
Anemone Fish (Clown Fish)
Zoantharian Coral
• Calcium carbonate exoskeleton secreted externally from base
• Contain mutualistic zooxanthallae algae
• Live in colonies• Hexamerous symmetry
Coral Polyps
Alcyonarian Coral
• Octomerous symmetry
• Colonial
• Can communicate with members of colony through tubes call solenia
• Endoskeleton composed of spicules and protein and secreted within mesoglea
Soft Corals
Phylum Ctenophora
• Comb Jellies
• Move using cilia– Comb plates
• Do not have nematocysts– Colloblasts capture food
Comb Jelly Tentacle
Comb Jelly Structure
Comb Jelly Cilia
Predatory Comb Jellies Approaching Prey
Predatory Comb Jelly Engulfing a Comb Jelly
Comb Jelly After a Meal