Transcript Radiate Animals - Dr. M. Belanich / FrontPage

Radiate Animals
Cnidarians and Ctenophores
Radiates Are Eumetazoans
Eumetazoa
True Tissues
Grade Radiata
Radial Symetry
Phylum
Cnidaria
Hydra, jellyfish etc...
Phylum
Ctenophora
Comb jellies
Grade Bilaterata
Bilateral Symetry
Division Protostomia
Division Deuterostomia
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
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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
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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