Mollusks

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Mollusks
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Phylogeny
Platyhelminthes
Porifera
Mollusca
Chordata
Arthropoda
Annelida
Cnideria
Nematoda
Echinodermata
pseudocoelom
segmentation
acoelom
Protostome schizocoelem
Deuterostomes eucoelom
radial symmetry
bilateral symmetry
true tissue
no true tissues
Ancestral Protist
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Phylum Mollusca
Class Polyplacophora
Class Gastropoda
Class Bivalvia
Class Cephalopoda
chitons
Snails Sea slugs nudibranchs
Squid Octopus Cuttlefish Nautilus
clams
More than 500,000 known species
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Body Plan

• Three main parts
• Muscular foot- for movement
• Visceral mass- contains most of the internal
  organs
• Mantle cavity- houses gills

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Generalized Mollusc Anatomy
mantle
visceral mass
foot
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Feeding Types

• Grazers (radula- scraping tongue)
• Filter feeding
• Egg eaters
• Active predation

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Kingdom Animalia Phylum Mollusca
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Class Polyplacophora chiton

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Class Gastropoda Subclass Opisthobranchia
Spanish Dancer (nudibranch) egg mass
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nudibranchsPhistella
Phylum Mollusca Class Gastropoda
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nudibranchs
Nembrotha kubaryana
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nudibranchs
Chromodoris annae
Halgerda batangas
Cuthona sp.
Chromodoris
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Class Gastropoda
periwinkle
Opihi
Cowery
Cone snail
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Epitomium
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Tritons trumpet
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pterapods
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Class Bivalvia
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oyster
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Class Cephalopoda
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Class Cephalopoda
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Class Cephalopoda
http//www.youtube.com/watch?vU2s3C0lkQE0
http//www.youtube.com/watch?vNR53smpV_xg
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Class Cephalopoda
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Octopus Intelligence
http//www.youtube.com/watch?vGQwJXvlTWDw
Start at 2 minutes
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Mimic octopus from Indonesia
flatfish
Sea snake
lionfish
http//www.youtube.com/watch?vH8oQBYw6xxc
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Blue-ringed octopus
Highly venomous