1. PHYLUM MOLLUSCA

2. Phylum characteristics
More species of mollusca than any other group in the ocean, 110,000 living species.
Bilateral symmetry
Complete digestive tract.
Respiration may be surface exchange, gills or lungs.
Nervous system is cephalized; ganglia
Soft body protected by a calcium carbonate shell which is secreted by a mantle.

3. CLASSES
Bivalve
Gastropoda
Cephalopoda

4. Class Bivalve EX. Clams, oysters, mussels, scallops
2 shells joined by a ligament
Anterior & Posterior adductor muscles
Filter feeders
Lack Radula

6. Class Gastropoda Largest group of mollusca Torsion
Larvae start as bilateral but because of torsion become asymmetric.
Many have an operculum
Ganglion and eyes
Dioecious or hermaphroditic. Sperm-darts

7. Who are they? (conch, abalone, murex, cowrie, cones)

8. Class Cephalopoda ‘Head-foot’ Most complex brain of all invertebrates.
90+ tentacles
Beak inside buccal cavity
May have internal shell or lack shell entirely. Only 1 in this class has an exterior shell.
Chromatophores

10. SQUID Dissection