Presentation on theme: "PHYLUM MOLLUSCA. Phylum characteristics More species of mollusca than any other group in the ocean, 110,000 living species. Bilateral symmetry Complete."— Presentation transcript:
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.
CLASSES Bivalve Gastropoda Cephalopoda
Class Bivalve EX. Clams, oysters, mussels, scallops 2 shells joined by a ligament Anterior & Posterior adductor muscles Filter feeders Lack Radula
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
Who are they? (conch, abalone, murex, cowrie, cones)
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