(2) Protostome

(2) Protostome - Protostomes Molluscs Arthropods Cleavage...

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Protostomes Protostomes Molluscs Arthropods Annelids Cleavage is Spiral and Determinate Mouth developes at or near Blastopore, Anus developes elsewhere Eucoelomate - Schizocoely
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Phylum Mollusca Phylum Mollusca Have three-part body plan Visceral Mass - Contains internal organs Mantle - May secrete shell and/or contribute to development of gills or lungs Head-Foot - Muscle adapted for locomotion, attachment, or food capture, sensory reception Nervous system consists of several ganglia connected by nerve cords Coelom is reduced, and largely limited to the region around the heart Heart pumps hemolymph through vessels into hemocoel radula
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Life History Life History Shell Shell Layers Periostracum - conchiolin Prismatic - CaCO 3 Nacreous - CaCO 3 over protein
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Bivalves - Bivalves - Clams, Oysters, Mussels, and Scallops Beating of cilia causes water to enter cavity Filter Feeders capture tiny food particles suspended in water Shell of two hinged parts, closed by powerful muscles No head, no radula Circulatory system open Sexes are separate Ciliated gills hang down within mantle cavity on either side of visceral mass
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Have elongated, flattened foot Well-developed head region Eyes and tentacles project from coiled shell Gills are found in mantle cavity in aquatic gastropods Mantle functions as lung in terrestrial gastropods Gastropods - Gastropods - Snails, Slugs, Nudibranchs, Limpets
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Torsion Torsion Pretorsion Post-torsion
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(2) Protostome - Protostomes Molluscs Arthropods Cleavage...

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