Phylum Mollusca Gastropods Snails slugs Bivalves oysters clams

Phylum Mollusca • Gastropods (Snails, slugs) • Bivalves (oysters, clams, mussels) • Cephalopods (squid, cuttlefish, octopus) • Marine, freshwater, moist land • Secretes shell • Locomotive foot

• Class Gastropoda • Mantle – Tissue that secretes shell • Radula – Rows of rasping teeth for grazing – Modified in predators

Cone shells • Single harpoon tooth – evolved from rowed ancestors – filled with paralyzing venom • Conotoxins – Medical value for specific neural & muscle treatment – Addictive-free pain killers

Class Bivalvia • Clams, oysters, mussels… • Suspension filter feeders – Incurrent & excurrent siphons • Spade-foot for locomotion • Two valves (shells) secreted by mantle – Held closed by powerful adductor muscles

• Class Polyplacophora – Chitons • Graze on microalgae • 8 overlapping plates • Class Scaphopoda – Tusk shells • Open at both ends • Deeper benthic sand/mud

Class Cephalopoda • Squid, octopus, cuttlefish, nautilus • Shell: internal, external, or lacking • Well developed nervous system • Most adapted for active predatory lifestyle

• Muscular foot modified to arms &/or tentacles – Siphon for locomotion • Hydropropulsion • Ink sac or gland – defense • Chromatophores – Adjustable pigment cells • Conotoxins in some

Phylum Arthropoda • Insects, spiders, crabs, shrimp, centipedes • Aquatic and land • External skeleton • Jointed bilateral appendages • Segmented body • Open circulatory system • Many marine crustaceans – Two pairs of antennae – gills

Class Copepoda • Very abundant plankton • Long first antennae

Class Cirripedia • Suspension feeders – Cirri • Protected by calcareous plates • Free-swimming larvae

Decapoda • Shrimps, crabs, lobsters… • 5 pairs walking legs – Thoracic pereopods – 1 st pr as cheliped • 5 pairs abdominal appendages – Pleopods or swimmerets

Amphipoda • Laterally flattened • Shrimp-like & Isopoda • Dorsal-ventrally flattened

Phylum Echinodermata • Spiny skin • 5 classes – Crinoidea--feather stars and sea lilies – Asteriodea--sea stars – Ophiuroidea--brittle stars and basket stars – Echinoidea--sand dollars and sea urchins – Holothuroidea--sea cucumbers • All marine; mostly benthic (sea floor) • Radial symmetry • Water vascular system – Tube feet • Some regenerate asexually

Lophophorates • Lophophore = unique ciliated feeding structure • Bryozoans – Colonial moss animals – Secrete Ca. CO 3 • Brachiopods – Two valves (shells) • Chaetognaths – Lophophore modified – Voracious predators

Phylum Chordata • Notochord – Flexible rod-like structure • Dorsal nerve cord – Tube for nerves • Pharyngeal gill slits – Respiration and feeding • Post-anal tail – Reabsorbed in some species • Invertebrate chordates examples – Urochordata • Tunicates, sea squirts, ascidians – Cephalochordata • lancelets