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Gastropods (Snails, slugs) Bivalves (oysters, clams, mussels) Cephalopods (squid, cuttlefish, octopus) Marine, freshwater, moist land Secretes shell Locomotive foot. Phylum Mollusca. Class Gastropoda Mantle Tissue that secretes shell Radula Rows of rasping teeth for grazing
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Gastropods (Snails, slugs) Bivalves (oysters, clams, mussels) Cephalopods (squid, cuttlefish, octopus) Marine, freshwater, moist land Secretes shell Locomotive foot Phylum Mollusca
Class Gastropoda Mantle Tissue that secretes shell Radula Rows of rasping teeth for grazing Modified in predators
Single harpoon tooth evolved from rowed ancestors filled with paralyzing venom Conotoxins Medical value for specific neural & muscle treatment Addictive-free pain killers Cone shells
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 Bivalvia
Class Polyplacophora Chitons Graze on microalgae 8 overlapping plates Class Scaphopoda Tusk shells Open at both ends Deeper benthic sand/mud
Squid, octopus, cuttlefish, nautilus Shell: internal, external, or lacking Well developed nervous system Most adapted for active predatory lifestyle Class Cephalopoda
Muscular foot modified to arms &/or tentacles Siphon for locomotion Hydropropulsion Ink sac or gland defense Chromatophores Adjustable pigment cells Conotoxins in some
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 Phylum Arthropoda
Very abundant plankton Long first antennae Class Copepoda
Suspension feeders Cirri Protected by calcareous plates Free-swimming larvae Class Cirripedia
Shrimps, crabs, lobsters… 5 pairs walking legs Thoracic pereopods 1st pr as cheliped 5 pairs abdominal appendages Pleopods or swimmerets Decapoda
Laterally flattened Shrimp-like Dorsal-ventrally flattened Amphipoda & Isopoda
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 Phylum Echinodermata
Lophophore = unique ciliated feeding structure Bryozoans Colonial moss animals Secrete CaCO3 Brachiopods Two valves (shells) Chaetognaths Lophophore modified Voracious predators Lophophorates
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 Phylum Chordata