Presentation on theme: "Today’s Objectives: TSW list key characteristics of mollusks, including, but not limited to, Major organs/organ systems Major classes and representatives."— Presentation transcript:
1 Today’s Objectives:TSW list key characteristics of mollusks, including, but not limited to,Major organs/organ systemsMajor classes and representativesEconomic importanceEvolutionary historyOther major characteristics
23 Cephalopoda – Head Foots Octopi, squid, nautili, cuttlefishTentaclesJet PropulsionClosed Circulatory System
24 Cephalopoda Shell External on nautili Internal in squid (pen) Internal in cuttlefish (cuttlebone)Absent in octopi
25 Cephalopoda Locomotion Use siphon for jet propulsionSqueeze mantle cavity forcefullySometimes have external “wings” or fins for steering or slow locomotionNautili use internal air for neutral buoyancy
26 Cephalopoda Feeding Most capture prey by sight Use arms or tentacles to grab (sometimes have hooks and suckers)Bring prey to beaked mouthMuscular digestive systemDigestion in stomach and cecumAnus near the funnel
27 Cephalopoda Respiration & Circulatory Systems Closed ciculatory system – more efficient3 heartsHigh metabolic ratesRespiration through gills
28 Cephalopoda Nervous System Complex brainsVery advanced, large eyesStatocystsTouch receptorsChemoreceptorsChromatophores – color changing, signallingSome bioluminescentInk gland
29 Cephalopoda Reproduction & Development All are dioeciousMales have testes and package sperm in spermatophoresFertilization mostly internal in back of female’s mantle cavityOctopi have external fertilization of eggsOften males have hectocotylusAll larval development inside eggs.
30 Economic Importance of Cephalopods Research on nervous systemBaitFood – calamariMinerals for pets – cuttlebone
31 Representative Cephalopods Loligo – common squidArchiteuthis dux – giant squidOctopus dofleini – Giant pacific octopus
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