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Class Cephalopoda. Predators specialized for locomotion Cephalopods include octopuses, squid, nautiluses and cuttlefish. Live in marine environments Only some have a shell Foot is modified into tentacles , usually with suckers used to capture prey. Class Cephalopoda.
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Class Cephalopoda • Predators specialized for locomotion • Cephalopods include octopuses, squid, nautiluses and cuttlefish. • Live in marine environments • Only some have a shell • Foot is modified into tentacles, usually with suckers used to capture prey
Class Cephalopoda • Most cephalopods have complex eyes • Largest invertebrate brain • Most intelligent mollusk (learning & memory) • Only mollusks with a closed circulatory system • http://www.iteachbio.com/Marine-Biology/OctopusIntelligence.mov http://www.iteachbio.com/Marine-Biology/OctopusandCoconutTool.mov
Class Cephalopoda - Nautilus • External shell of the nautilusis made buoyant by a series of gas chambers. • 60-90 short, suckerless tentacles http://www.youtube.com/watch?v=L8qwRCs_7x0
Class Cephalopoda - Cuttlefish • Cuttlefish have a small curved internal shell, completely enclosed by the mantle.
Class Cephalopoda - Squid • Squid have a small strip of a shell called a pen, which is enclosed in the mantle. • Have 8 arms and 2 tentacles (w/ suckers) surrounding mouth • Giant squid is largest living invertebrate
Class Cephalopoda - Locomotion • Cephalopods swim by forcing water out of the mantle cavity through a siphon, or funnel, underneath the head • Funnel can move around animal can move in any direction via jet propulsion
Protection • Color changes affected by chromatophores (pigment cells) • Allows them to blend into their background • Squirting out water by jet propulsion helps escape predators • Octopuses & squids also release an inky substance from an ink sac to distract predators
Feeding • Cephalopods are carnivores with beak-like jaws surrounded by tentacles • Have a powerful parrot-like beak that is used to tear prey apart. • They also have a powerful radula to scrape away flesh • In some of the octopuses the salivary glands are modified poison glands
Class Cephalopoda - Reproduction • Cephaolopods are separate sexes . • Juveniles hatch directly from eggs – no free-swimming larvae. • One arm of male removes a spermatophore (elongated packet of sperm) from mantle cavity and inserts it into female.
The Mimic Octopus An Indonesian octopus mimicing a flatfish (above) and a lionfish (right)
Mollusk Nervous System • Gastropods, bivalves, and chitons have ganglia • Clusters of nerve cells • Ganglia replace the brain • Cephalopods have a large brain
Sources • http://brainbeau.com/cihs/MarineBiology/Chapter7/Mollusks-Phylum_Mollusca_files/frame.htm • http://www.biologyjunction.com/Molluscs%20revised%20cam.pptx • http://faculty.mwsu.edu/biology/jon.scales/Courses/Zoology/lectoutlines/11_mollusca.ppt