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Phylum Mollusca

Phylum Mollusca. Class Scaphopoda Class Cephalopoda. Class Scaphopoda. Defining characteristics Tusk shaped conical shells, open at both ends Development of anterior thread-like adhesive feeding tentacles Elongated tapering tubular shells that burrow in sandy bottoms. Class Scaphopoda.

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Phylum Mollusca

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  1. Phylum Mollusca Class Scaphopoda Class Cephalopoda Class Scaphopoda & Cephalopoda

  2. Class Scaphopoda • Defining characteristics • Tusk shaped conical shells, open at both ends • Development of anterior thread-like adhesive feeding tentacles • Elongated tapering tubular shells that burrow in sandy bottoms Class Scaphopoda & Cephalopoda

  3. Class Scaphopoda • Commonly called tooth shells or tusk shells • Have lost ctenida along with ability to filter feed • Never spirally wound but grows linearly Class Scaphopoda & Cephalopoda

  4. Class Cephalopoda • Defining characteristics • Closed circulatory system • Foot modified to form flexible arms and siphons • Ganglia fused to form a large brain encased in a cartilaginous cranium Class Scaphopoda & Cephalopoda

  5. Cephalopod Characteristics • The most highly organized of all the molluscs, the foot is closely associated with the head • Can be as large as 1,000kg. and 18m. • Architeuthis spp. Class Scaphopoda & Cephalopoda

  6. Defensive Mechanisms • Since they are susceptible to predation they have evolved chromatophores • An ink sac that is associated with the digestive system and discharged out the anus Class Scaphopoda & Cephalopoda

  7. Sensory & Nervous System • Eyes • All but the nautilus have image forming eyes that are like mammals • Convergent evolution Class Scaphopoda & Cephalopoda

  8. Reproduction • Sexes are separate • Males have one modified arm (hectocotylus) for sperm transfer • Sperm are enclosed in packets called spermatophores Class Scaphopoda & Cephalopoda

  9. Squid • 10 sucker bearing arms surround the mouth • 2 longer tentacular arms can shot forward and capture prey • Form large schools and feed on crustaceans, and fishes • The shell is reduced and lies under the mantle • Large folded gills and a circulatory system distribute oxygen quickly Class Scaphopoda & Cephalopoda

  10. Squid Internal Anatomy Class Scaphopoda & Cephalopoda

  11. Squid Locomotion • The foot forms the funnel • The upper end of the mantle is extended into a pair of triangular fins • Can move very quickly • 5-10 m/s Class Scaphopoda & Cephalopoda

  12. Octopus • Have 8 arms all equal in length • Rows of suckers from base to tip • Compact body with a greatly reduced shell • The body is extremely flexible and assumes a streamlined shape when swimming with squid-like jets through the funnel Class Scaphopoda & Cephalopoda

  13. Learning and Memory • Benthic feeders on bivalves, crabs and fishes • Amazing ability to learn quickly and remember for several weeks Class Scaphopoda & Cephalopoda

  14. Could an Octopus be your next Professor? Class Scaphopoda & Cephalopoda

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