CLASS CEPHALOPODA Most advanced class

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CLASS CEPHALOPODAMost advanced class
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Squid
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Nautilus
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Cuttlefish
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Octopus
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Cephalopods

• Head Footed modified foot is concentrated in
  head regions with sides of foot drawn out into
  arms and tentacles
• Habitat Marine

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Shell

• Nautilus coiled, series of gas chambers
• Squid shell reduced to PEN (thin, horny, strip
  enclosed by mantle similar to cartilage)
• Octopus shell disappeared

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Locomotion

• Jet propulsion by using siphon to force water out
  
• Crawling octopus

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External Features

• Nautilus 80-90 tentacles with no suction cups
• Octopus 8 arms with suction cups
• Squid/cuttlefish 10 arms
• 8 with suction cups
• 2 retractable without suction cups

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Color Changes

• Chromatophores pigment cells that expand and
  contract to produce color change.
• Used as danger signals, protective coloring, and
  for courtship.
• FYI Cells in skin contain pigment granules. Tiny
  muscle cells surround each elastic chromatophore.
  Contractions pull the cell boundary of the
  chromatophore outward causing it to expand
  greatly pigment becomes dispersed changing the
  color pattern of the animal

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Ink

• All except nautilus have ink sack which empties
  into rectum ink contains the pigment melanin
  (same pigment as human skin)
• Released when the animal is alarmed. The animal
  quickly departs from the scene leaving the ink as
  a decoy to the predator.

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Feeding

• Fish, other mollusks, crustaceans, worms
• Beak like jaws and radula tear prey into pieces
• Octopus and Cuttlefish have poison in saliva

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Circulatory

• Closed
• Heart, blood vessels, capillaries, blood

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Nervous System

• Well-developed brain eyes which are similar in
  construction to vertebrate eyes
• FYI The giant squid has the largest eye of any
  animal, either living or extinct. In a 55-foot
  specimen the diameter was 15.74 inches. In
  comparison, a blue whale's eye has the diameter
  of 4.70 inches, and humans have an eye diameter
  of .94 inches.

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Reproduction

• Dioecious
• Male uses arm to take sperm from own mantle
  cavity and insert into females mantle cavity
• Females tend to eggs, sometimes until death

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Interesting info

• Some squid are bioluminescent (generate light)

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Lets see how you do

• What does gastropoda mean?
• What is the function of a metanephridia?
• What is a trochophore?
• What does polyplacophora mean?

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• 5. What does cephalopoda mean?
• 6. Describe what the shell of a nautilus looks
  like.
• 7. What is the name of the muscles that hold open
  and close a bivalves shell?

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• 8. What is the function of a statocyst?
• 9. Are bivalves monoecious or dioecious?
• 10. What form of courtship do gastropods use?
• 11. How do bivalves move?

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• 12. How do bivalves feed?
• 13. What is torsion?
• 14. Give a benefit and a problem with torsion?
• 15. List the three layers of a mollusk shell.

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• 16. Which cephalopod has 80-90 tentacles with no
  suction cups.
• 17. What is the function of an ocelli?
• 18. What does scaphopoda mean?

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Answers

• What does gastropoda mean?
• Stomach footed
• What is the function of a metanephridia?
• Kidney-like, cleans out wastes
• What is a trochophore?
• Free swimming larval form
• What does polyplacophora mean?
• Many plate bearers

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• 5. What does cephalopoda mean?
• head footed
• 6. Describe what the shell of a nautilus looks
  like.
• coiled with inner chambers
• 7. What is the name of the muscles that open and
  close a bivalves shell?
• adductor muscle

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• 8. What is the function of a statocyst?
• balance
• 9. Are bivalves monoecious or dioecious?
• dioecious
• 10. What form of courtship do gastropods use?
• love darts
• 11. How do bivalves move?
• foot (except scallops who squirt water from
  their shell)

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• 12. How do bivalves feed?
• filter feeding
• 13. What is torsion?
• twisting of anus over head
• 14. Give a benefit and a problem with torsion?
• can draw head in for protection
• - fouling (wastes drop onto head)
• 15. List the three layers of a mollusk shell.
• Periostracum, Prismatic, Nacre

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• 16. Which cephalopod has 80-90 tentacles with no
  suction cups.
• Nautilus
• 17. What is the function of an ocelli?
• eyespot
• 18. What does scaphopoda mean?
• hollow or boat shaped
• HOW DID YOU DO?