Class Cephalopoda (Phylum Mollusca)

Question 1

What does “cephalopoda” mean?

Answer 1

“head foot”

Question 2

locomotion

Answer 2

• lateral fins (squids): good for sustained or precise swimming
  
  • jet propulsion: fast! (squids & octopus)
  • fill mantle cavity, use funnel to push water out
  • panic use, usually for running away
  • ink released
  • pen: helps keep body rigid

Question 3

Feeding

How do they hunt?

Answer 3

• hunt by sight – can see very well in water
• eyes are convergent w/ vertebrate eyes
• have lens, pupil, cornea, retina: complex!

Question 4

Feeding

How do they catch their prey?

Answer 4

• Catch prey w/ arms & tentacles (good control)
  
  • they’re covered in suckers
  • can control each sucker & gravity suction of each

Question 5

Feeding

What do they use radula for?

Answer 5

• squid: scrape flesh from bone
• octopus: use it for boring holes in bivalve shells
  
  • injects venom in mantle cavity of clam
  • they’re venomous

Question 6

Feeding

How is food moved?

Answer 6

• food moved via peristalsis (like toothpaste movement)
• don’t use cilia

Question 7

What kind of circulatory system do they have?

Answer 7

• closed – they have capillaries
• huge advantage, allows oxygen directly into tissues & organs

Question 8

Circulatory System

How many hearts do they have?

Answer 8

• 3 hearts
  
  • 2 branchial hearts → pump blood to gills
  • 1 systemic heart → pumps blood to body

Question 9

What is their nervous system like?

Answer 9

• well-developed
• no dorsal nerve, have ganglia
• “smart”
  
  • learn by observation
  • have camouflage
  • can assume 7 different body forms
  • not dominant b/c solitary & territorial and only live 5 years