Mollusks: Cephalopods Octopus, Squid, Cuttlefish

Cephalopods

• Fierce Predators – Large brains – Complex sensory structures – Rapid locomotion – Grasping tentacles

• Octopus vs. Shark

Physical Characteristics

• Anterior– Tentacles and jet

propulsion

• Mantle (Shell) – Nautilus: only

cephalopod w external shell

• Fills it with gasses to help w buoyancy

– Squid: internal shell, helps with structure

– Octopus: NO SHELL

Locomotion

• Jet like propulsion out of mantle – Squid: uses it for

catching prey • Up to 25 mph!

– Squid catching cameras.

– Octopus: escape method

Digestion

• Enzymes digest food in stomach– Moves to anus– Expelled during

jet propulsion

Nervous/Sensory System

• Very large brain – Dedicated to

movement/control of tentacles

– Very smart: octopus are known to problem solve

– Curious

• Giant Octopus• Octopus Opening lid • Eyes: advanced, similar

to vertebrate eyes – Convergent evolution

Predator Adaptations

• Locate prey by sight• capture prey w

tentacles/ suction cups – Tentacles reinforced w

protein

• Eat using a radula – Cuttlefish: small

invertebrates – Octopus:

• Nocturnal: snails, fish, crustations

Predator Adaptations

• Chromatophores – Cells that can change

colors

• Tiny muscles contract or expand and chromatophores quickly change color– Alarm response– Defensive – Blend in w environment– Courtship – Bioluminescence

• Cuttlefish in love