Cephalopod
List 4 cephalopods we studied in chapter 10.
1. Octopus
2. Nautilus
3. Squid
4. Cuttlefish
Squid often swim in groups. What is the name of the "group" called?
A shoal
What is the cuttlefish's bone called?
It is called the cuttlebone.
How is a chiton like a gastropod?
It has a single shell that suctions to rocks.
What is a cephalopod's ink used for?
It is used for defense.
Why do squid reproduce only once?
Males die after mating and females die after releasing their eggs.
Where is the cuttlefish's bone located?
It's formed inside the body.
Describe the physical characteristics of a chiton.
They are gray, have 8 plates as a shell and neither have eyes nor arms and are oval shaped.
What two things do cephalopods mostly eat?
1. fish
2. crabs
True of False: a squid's fin is used to push the squid through water.
False.
What is one difference between an octopus and a squid?
Squids swim in the deep, open ocean while octopuses swim and live in shallow water.
How is a nautilus different from other cephalopods?
They have 38-90 arms; once they are born, they begin making an outer shell.
What are 3 interesting details about cephalopods?
1. They can fit into small cracks by changing their shape.
2. They lay eggs in a flower shape.
3. They have 3 hearts.
What does the squid use to move?
The squid uses propulsion.
Why do scientists have to use anesthesia to perform a surgery on an octopus?
Octopuses feel pain like we do.
Thoroughly explain how a nautilus can control how it sinks and rises in water.
It sucks gas in through a tube and water fills the chambers, making it heavier so it sinks. Then to rise, it pushes gas and water out, making it lighter so it can rise.
Describe how chromatophores work and what a cephalopod uses them for.
Describe how jet propulsion works with a cephalopod as the example.
It allows water inside its body and then quickly squeezes the water out, sending a jet stream out, propelling it in the direction it wants to go. To go faster, it can tighten its body into a bullet shape so they glide easily. They can change direction by pointing the hyponome in the opposite direction.
Discuss two ways octopus eyes are different than human eyes.
1. Octopuses don't have a blind spot.
2. The nerves in an octopus eye are behind the photoreceptors and the humans are in front of them.