How Cool are Cephalopods? (Test Two)

Question 1

Cephalopods are in which Phylum and which Class?

Answer 1

Phylum Molluska

Class Cephalopoda

Question 2

What Phylum, Class and Order are Nautilus?

Answer 2

Phylum Molluska

Class Cephalopoda

Order Nautiloidea

Question 3

Why are Nautilus called a “living fossil”?

Answer 3

Because they have remained relatively unchanged for hundreds of millions of years.

Question 4

Where do Nautilus reside?

Answer 4

They only live in the Indo-Pacific in deep slopes of coral reefs.

Question 5

How do Nautilus get their food?

Answer 5

They are scavengers and opportunistic hunters, and they find food using their sense of smell.

Question 6

How do Nautilus regulate buoyancy?

Answer 6

They either push air out of their shell chambers to go down or suck in air to go up.

Question 7

What Phylum Class and Order are Octopuses?

Answer 7

Phylum Molluska

Class Cephalopoda

Order Octopoda

Question 8

How old is the oldest fossil of Octopuses?

Answer 8

296 million years old

Question 9

What are the 4 main characteristics of the Order Octopoda?

Answer 9

They are soft bodied (no shell)

Most all are predatory

Most are solitary, some social

Live in every ocean

Question 10

What Phylum, Class, and Order are Squids in?

Answer 10

Phylum Mollusca

Class Cephalopoda

Order Teuthoidea

Question 11

What are the 4 main characteristics of the Teuthoidea order?

Answer 11

Some are solitary, others live in large schools

They are soft-shelled

They are carnivorous predators

They live in every ocean

Question 12

Why have squid and octopus populations been growing steadily when many marine populations have been shrinking?

Answer 12

1. Rapid growth
2. Short lifespans (fast evolution)
3. Mobility
4. Flexible behavior (those crazy brain arms)

Question 13

Briefly explain the stages of eye complexity in cephalopods

Answer 13

1. First there was just a layer of pigment and nerve cells (pigment spot)
2. Next, that spot became a divot (detected light direction)
3. Thirdly, the light hitting the pigment became centered into a pin-hole like slit and the optic nerve appeared
4. Lastly, is the complex octopus eye

Question 14

What is the chief difference between an octopus eye and our eye?

Answer 14

The optic center in humans is in the brain

In octopuses, the optic ganglion is positioned in the back of their eye

Question 15

What is convergent evolution?

Answer 15

Convergent Evolution is when distantly related groups independently evolve similar traits due to environmental or ecological similarities.

Question 16

What are three analogies to convergent evolution?

Answer 16

1. birds wings and bat wings
2. dolphin and shark body shapes
3. image forming eyes in highly mobile, predacious animals

Question 17

What is a ganglia?

Answer 17

neuron bundles

Question 18

Why might octopuses be capable of observational learning?

Answer 18

Because their lobes with millions neurons are located in their arms and not a central brain.

Largest brain of any known vertebrate, with several lobes spread out.

Question 19

Explain the basic structure of one neuron in a bundle.

Answer 19

Consists of a cell body with a thin axon that leads to the terminal (nerve ending)