Chapter 10 Part 2: Molluscs

Question 1

What organisms are contained within Class Bivalvia?

Answer 1

Mussels, clams, scallops, oysters, and shipworms

Question 2

Describe the great variety in size of Bivalves

Answer 2

Tiny seed shells to Giant South Pacific clams

Question 3

What is the scientific name (genus) of Giant South Pacific clams

Answer 3

Tridacna

Question 4

True/False: All Bivalves are marine and aquatic

Answer 4

False: all are aquatic but not all are marine

Question 5

How do Most bivalves feed?

Answer 5

Suspension feeders; depend on ciliary currents produced by gills for food collection

Question 6

What structures do Bivalves lack?

Answer 6

head, radula, little cephalization

Question 7

Bivales shells are held together dorsally by what?

Answer 7

Hinge ligament

Question 8

_____ ____ work in opposition to hold valves together

Answer 8

Adductor muscles

Question 9

What is an umbo? Where is it located

Answer 9

The oldest part of a bivalve shell; above hinge ligament

Question 10

What is the main function of the umbo?

Answer 10

Protection

Question 11

What unique feature do shipworms have on their shell?

Answer 11

Microscopic teeth that allow them to burrow through wood

Question 12

Describe the circulation process in bivalves

Answer 12

3 chambered heart

Question 13

Describe the nervous system of bivalves

Answer 13

3 pairs of ganglia; overall poorly developed sense organ

Question 14

What is the exception to the nervous system being poorly developed? Why?

Answer 14

Scallops; have around 200 ocelli on the shell that contain corneas, retinas, and lenses

Question 15

What is unique about the digestion of shipworms?

Answer 15

Have a symbiotic relationship with bacteria in a special organ that produces cellulase for wood digestion

Question 16

What is unique about Tridacna clams in terms of feeding and digestion?

Answer 16

Have a unique relationship with zooxanthellae that produce food for the clam

Question 17

How do most bivalves move?

Answer 17

By extending the foot out of the shell

Question 18

Oysters are considered ____. And secrete ____ to attach shells to surface

Answer 18

sessile; cement

Question 19

Mussels are considered ____. And secrete ____ to surfaces

Answer 19

sessile; byssal threads

Question 20

How do scallops move around?

Answer 20

Clapping their shells to propel themselves

Question 21

How many neurons do octopuses have? In what part of their bodies are most of these neurons
found?

Answer 21

500 million; arms

Question 22

Describe the structure and function of chromatophores.

Answer 22

Speckled across the surfaces like freckles containing pigments for the black, red and yellow colors.

Question 23

Describe the structure and function of iridophores.

Answer 23

A layer of reflective structures below chromatophores that produce green and blue metallic coloring contain reflectin.

Question 24

Describe the structure and function of leucophores.

Answer 24

A layer of reflective structures below iridophores produces white colors.

Question 25

Describe the way(s) an octopus uses papillae. What is the advantage of these structures?

Answer 25

It gives the skin bumps and ridges, allowing it to change its skin’s texture and blend into the environment.

Question 26

Other than its eyes, what other structure does an octopus use to see?

Answer 26

Skin

Question 27

How does the “coconut-carrying octopus” demonstrate an octopus’s planning ability?

Answer 27

When traveling far distances with no shelter, they will take coconut halves for protection when they need to stop and rest. Acts as a shell. Has to imagine the future and know that they will need the coconut later on.

Question 28

Explain the ecological intelligence hypothesis.

Answer 28

Complex behaviors evolved to meet the challenges of predation, foraging, and competition. Especially after the loss of their shell octopuses could have been required to outsmart predators to survive.

Question 29

Describe cephalopod locomotion.

Answer 29

They move through jet propulsion, where water is expelled through the siphon and pushes them forward