Chapter 10: Molluscs

Question 1

Phylum ____ is the 2nd largest after Arthopoda

Answer 1

Mollusca

Question 2

There are almost ____ extant species of Phylum Mollusca

Answer 2

90,000

Question 3

What is so important about Molluscs?

Answer 3

They are an extremely important food source and extremely commercially harvested.

Question 4

A healthy ____ depends on healthy oceans

Answer 4

fishery

Question 5

Explain what happens when CO2 amounts increase in the atmosphere

Answer 5

As CO2 levels rise, the acidity of the oceans does as well which causes the amount of biologically available calcium to decrease. This calcium is used for creating strong, healthy shells of molluscs so without it shells are weak and larvae fail to develop normally

Question 6

What are the two primary portions of the basic body plan of a mollusc

Answer 6

Head-foot portion and Visceral mass

Question 7

What is contained within the head food region of a mollusc?

Answer 7

Feeding, cephalic sensory, and locomotor organs

Question 8

The function of the Head-foot region primarily depends on what?

Answer 8

muscular action

Question 9

What is contained within the Visceral mass of a mollusc?

Answer 9

Digestive, circulatory, respiratory, and reproductive organs

Question 10

The function of the Visceral Mass is dependent on what?

Answer 10

Ciliary tracts

Question 11

Describe the mantle of a mollusc

Answer 11

Formed by two folds of skin
Internal space is the mantle cavity

Question 12

What is the function of the mantle?

Answer 12

Protection and secretes the shell

Question 13

Modifications of structures produce great ___ of the body plans

Answer 13

diversity

Question 14

What other structures are found within the head-foot region?

Answer 14

Mouth, sensory organs, chemoreceptors, statocysts, tactile sensors, brain

Question 15

Describe a radula (function, feel)

Answer 15

Unique to molluscs, located in mouth, Tongue-like organ
Function- helps feed and carry food particles toward digestive tract

Question 16

What is the foot portion of the head-foot region adapted for?

Answer 16

Locomotion and attachment to substrate

Question 17

Describe the modification of the foot that Limpets have

Answer 17

Attachment disc that creates suction

Question 18

Describe the modification of the foot that Bivalaves have

Answer 18

“hatchet foot”

Question 19

Describe the modification of the foot that squids/octopuses have

Answer 19

Funnel for jet propulsion

Question 20

How many layers does a mollusc shell have? What are they called?

Answer 20

3;Periostracum, Prismatic layer, Nacre

Question 21

What layer of the shell is the outmost?

Answer 21

Periostracum

Question 22

The Periostratcum is composed of ____.

Answer 22

conchiolins

Question 23

What are conchiolins? Function?

Answer 23

Composition of the Periostratcum; protective protein, protects from erosion

Question 24

What is the Prismatic layer composed of?

Answer 24

densely packed prisms of calcium carbonate

Question 25

What is the innermost layer of a molluscs shell called?

Answer 25

Nacre

Question 26

What is unique about the nacre layer?

Answer 26

It is secreted continuously through an animals life and become thicker

Question 27

What special event occurs in the nacre?

Answer 27

Pearl formation

Question 28

Explain how a pearl is formed

Answer 28

The nacre layer begins to cover a foreign object such as dirt between the shell and the mantle continuously to avoid irritation. Overtime, this dirt becomes a shiny spherical object we call a pearl

Question 29

What is unique about a molluscs circulation system

Answer 29

It is an open system, blood is not contained within the vessels

Question 30

_____ have a closed circulatory system

Answer 30

Cephalpods

Question 31

What does fertilization result in?

Answer 31

An embryo

Question 32

What is the 2nd swimming larval stage structure called?

Answer 32

Veliger

Question 33

What classes of Molluscs are discussed in this chapter

Answer 33

Polyplacophora & Gastropoda

Question 34

____ is the most diverse class of molluscs

Answer 34

Gastropods

Question 35

Most Gastropods have a hard proteinaceous plate called a _____.

Answer 35

Operculum

Question 36

What does an Operculum do?

Answer 36

Acts as a trapdoor and covers the shell when the body withdraws inside

Question 37

What is an example of Herbivore Gastropods

Answer 37

Turban snails

Question 38

What do scavenger Gastropods feed on? Example

Answer 38

Dead and decaying flesh; mud snails

Question 39

What do driller/borer Gastropods do? What is an example?

Answer 39

They drills holes into shells with their radula (4 days); Moon snail

Question 40

What is an example of carnivore Gastropods

Answer 40

Cone snails

Question 41

What is unique about cone snails

Answer 41

they have a radula that has been modified into a harpoon with venom to kill prey

Question 42

What are the 3 subclasses of Gastropods

Answer 42

Prosobranchia, Opisthobranchia, & Pulmonata

Question 43

____ is the largest subclass of Gastropods

Answer 43

Prosobranchia

Question 44

What are examples of Prosobranchia

Answer 44

Periwinkles, Limpets, Abalones, Cowries

Question 45

What is an example of subclass Opisthobranchia

Answer 45

Sea hare & Nudibranchs

Question 46

What is an example of subclass Pulmonata?

Answer 46

Giant land snail

Question 47

What is different about subclass Pulmonata?

Answer 47

Lack gills, contain land and freshwater slugs/snails

Question 48

What is the common name for Class Polyplacophora?

Answer 48

Chiton

Question 49

What Class is described as bearing many plates”

Answer 49

Class Polyplacophora (Chitons)