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Flashcards in Mollusca Test Deck (31):
1

Radula

Tongue with rough scraping teeth used for feeding

2

What are two methods mollusk use to feed?

Filter feeders (clams, oysters) and predation (squid, octopus)

3

All classes EXCEPT ___________ have a radula

Bivalves and aplacophora

4

Visceral mass

Digestive system, excretory system, reproductive organs

5

What does the mantle do?

Secretes shell

6

What are the 3 layers of shell?

Periosteum
Prismatic
Nacreous

7

What is the outside layer of a shell?

Periosteum

8

What is the middle layer of a shell that gives it strength?

Prismatic

9

What is the inner "mother of pearl" layer of a shell?

Nacreous

10

Most mollusks have an _____ circulatory system

Open

11

Because there's no distinction between blood and interstitial fluid this is called

Hemolymph

12

What are gills also called

Ctenidia

13

What are the kidneys called?

Nephridia

14

What are the seven classes of mollusca?

-gastropada
-bivalvia
-Cephalopoda
-Scaphopoda
-aplacophora
-monoplacophora
-polyplacophora

15

How do most mollusks reproduce?

External fertilization

16

What are characteristics of gastropada?

Shell conical, coiled, or absent

17

What is the largest class of mollusks?

Gastropada

18

What is torsion?

Developmental process in which the body twists into permanent loop that rearranges organs and brings them together allowing body to draw into spiral shell

19

What is the operculum?

Protects the mouth of the gastropod and acts as a trap door

20

What is the gastropod that has no shell?

Nudibranch (sea slug)

21

What are characteristics of bivalvia?

-contain mollusks with two shells
-laterally compressed for filter feeding
-shell closed by adductor muscles
-not all bivalves burrow, mussels secrete byssal threads to attach to rocks, oysters cement left shell to hard surface
-scallops live unattached, can swim short distances

22

How do cuttlefish differ from squid and octopuses?

By having an internal shell for buoyancy (cuttlebone)

23

How do squid differ from cuttlefish and octopuses?

Streamlined body for open water

24

How are octopuses different from cuttlefish and squid?

Have no shell and live in rocky reefs

25

Nautilus

Have external shell and can live in depths of 2000 feet
-has most tentacles or arms

26

What are characteristics of the class Cephalopoda?

-use siphon to rapidly shoot water to escape/catch food
-siphon can rotate in any direction to change speed/ direction
-all but nautilus have ink sac opening
-have pigment called chromatophores

27

Monoplacophora

-"one plate"

28

Polyplacophora

Have oval shell consisting of 8 plates bounded by girdle
-ex: chiton

29

Scaphopoda

(Tusk shells) marine sand burrowers with tusk or toothed shells

30

Aplacophora

Lack of shell
-ex: worm like species

31

All mollusks have

Mantles