MOLLUSCA

Question 1

General Characteristics of Molluscs?

Answer 1

Foot, mantle, shell.
Marine, freshwater, terrestrial
Coelomate protostomes (Spiralia).

Question 2

5 classes of Mollusca

Answer 2

Class Polyplacophora (chitons)
Class Gastropoda (abalone, sea slugs, sea hares, terrestrial slugs and snails)
Class Bivalvia (clams, mussels, oysters, scallops)
Class Scaphapoda (tusk shells)
Class Cephalopoda (nautilus, octopus, squid, cuttlefish)

Question 3

What type of symmetry?

Answer 3

Bilateral

Question 4

Reduced coelom but with an extensive _______ comprising an open circulatory system with compartmentalized heart.

Answer 4

hemocoel

Question 5

What are the 3 body regions

Answer 5

head, foot, visceral mass

Question 6

Define the Mantle

Answer 6

thick epidermal-cuticular covering that secretes the shell

Question 7

What is housed within the mantle cavity?

Answer 7

ctenidia (gills), anus, opening to kidneys and reproductive tract, and osphradia (sense organs)

Question 8

What is the radula?

Answer 8

a ribbon of recurved chitinous teeth that often functions as a scraper to remove food particles for ingestion

Question 9

What controls the radula?

Answer 9

the odontophore

Question 10

What type of kidneys?

Answer 10

Metanephridial

Question 11

What type of larvae?

Answer 11

Trochophore and veliger

Question 12

What stage does torsion occur in gastropods?

Answer 12

Veliger larvae stage

Question 13

3 layers of the body wall?

Answer 13

cuticle, epidermis, muscle layers

Question 14

How does water flow thru the mantle cavity?

Answer 14

driven by cilia
In cavity —> over gills —> over nephridiopores and anus —> out.

Question 15

What are the 3 layers of the shell?

Answer 15

Three layers: periostracum made of scleretized proteins (conchin), prismatic made of CaCO3 in columnar conchin matrix, and nacreous made of CaCO3 with some conchin in sheet-like pattern (mother-of-pearl).

Question 16

Which animals have reduced shells?

Answer 16

sea hares, squid pen, cuttle bone

Question 17

Which animals have lost shells?

Answer 17

Octopus, nudibranchs

Question 18

What happens during torsion on gastropods? What does it result in?

Answer 18

Rotation of visceral mass and overlying mantle and shell 180 degrees with respect to foot and head.
Gut ends up U-shaped and incipient organs are switched left to right.

Question 19

How do gastropods and polyplacophorans move?

Answer 19

Crawling (direct and indirect waves)
Mucus alternately acts as a glue and allows sliding.
Some gastropods use cilia (moon snails).

Question 20

How do Bivalves move?

Answer 20

Burrowing, byssal threads, swimming

Question 21

How do Cephalopods move?

Answer 21

Radial and circular muscles. Contraction of circular muscles forces water out siphon or funnel for swimming.
Crawling along substratum.

Question 22

Describe the Cephalopod nervous system

Answer 22

Well developed -
Brain with lobes.
Large nerve to all parts of body.
Large optic nerves.
Memory in octopus.

Question 23

What do osphradia do?

Answer 23

chemosensory and sensing sediment

Question 24

What do statocysts do?

Answer 24

balance and oreintation

Question 25

What type of sense organs are tentacles and rhinophores?

Answer 25

chemosensory

Question 26

What are chromatophores?

Answer 26

Cells for color change in cephalopods. Contain pigments and are under neuronal and hormonal contol.

Question 27

what is Macrophagy

Answer 27

eating "large" things

Question 28

What is Microphagy

Answer 28

eating "small" things

Question 29

How do gastropods eat?

Answer 29

using their radula

Question 30

How do Cephalopods eat?

Answer 30

Cephalopods highly mobile predators. Catch prey with suckered arms. Neurotoxins associated with beak in octopus.

Question 31

How do Bivalves eat?

Answer 31

Ctenidia modified for particle capture

Question 32

What is the function of labial palps in Bivalves?

Answer 32

sorting food particles

Question 33

What are pseudofeces? (Bivalves)

Answer 33

non-organic particles that are excreted (they never entered the digestive system - kicked out by labial palps)

Question 34

Complete or Incomplete digestive system?

Answer 34

Complete

Question 35

What is the purpose of a crop?

Answer 35

Food storage

Question 36

What type of circ system?

Answer 36

Open - except for Cephalopods (closed)

Question 37

How do terrestrial gastropods do gas exchange?

Answer 37

they have a "lung" - a vascularized mantle cavity

Question 38

What kind of waste do aquatic molluscs excrete? terrestrial?

Answer 38

aquatic - ammonia terrestrial - uric acid

Question 39

Hermaphroditic or gonochoristic?

Answer 39

most gonochoristic (bivalvia, cephalopoda, gastropoda) some hermaphroditic (simultaneous and sequential) (gastropoda)

Question 40

What type of cleavage?

Answer 40

spiral

Question 41

mouth from ______?

Answer 41

blastopore

Question 42

cell fate determined early or late?

Answer 42

early

Question 43

What type of development? (direct, indirect, mixed)

Answer 43

can be all terrestrials and cephalopods direct nudibranchs mixed

Question 44

what is the excretion organ?

Answer 44

paired tubular metanephridia

Question 45

Those with indirect development - what type of larva?

Answer 45

Free swimming trochophore larva