molluscs

Question 1

classes

Answer 1

polyplacophora
scaphopoda
gastropoda
bivalvia
cephalopoda

Question 2

gulf/marsh periwinkle

Answer 2

Littorina irrorata
herbivorous, feeds on algae

Question 3

knobbed whelk

Answer 3

Busycon carica

Question 4

spiral of whelks and lines separating them

Answer 4

whorls and sutures

Question 5

oyster drill

Answer 5

Urosalpinx cinerea
carniverous, uses radula and acidic (CaC) secretion to bore thru bivalve shells

Question 6

Whelks

Answer 6

prey on clams
use regella on foot and edge of shell to wedge into clam’s opening

Question 7

dextral

Answer 7

whelks
“right-handed”

Question 8

Euspira genera

Answer 8

moon snails
very wide and flat foot
edge of mantle can roll upwards and partly cover the shell
radula is tongue-like and covered w teeth

Question 9

what are siphons in Quahogs used for?

Answer 9

mostly gas exchange
suspension feeders (form of filter feeding)

Question 10

Tagelus genus

Answer 10

long rectangle guys, spend lives in burrows so muscles holding valves together are very weak

Question 11

cockles

Answer 11

type of bivalve
short siphons, meaning they live close to surface of substrate/very shallowly buried

Question 12

general morphology of molluscs

Answer 12

shell
mantle
foot
mantle cavity
visceral mass
triploblastic/bilateral coelomate hemocoel
complete gut

Question 13

mantle

Answer 13

secretes shell if the organism has one

Question 14

foot

Answer 14

flattened muscular tissue used for crawling/clinging to surfaces
bivalve foot: modified for burrowing
cephalopod foot: modified into arms/tentacles

Question 15

mantle cavity

Answer 15

typically houses gill/lung, anus, nephridopores

Question 16

visceral mass

Answer 16

refers to tissues + organs protected by shell

Question 17

triploblastic/bilateral coelomate hemocoel

Answer 17

hemo-blood: “blood coelum”
open circulatory system in everyone except for cephalopods

Question 18

open vs closed circulatory system

Answer 18

open- works for most sedentary animals, not active
- blood is directly in contact with cells and tissues, heart usually has a slit that pushes blood out when engaged and draws it back in when relaxed

Question 19

complete gut

Answer 19

contains mouth and anus, one direction of movement for food
gut highly differentiated regionally
crystalline style common in bivalves and gastropods

Question 20

crystalline style

Answer 20

gelatinous rod containing digestive enzymes, twirled by beating cilia to release enzymes when rubbing against gastric shield and mix them w food

Question 21

parts of body wall + shell oof molluscs

Answer 21

pallial muscle
shell
extrapallial cavity

Question 22

pallial muscle

Answer 22

connects shell to mantle

Question 23

shell

Answer 23

periostracum
prismatic layer
nacreous layer

Question 24

extrapallial cavity

Answer 24

space btwn shell and mantle epithelium

Question 25

periostracum

Answer 25

outermost portion of shell

Question 26

prismatic layer

Answer 26

part of shell btwn periostracum and nacreous layer

Question 27

nacreous layer

Answer 27

layer btwn prismatic layer and extrapallital space pearly/iridescent material of the animal

Question 28

polyplacophora (chitons)

Answer 28

marine, rocky substrates 8 shell plates mantle = girdle herbivores, feed on algal films radula teeth capped w/ magnetite foot

Question 29

polyplacophoran mantle

Answer 29

specialized to be thick and rubbery- this is where plates are embedded

Question 30

polyplacophoran foot

Answer 30

very broad and flat- allows them to adhere to surfaces very tightly

Question 31

cephalization in polyplacophora?

Answer 31

very little

Question 32

polyplacophoran mantle cavity

Answer 32

"trough" btwn foot and mantle paired gills located here

Question 33

what kinds of animals are in the class gastropoda?

Answer 33

snails, slugs, nudibranchs, sea hares

Question 34

characteristics of gastropods

Answer 34

largest group of molluscs gastro-stomach, pod-foot (stomach-foot) obvious cephalization often have shells that act as portable retreats torsion

Question 35

gastropods that don't use shells as portable retreats

Answer 35

limpets, abalone, slipper shells

Question 36

torsion

Answer 36

twisting of visceral mass by 180 deg occurs in veliger stage of gastropods

Question 37

veliger stage

Answer 37

larval stage in gastropods rudimentary shell, foot visible, 2 large ciliated velum

Question 38

pre-torsion veliger

Answer 38

mantle cavity at posterioir end osphradium also posterior

Question 39

osphradium

Answer 39

sensory tissue

Question 40

disadvantages of torsion

Answer 40

fouling- repositioning of posterior tissues so that wastes are excreted near the head

Question 41

evolutionary changes made by gastropods to compensate for disadvantages of torsion

Answer 41

ciliary tracts to carry away waste openings/keyholes to excrete wastes (limpets, abalone)

Question 42

hypothetical advantages of torsion in gastropods:

Answer 42

- allows head to be drawn in before foot- incr. chances of sublethal predation vs lethal - torsion places osphradium at the anterior end - allows mass to be centered over the organism in cases where the apex of the shell spiral is drawn out anteriorally

Question 43

reproduction in gastropods

Answer 43

many gonochoristic some hermaphroditic

Question 44

gonochoristic repro in gastropods

Answer 44

spawning (broadcast spawning) internal fertilization via copulation

Question 45

broadcast spawning

Answer 45

in gastropods gametes emitted to seawater, fertilization occurs in seawater,

Question 46

internal fertilization via copulation in gastropods

Answer 46

females may add protective substances to egg case coverings

Question 47

which gastropods are hermaphroditic?

Answer 47

sea hares + slugs, nudibranchs

Question 48

gastropod egg development

Answer 48

may occur in water or egg casings

Question 49

gastropod larval stages

Answer 49

1- trochophore (spinning top) 2- veliger (when torsion occurs)

Question 50

gastropods that don't use shells as portable retreats

Answer 50

limpets, abalone, slipper shells