Phylum Mollusca Flashcards
0
Q
Class polyplacophora
A
- chitons
- intertidal zone
- strong foot
- use radula to feed
- primitive
- 8 valves to protect soft tissues
1
Q
Mollusk
A
- soft-bodied
- have internal or external shell
2
Q
Class Gastropoda
A
- snails, slugs, limpets, nudibranchs
- shell-less or single shelled
- muscular foot to move
- visceral mass 180o counterclockwise inside shell
3
Q
Defense:
A
- nocturnal
- pull into shell
- toxic chemicals
- brightly coloured
4
Q
Shelled Gastropods
A
- single non-twisted shell
- ex. Abalone, limpet
- single twisted shell
- ex. Garden snail
5
Q
Naked Gastropods
A
- garden slugs
- mantle-> saddle
- nudibranchs
6
Q
Why mucous?
A
- prevents dessication
- ease of movement
- facilitate sperm transfer
7
Q
Class Bivalva
A
- ex. Scallops, oysters, clams, mussels
- muscles & dorsal hinge hold shell together
- use sticky threads, muscular foot, or rapidly flapping shells
- adductor muscles to hold the valves together
- have gills, not lungs
- no radula
- gills also used for gas exchange
8
Q
Cephalopoda
A
- ex. Octopi, squid, cuttlefish, nautilus
- soft bodied
- head attached to single foot modified into tentacles (8+)
- complex eyes
- pen = internal shell
- nautilus has external shell
- no shell in octopi
9
Q
Key features of molluscs
A
- bilateral
- coelomates
- complete digestive tract
- unsegmented
- foot
- has mantle that secretes shell
- radula
10
Q
Movement
A
- foot
- flapping
- jet propulsion
11
Q
Respiration
A
- oxygen exchange in gills
- siphon pumps water to gills
- gas exchange through skin
12
Q
Feeding
A
- filter-feeders
- use radula or tentacles
13
Q
Reproduction
A
- snails & bivalves: external fertilization
- tentacled molluscs & some snails: internal
- some are hermaphrodites
14
Q
Internal circulation
A
- open circulatory system
- dorsal heart
