mollusca Flashcards
mollusca in latin means what?
soft
what is the mantle formed of? what does is secrete?
dorsal epithelium
calcareous spicules or one or more shells
what do molluscs use for feeding?
radula. they scrape out a living
name type of organisms that are included in mollusca
- clams
- snails
- limpets
- tusk shells
- ammonites
- nautilus
- squid
- octopus
mollusks have a shell of calcium carbonate set in a _________ _______.
protein matrix
name the 3 layers of a shell
- periostracum (outer)
- prismatic (middle)
- nacreous (inner)
protrandrous
having male reproductive organs come to maturity before female in hermaphroditic organisms.
name the 5 classes of phylum mollusca
- polyplacaphora
- scaphopoda
- gastropoda
- bivalvia
- cephalopoda
polyplacophora;
- what type of organism?
- where do they live?
- how big can they get?
- chitons
- intertidal
- up to 30cm
what are the plates of a polyplacophore bordered by?
a thick girdle/mantle
where is the foot located on a polyplacophore?
entire ventral surface
how does a polyplacophore move?
pedal waves.
Class scaphopoda = latin?
boat foot.
tooth or tusk shells.
‘Dentalium’
name some features of a scaphopoda
- no heart
- sendentry
- opening at both ends
- no gills
- foot for burrowing
- head rudimentary
- radula present
Gastropoda means what in latin? what organisms does it include?
stomach foot
- snails
- sea slugs
- limpets
- slugs
- abalone
cephalopoda = what in latin?
what organisms does it include?
'head feet' -octopus -squid -cuttlefish ammonites -nautilus
Lottia alveus
eelgrass limpet. extinct now, once common on the east coast.
what are the defining characteristics of gastropoda?
- proteinaceous shield on the foot (operculum)
- planispiral shell
- visceral mass and nervous system become twister 90-180degree
what do gastropods exhibit during embryonic development, in regards to the visceral mass and nervous system becoming twisted?
torsion.
what percentage of molluscans are gastropods?
75-80%
2 types of body whorls
sinestral - left
dextral - right
pneumostome
lung, mouth
autotomy
self amputation. where an organism discards one or more of its own appendages.
-displayed in GASTROPODA
via what doe gastropods reproduce?
love darts
bivalves; cephalization
lacks it
what is the siphon made of in bivalves?
mantle tissue
what two feeding mechanisms are bivalves missing?
radula odontophore (supports radula)
name some predator avoidance techniques for bivalves
- swim
- bury
- thick shells
- closed shells
- high densities
- attach through byssal threads
what are the defining characteristics of Class cephalopoda?
1: shell divided by septa, with chambers connnected by the siphuncle
2: closed circulatory system (vs the rest with hemocoel)
3: foot modified to form flexible arms and siphon
4: ganglia fused to form a large brain encased in a cartilaginous cranium
hemocoel
circulation system. a cavity surrounding the heart.
what is unique about cephalopoda’s heart?
three hearts beat as one.
what are the two groups of cephalopoda divided by?
those with shell and those without. (nautilus)
what do cephalopoda use for movement?
jet propulsion
name five bioluminescence and adaptions of cephalopodas that make them unique.
photophores chromatophores crypsis ink vision
hectocotylus
modified third arm/tentacle in males used for fertilizing females. (cephalopoda)
nidamental gland
female cephalopoda, accessory gland made of lamellae and help secrete egg cases.
