bivalves Flashcards
are bivalves geologically widespread?
yes
bivalve PHYLUM
MOLLUSCA
bivalve CLASS
bivalvia
do bivalves live in fresh or marine water
both
egs of modern bivalves
cockles clams scallops razor shells muscles
what is the most distinctive feature of a bivalve
equal sized shells
bivalve shell?
calcareous shell
is it symetrical
yes - equivalve
what is the umbo on a bivalve
area of most curvature marking point of first growth
what is the socket of a bivalve
depression which fits over cardinal teeth in the right valve
what are bivalve cardinal teeth
raised area which fits into sockets on right valve
this allows articulation of the valves
what does inequivalve mean
different sized valves
what is bivalve ligament
helps hold shell together
what are bivalve pallial sinus
indentation in pallial line
present only in genera with retractable siphons
what is the pallial line bivalve
marks the limit of attachment of the soft tissue
what is bivalve hinge line
plane of symmetry where two valves are joined together
what is bivalve commisure
line where 2 valves meet
what is inside a bivalve
mantle
what is the mantle (bivalve)
soft tissue inside the bivalve where shell is secreted
what is bivalve modes of life
benthonic vagrant
how do bivalves feed
they feed using siphons which extend towards the edge of the shell
what are the 2 types of siphons (bivalves)
inhalent or exhalent
what are inhalent siphons(bivalves)
brings in fresh water
what are exhalent siphons (bivalves)
removes waste water
how does bivalve open/close
adductor muscles contract to close shell
what is a muscle scar
where the muscles are attached
how do (vagrant) bivalves move
using a muscular foot
what is the mytilus type (Bivalve)
bysally attached
what is the bysuss (bivalve)
thread like structure that attaches bivalve to the substrate
what is mytillus (bivalve)
common muscle
how does (bivalve) byssus indicate environment and mode of life
strong and flexble byssus = high energy environment (littoral zone)
how does (bivalve) shell covered in periostractum indicate environment and mode of life
protect shell from acidic rainwater or river water
how does bivalve STRONG SHELL indicate environment and mode of life
prevent breakage i high energy environment
how does bivalve streamlined and unornamented shells indicate environment and mode of life
no sharp edge to damage itself or others in colony
protection against strong currents
how do large bivalve adductor muscles indicate environment and mode of life
hold valves tight together so they dont dry out at low tide - tidal environment
what is the ostrea type (bivalve)
cemented to substrate
what is ostrea
common oyster
where does cement in ostrea bivalve come from
secreted from mantle
what shape is ostrea
take on the shape of the hard substrate
which valve is bigger in ostrea (bivalve)
left valve
what is gryphaea bivalve
ancient free lying bivalve
which valve is bigger on gryphaea
left - convex and much larger to balance on soft substrate
curved to keep opening above sediment
