mollusca Flashcards
what are the main characteristics of mollusca?
shell
gills and lungs
heart (within ceolum)
nervous system of ganglia
one foot
siphon
mantle
triploblast protosomes
bilateral symmetry
what is the scraping mouth part of molluscs called?
the radula
what are the classes of mollusca?
polyplacophora, gastropoda, bivalvia and cephalopoda
what class are chitons?
polyplacophora
are polyplacophora marine?
yes completely
how many plates compose the polyplacophoras shell?
8
do polyplacophora have ocelli
no
how do polyplacophora defend themselves
roll into ball
what class are snails, slugs and nudibranchs?
gastropoda
what are the characteristics of gastropoda?
univalved shells
torsion
bilateral symmetry
what is torsion?
gastropod’s visceral mass turning 180° during development where they technically lose bilateral symmetry but not really
what class includes squids ,octopus, cuttlefish and nautilus?
cephalopoda
what has been modified from molluscs in cephalopods?
molluscan foot into the tentacles
siphon (usually for breathing) into propulsion and respiration
do squid and cuttlefish have shell
yes but a reduced one
what are chromatophores?
specialised cells in cephalopod skin that change colour and texture for communication and cypris (hiding)
how complex are cephalopod eyes and brain and what are the qualities?
very complex, the eyes having retina, cornea and chambers and the nervous system being the largest of all invertebrates.
what animals are in bivalvia?
clams, mussels and scallops
what word is used to describe hinged shells?
bivalved
do bivalvia have gills or luNgs
yesssss they have gills
what is a mantle and its function?
a fleshy dorsal (on the upper side) wall that encloses the visceral mass of the animal
secretes the matrix upon which the calcium carbonate shell grows
can be modified for movement or feeding
can be water filled
