Molluscs Flashcards
Phylum _____:
200,000 species
– More species in ocean than any other animal group
• Soft body enclosed by calcium carbonate shell
• Body covered by mantle
Mollusca
Mollusca :
Displays ____ Symmetry
uses ______ for locomotion
Bilateral
ventral muscular foot
The body of mollusca is covered by a Thin layer of tissue that secretes the shell called____.
mantle
Some Mollusks have ____ which is:
– Ribbon of small teeth used to rasp food from
surfaces
– Made of chitin
-has a chisel-like design
radula
is a coiled mass of vital organs wrapped
in a dorsal shell.
Mollusc
Name three classes of mollusca
- Gastropod
- Bivalvia
- Cephalopoda
known as stomach foot and are the most common mollusks.
•Snails, limpets, abalone, and nudibranchs.
•75,000 spp.
Class Gastropod
What kind of Gastropod has???
– No shell
– Colorful branches of the gut and gills
– Prey on sponges and other invertebrates
Produce noxious chemicals or retain undischarged nematocysts
taken undigested from prey
Nudibranchs (sea slugs)
Class _____:
• Clams, mussels, and oysters
• Body laterally compressed and enclosed with two parts
(valves)
• No head or radula
• Gills expanded and folded used to obtain oxygen, and filter
and sort food particles from water
Bivalvia
Clams burrow in sand or mud and water drawn in
and out of mantle by ____ which allow clam to feed and obtain oxygen while buried
siphons
Mussels secrete ___ that attach them to
rocks and other surfaces
byssal threads
____ cement their left shell to hard
surface and other to another; they also produce pearls
Oysters
______ bores in mangroves, driftwood, and
pilings
– Have symbiotic relationship w/ bacteria in the gut that
digests wood
– Valves lie at the inner end of tunnel lined w/ calcium
carbonate and siphon protrudes from entrance
– _______ = settles on bottoms of boats, pilings,
and other submerged surfaces
Shipworm; Fouling organism
Class _____ (head footed)
• Predators specialized in locomotion
• Octopi, squid, and cuttlefish
• Agile swimmers w/ complex nervous system and reduction
or loss of shell
• All are marine
Cephalopoda
What class have…??
• Large eyes on side of head
• Thick muscular mantle which protects head
• Water enters mantel and leaves through siphon =______
Cephalopod; jet propulsion
What kind of Cephalopod??
– Eight long arms (2 in to 30 feet)
– Bottom dwellers that live in crevices, bottles, etc
– Have beak-like jaws and radula to rasp flesh and secrete
paralyzing substance
– Distract predators with dark fluid from ink sac
Octopi
What kind of cephalopod???
– Two triangular fins on mantle – better swimmers than
octopi
– Can remain motionless, move forward, or backward
– Eight arms and two tentacles, all with suckers
– Has pen in upper surface of mantle
– Few cm to 60 feet!!
Squid
What kind of cephalopod??
– Eight arms and two tentacles, but body flatten w/ fin
running along the body
– Have calcified internal shell aids in buoyancy
Cuttlefish
What kind of cephalopod??
– Coiled external shell containing gas filled chambers
serves as buoyancy organ
– Has suckerless tentacles
Chambered Nautilus
_______ (class Polyplacophora – bearer of many plates)
– All marine
– Eight overlapping shell plates covering dorsal surface
– Live in shallow hard bottoms
– Have radula to rasp algae
Chitons
_____ or _____ (class Scaphopoda)
– Elongated shell tapered at end resembling elephant tusk
– Sandy muddy bottoms in deep water
– Many species have thin tentacles to capture small prey
Tusk shells or scaphopods
Which classes posses a ganglia??
Gastropods and bivalves
What class ???
– Most complex of invertebrates
– Brains coordinate and store information
– Complex eye reflects development
– Octopi and cuttlefish can learn
Cephalopods
What class display rapid color change coordinated with behaviors
and moods, from sexual display to camouflage
Cephalopods
Cephalopods – modified arm to transfer _____
spermatophore
