Unit 7 Flashcards
What does Mollusca mean in English?
Soft
How many species of molluscs are there?
85,000
Do all molluscs have a radula?
No
What makes the shells of molluscs and what is the material of the shell made out of?
Made using the Mantle-Material is CaCO3
What are some common shared characteristics between molluscs?
Mantle-Mantle Cavity-Foot-Radula-Open Circulatory System MMFRO
Define Mantle
Muscular bag that surrounds the gills and most organs and is used to circulate water.
Define Mantle Cavity
The open internal space surrounded by the mantle (contains the guts).
Define Foot
Muscular structure used for movement.
Define Radula
Used to scrap up food, modified to bore holes in the shells, and form separate poison darts.
Define Open Circulatory System
Hemolymph (general body fluid that bathes organs) dumped on organs; cephlapods are the only molluscs that don’t have an open circulatory system.
What are the Molluscan Classes?
Polyplacophora-Gastropoda-Bivalvia-Cephalopoda PGBC
What are examples of Polyplacophora?
Chiton PC
What are examples of Gastropoda?
Snails-Nudibranchs G-SN
What are examples of Cephalopods?
Octopus-Squid C-OS
What are examples of Bivalves?
Clams-Mussels B-CM
Do Bivalves have a radula?
No
Define Shell
Valves
Define Muscles
Two muscles close to the shell: the posterior and the anterior adductor; the muscles pull the shells together to defend themselves from predators.
Define Circulation and Gas Exchange
Water comes in through the incurrent siphon, goes over gills, exits through the excurrent siphons; oxygen in the water goes to the clam and CO2 from the clam goes into the water.
Define Reproduction
Marine mussels release sperm and egg in the water.
Define Digestion
Most bivalves are suspension feeders, trapping fine mucus that coat the gills; they’re sessile and wait for food to come for them.
Where do Bivalves live?
Rocky Intertidal Zones- Sandy/Muddy Beaches
What eats bivalves?
Birds-Walrus-Sea Star-Sea Otter BWSS
How do oysters make pearls?
Made from nacres, a chemical made in all bivalves; a pearl is the result of having something that irritates the insides of oysters.
Define Shells of Gastropods
Spiral pattern-Made from CaCO3
Define Nervous System and Senses of Gastropods
Complex nervous system that can detect light, chemicals in water (rhinophores)
Define Defenses in Gastropods
Aposematic: most brightly colored to ward off predators; hard shell, toxins for killing prey, cerata in nudbranch have nematocysts.
Define Digestive Systems in Gastropods
Complete Digestive system w/ mouth and anus and a radula.
What habitats to Gastropods live in?
Tropical and Cold Waters- Sandy and Muddy Beaches
What is the difference between arms and tentacles?
Arms have suction cups all over but tentacles only have suction cups on the end.
How do Cephalopods move?
Jet Propulsion
Define Jet Propulsion
Filling body cavities with water and forcefully squirting it out to propel forwards and backwards.
List some characteristics of octopuses.
8 Arms
9 Brains
No Shell
List some characteristics of Squid.
8 Arms
2 Longer Tentacles
Internal Shell
Include largest invertebrate
List some characteristics of Cuttlefish
8 Arms
2 Tentacles
Internal Shell
List some characteristics of Nautiluses
External Shell
Can have as many as 90 arms
No suckers or hooks, but can hold prey w/ sticky secretion.
What are chromatophores?
Color changing cells.
Define Ink
Ink is made of a chemical named melanin; octopus, squid, and cuttlefish release ink from their siphons.
Define Benthic
Occurring on the bottom of a body of water.
Define Pelagic
Inhabiting the upper layers of the water.
