BIOL 101L Characteristics of Molluscs

what is the class of chiton?

polyplacophora

what is the class of clam?

- bivalvia

- two halves or two valves

what is the class of snail?

gastropoda

what is the class of squid?

cephalopoda

what is the habitat of chiton?

marine (rocky intertidal)

what is the habitat of clam?

marine and freshwater (sandy intertidal)

what is the habitat of snail?

- aquatic and terrestrial

- ocean, freshwater, and land

what is the habitat of squid?

marine (deep water)

what is the feeding behavior of chiton?

scavenger

what is the feeding behavior of clam?

filter feeder

what is the feeding behavior of snail?

aquatic and terrestrial

what is the feeding behavior of squid?

predatory

locomotion of chiton?

move very slowly

locomotion of clam?

burrows and sedentary

locomotion of snail?

mobile but slow

locomotion of squid

jet propulsion (fast)

radula of chiton

- stronger than a kitchen knife and used for scraping

radula of clam

not present/don't have one

radula of snail

- all have them

- rasping tongues

- allows them to scrape algae from the surface of rocks, walls of aquariums, and other shells in order to feed

- carnivorous organisms use their _______ to drill a hole into other mollusc shells in order to obtain their food

radula of squid

- don't have one

- have tentcles instead to catch prey while the arms hold prey so it can be eaten (mouth lies within the arms)

mantle of chiton

- have elongated, flattened bodies protected by segmented shells by the _______

mantle of clam

- secretes the shell, allowing the shell to grow as the internal organs grow

- fleshy part directly under the shell

foot of chiton

- large ventral ______

- can move rapidly for a mollusc

- will curl into a ball if disturbed

- can cling to rocks in intertidal zones

- _____ is strong and undulates (move with a smooth wavelike action) during movement

foot of clam

- is used as a burrowing mechanism and is blade like (sometimes called a hatchet)

- used to dig

foot of snail

- broad, used to creep

- mucus secretion helps aid locomotion by preventing injury to the _______

foot of squid

- fused with the head

- allows for more efficient swimming

shell of chiton

- segmented

- protects its elongated, flattened body

- strong and thick

shell of clam

- muscles keep the ______ closed and when the muscles relax, the _______ can open, allowing the foot to dig into the sand and the siphon to reach up into the water

shell of snail

- able to withdraw into _________ for protection

- wide variety of shapes, colors, and sizes

- most have an asymmetrical spiral _______

shell of squid

- no outer shell

- reduced and internalized

siphon of clam

- modification of the mantle

- one ________ filters food and water through the gills adn then into the mouth

- another _________ carries water away

siphon of squid

- used for locomotion

- muscular contractions force water through the _______ (funnel), propelling the organism through the water

- modification of the foot

what is a radula?

- a rasp-like structure in the mouth

- used for scraping algae adn drilling into hard shells of other molluscs

- seen in predatory gastropods

what is the mantle?

thin, fleshy layer that secretes a large shell

what is a siphon?

Used for water flow that is used sometimes for locomotion, feeding, respiration, and reproduction. It is found in all the Mollusca classes (particularly Bivalvia) and is part of the mantle; water flow is directed to or from the mantle cavity.

head-foot

Cephal = head

poda = foot

stomach-foot

gastro = stomach

poda = foot

torsion

- gastropods

- during development, the visceral mass and mantle rotate so that the anus ends up lying in the anterior body over the head and mouth

- gives the animal the ability to retract into the shell if in danger

what happens to the waste of gastropods after torsion occurs?

- wastes are then eliminated into water near the area where water is taken in for respiration

- risky adaptation because this can end up harming the animal

what do clams use gills for?

- respiration and feeding

- water is filtered in through the ________ and particles attach to mucus on the _________

- in freshwater, the ______ are important in protecting the larvae until they can be released (_______ function as brood chambers)

most clams are born _______ and then as they mature they may grow into ______

male; female

what is an operculum?

a cover in gastropods that closes to prevent drying out