Phylum Mollusca
Text Pages 585-593
Fill in the table below using the text pages.
Define the following terms & include them in your table.
Radula
Foot
Shell
Visceral mass
Open circulatory system
Animal system
Meaning of name
Mantle
Gills
Gastropods
Stomach foot
Bivalves
2 shells
Cephalopods
Head foot
Snails, slugs, nudibranchs
Clams, oysters, scallops
Nautilus, squid, octopus
Feed with a tongue shaped
structure called a radula,
herbivores scrape algae off
rocks
Carnivores-drill through shells
of other molluscs
Foot contains mouth and other
structures associated with
feeding
Filter feeders
Use feathery gills to sift
food from the water
Use sharp jaws (beak)
to eat their prey
Foot contains mouth and
other structures
associated with feeding
Foot contains mouth and
other structures
associated with feeding
Example Organisms
Feeding
Aquatic molluscs such as snails, clams and octopi breathe by using gills located
in their mantle cavity. Gills are part of the visceral mass
Respiration
Land snails & slugs breathe by
Gills
using an adapted mantle cavity
that remains moist and folded.
Open circulatory system
Simple heart pumps blood into sinuses that bathe tissues
with blood
Internal Transport
Excretion
Gills
Closed circulatory
system- blood always
moves inside blood
vessels
Have a mouth and anus
Get rid of ammonia by using simple tube shaped organs called nephridia
Nephridia are part of the visceral mass
Animal system
Gastropods
Move and hunt
Have a Brain
Bivalves
Inactive
Burrow in mud
Have a simple nervous
system
Cephalopods
Brain is well developed
and may be able to
remember things
Glide on mucus (Gross!)
Or swim
Sessile
(although larvae can swim)
Scallops can move by
flapping shells
Jet propulsion- force
water through tube-like
siphon
Nervous Systems
(response)
Types of movement
Sea hares – squirt ink
Shells
Move quickly
Nudibranchs – have chemicals
Can release dark
Defence Mechanisms
in their bodies that are
Mantle is a tissue layer
coloured ink to confuse
poisonous or taste bad
that covers a mollusks body
predators
Mantle is a delicate tissue
like a cloak and secretes
Camouflage
layer that covers most of a
CaCO3 which makes the
mollusks body like a cloak.
shell
Male transfers a sperm
Release sperm and egg into water. They find each other
sac to the female and
by chance and grow into free swimming larvae
fertilization takes place
Reproduction
(trochophore larvae)
when the eggs of the
female mature.
Reproductive organs are part of the visceral mass
Reproductive organs are
part of the visceral
mass
We eat them
We eat them
We eat them
Get pearls from them
Human uses for the
animals
One thousand oysters must be opened to find one pearl.