Mollusca

What are the five general traits about molluscs?

Bilaterally symmetrical

Poorly Cephalised

Aquatic

Moves and grazes over a hard surface

Radula used in feeding

_______ symmetrical

____ Cephalised

__atic

Moves and grazes over a ___ surface

_____ used in feeding

A Radula is a ______ of teeth

A Radula is a conveyor belt of teeth

Can you name the 6 Clades of Mollusc?

Aplacophora

Polyplacophora

Bivalvia

Gastropoda

Scaphopoda

Cephalopoda

Give some features of the class Aplacophora

Covered by a cuticle with a calcareous scales/spicules embedded in itCovered by a ____ with a calcareous ___________ embedded in it

Poorly developed ____

Mixture of ______ and _______ features

_____ like molluscsWorm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Reduction of foot

Loss of radula and loss of gills

Aplacophora

Loss of ____ and loss of____

Reduction of ___

Worm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Covered by a cuticle with a calcareous scales/spicules embedded in it

Reduction of foot

Loss of radula and loss of gills

Worm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Covered by a cuticle with a calcareous scales/spicules embedded in it

Reduction of foot

Loss of radula and loss of gills

Worm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Covered by a cuticle with a calcareous scales/spicules embedded in it

Reduction of foot

Loss of radula and loss of gills

Worm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Covered by a cuticle with a calcareous scales/spicules embedded in it

Reduction of foot

Loss of radula and loss of gills

Worm like molluscs

Mixture of primitive and specialised features

Poorly developed head

Covered by a cuticle with a calcareous scales/spicules embedded in it

Reduction of foot

Loss of radula and loss of gills

Give some features of the class Polyplacophora

Highly adapted for ______ to rocks

No cephalic ___ or ______ , ___ indistinct

Multiple ___ and segmented ___ , but other body parts are not ________

PolyplacophoraHighly adapted for adhering to rocks

No cephalic eyes or tentacles, head indistinct

Multiple gills and segmented shells, but other body parts are not segmented

Shell is eight overlapping plates

Probably diverged early from the main line of molluscan evolution

Shell is ___ overlapping plates

Probably diverged ___ from the main line of molluscan evolution

Give some features of the class Bivalvia

BivalviaLaterally compressed

Shell of two hinged halves, encloses the body

Infaunal or epifaunal

Filter feeders

Water comes in through a siphon and food is extracted using the gills

Poorly cephalised

______ compressed

Shell of __ hinged halves, encloses the body

__faunal or __faunal

___ feeders

Water comes in through a ____ and food is extracted using the ___

____ cephalised

Give some features of the class Scaphopoda

ScaphopodaTusk or tooth shells

Elongated cylindrical tube, open at both ends

Burrowing marine molluscs

___ or ____ shells

Elongated _______ tube, ___ at both ends

_______ marine molluscs

Give some features of the class Gastropoda

Gastropoda30,000 species

Development of the head

Only terrestrial molluscs

Motile; foot used for crawling, burrowing or even swimming

Conversion of the shell to form a deep protective retreat

Torsion

_____ species

Development of the ____

Only _______ molluscs

Motile; foot used for ______, _______ or even _______

Conversion of the shell to form a deep _______ retreat

Torsion

Gills, anus, mantle cavity now located behind the head

TorsionTwisting of the body through 180 degrees counterclockwise

May alllow the withdrawal of the head into the shell before the foot

Torsion and spiraling of the shell are independent

Twisting of the body through 180 degrees ____________

___, ___, _____ cavity now located behind the head

May alllow the withdrawal of the ___ into the shell before the foot

Torsion and ______ of the shell are independent

Give some features of the class Cephalopoda

CephalopodaHead has prehensile tentacles and arms

Jet propulsion

Carnivorous

Majority 6-70cm

Giant deep sea squid Architeuthis <16m (body 4m circumference, 6m long tentacles)

Head has prehensile ______ and ____

__ propulsion

___ivorous

Majority ___cm

_______________Architeuthis <16m (body 4m circumference, 6m long tentacles)

Cephalopod

Polyplacophora

Aplacophora

Gastropod

Scaphopod

Bivalvia

Polyplacophora

Cephalopod

Gastropod