Animal Diversity Lecture 4

Big decrease, almost extinct

Late Permian

Big decrease

Late Cretaceous

Mollusca

polyplacophora, bilvalvia, gastropoda, cephalopoda

Chitons

polyplacophora

Clams, oysters, scallops, mussels

Bivalvia

abalone, limpets, conch, nudibranchs, snails, and slugs

Gastropoda

Squid, octopodes, nautilus, cuttlefish

Cephalopoda

mostly living in rocky shorelines, 8 overlapping calcareous plates

Polyplacophora

Radula includes

magnetite

marine and freshwater, 2 valves

bivalvia

Inside a bivalvia

more prominent muscles

Suck water

incurrent siphon

Live on the surface of the bottom

Epifaunal

Live under (within) the bottom

Infaunal

marine, freshwater, or terrestrial

gastropods

All marine, coleoidea, nautiloidea

cephalopoda

Cephalopod Ink

mostly melanin and mucous

silurian to cretaceous

ammonites

Important food source

Mollusca

Defense mechanisms for molluscs to protect their bodies from irritants

Pearl making

Some mollusca are 

invasive species