Transcript Mollusks

Mollusk Discussion
June 2, 2016
Classification
Kingdom: Animalia
 Phylum: Mollusca

Basic Characteristics
1.
2.
A mollusk is another name for a
shellfish.
Some shellfish live on land and not all of
them have shells.
Basic Characteristics (cont.)
3.
There are three major classes of shellfish:
a. Pelecypoda (Hatchet-footed) - These live inside
of two shells that are connected by a muscular
hinge which can open and close the shell. They
are referred to as bivalves. They are filterfeeders.
1. Examples: Clams, scallops, oysters and mussels.
b.
Gastropoda (Belly-foooted) - These have
just one spiral shell and carry their shells
on their backs. They are called univalves
and are mostly herbivores.
1. Examples: snail, slug, periwinkle and conch.
c.
Cephalopoda (Head-footed) - These have a
definite head surrounded by tentacles.
These are carnivorous.
1. Examples: squid, octopus, cuttlefish and
nautiluses
Mollusk Systems

Muscular-Skeletal
◦ Can have an outer shell
◦ Have an outer cover
called the mantle
◦ Have a muscular foot
that uses to move

Digestion
◦ Food brought in through
a siphon system and then
to its mouth
◦ Food goes to a digestive
gland and to its intestine
◦ Wastes leave via the anus
Mollusk Systems

Nervous
◦ Consists a series of ganglia
that conduct impulses.

Circulatory
◦ Have a 3-chamber heart,
blood and blood vessels
Mollusk Systems

Respiration
◦ Have tubes called siphons
that bring water in & out
of their bodies to deliver
oxygen & expel CO2
◦ Gills help with this

Reproduction
◦ Are either male or female
and reproduce sexually
with a large organ called a
gonad
Mollusk Systems

Excretory
◦ Have an excretory system
with an anus
◦ Have nephridium that get
rid of wastes

Symmetry
◦ Bilateral

Appearance
◦ Have a soft, thick, fleshy
body
◦ Can be very small or as
big as 6 ft across