Class Gastropoda
The Univalves
Zoology
Class Gastropoda
 Class Gastropoda is the
largest and most diverse
group of mollusk.
 Over 70,000 living
gastropod species are
still currently found on
earth today. Over
15, 000 fossil species
have been discovered.
Class Gastropoda
 Class Gastropoda
includes snails,
limpets, slugs_,
whelks, conchs,
periwinkles, sea
slugs, sea hares, and
sea butterflies.
Gastropod Homes
 Gastropods live in
aquatic and
terrestrial
environments.
Gastropods that live
on land have
adapted an area in
their mantle into a
lung so that they can
breathe out of water.
Univalves
 Gastropods are
univalves, which means
that they have one shell.
 The shell is made of one
piece and may be coiled
or uncoiled.
 The apex, or center of
the shell is the oldest
part of the shell.
 The spirals on the shell
are called whorls.
Whorls may curl to the
right or left depending on
the genetic makeup of
the gastropod.
Gastropod Bodies and
Torsion
 Gastropods are primarily
bilaterally symmetrical.
 However, the middle part
of their body is
asymmetrical because of
torsion, which is a
process that twists the
mantle cavity 180
degrees relative to the
head and foot.
 Gastropods are the only
mollusk that undergo
torsion.
Gastropod Defense
 Gastropods defend
themselves by two
primary ways: their shell
and their mucus.
 Gastropods also have
symbiotic relationships
with some Cnidarians.
In some cases, the
gastropod can control
the Cnidarian’s stinging
tentacles to defend
against predators.
The Gastropod Diet
 Gastropods are primarily
grazers. They are
primary consumers in
their ecosystem because
they feed on plants.
They use their radula,
which is a combination
of a tongue and teeth, to
cut and scrape food.
Pesky Little Pests
 Gastropods are a
garden pest because
they often eat
landscaping plants
and their population
can be hard to
control through
conventional
pesticides.
Salt and Snails….
 Snails lose the water
in their bodies
through the diffusion
of water, or osmosis,
when salt is poured
on their body. Water
leaves the body cells
of the snail to
balance the salty
environment.