Download Banana Slugs

Mollusks (“soft-bodied”)
Bivalves
“Two shells”
Clams, mussels,
scallops, oysters
Two shells
Simple brain
Gills
Ocean
Sexual reprod.
Filter food from
water
Anchored to sea
floor OR open and
close shells to
propel themselves
Gastropods
“Stomach foot”
Snails, slugs
One shell or none
Brain and sense
organs
Gills or lungs
Land, ocean,
freshwater
Sexual reprod.
Use radula to
scrape food
Slide on slime
Cephalopods
“Head foot”
Squid, octopus,
cuttlefish
Internal “shell”
Most advanced
mollusk brain and
sense organs
Gills
Ocean
Sexual reprod.
Beak-like radula
tears prey apart
Jet propulsion
Ink as a defense
Cuttlefish
Scallops
Banana Slugs
The Banana Slug (Ariolimax columbianus) is a gastropod found in the
Northwest United States. It travels on a muscular foot leaving a trail of slime,
which serves several purposes. They have a hump on their back, a radula with
27,000 teeth-like structures, and a mantle with a cavity.
The Banana Slug can grow up to 12 inches (26 centimeters) and is the
world's second largest slug. The coloration of the Banana Slug may be a bright
yellow, slate-green, or white with or without black spots.
Ariolimax columbianus
Banana Slug
One way that the slug can breathe is using a small lung. The slug can
also breathe through its skin so long as the skin remains moist for gas
exchange to take place.
Besides aiding in breathing, the slime has several other functions. One
function is protection. Some predators do not care for the taste of the slug's
slime. The slime makes it easier for the slug to crawl along the forest's floor.
During mating season, the slime contains a chemical, which other slugs
follow.
Slugs have both male and female reproductive organs. Normally,
slugs trade sperm with other slugs, but they can fertilize their own eggs. They
may lay 12 to 100 eggs at a time and up to 50 to 150 eggs each year. The eggs
are pearl-like in color and about the size of a person's pinky fingernail. The
eggs are laid in clusters under logs, rocks, and in the soil. Eggs are laid in the
early spring, late summer and early fall. Most adults die after laying eggs. The
eggs laid in the late summer or early fall may not hatch until spring. It takes
three to four weeks for the eggs to hatch.
Slugs may feast upon a variety of plants as well as fungi and
decomposing plants. The slugs use their radula to scrape food off the source.
The slugs may be preyed upon by snakes, ducks, geese, shrews, moles, beetles,
crows, and salamanders. Raccoons have a trick to deal with the slime; they will
roll the slug in dirt to coat the slime!
Slugs have a pair of tentacles, which
they use to gather information about their
environment. The pair of tentacles located
on the top of the head has a small black spot
at each tip. These tentacles are used to
detect lightness and darkness. Slugs prefer dark and moist areas. The
second pair of tentacles functions as a nose. These tentacles pick up smells
especially during mating season. Most of the food sources are located by using
both pairs of tentacles.
Banana slug
Snails
The Snail is a gastropod, a soft-bodied type of mollusk that is basically a head
with a flattened foot. The soft body is protected by a hard shell, which the snail
retreats into when alarmed. These invertebrates are found worldwide in the seas,
in fresh water, and in moist areas on land.
Locomotion: Snails move by crawling, swimming, or floating with currents. Land
snails crawl on the ground, creeping along on their large, flat foot; a special gland
in the foot secretes a slimy fluid that helps the snail move. The common garden
snail is the slowest moving animal; it can travel about 0.03 mph.
Anatomy: Snails range in size from 0.02 inch (less than a millimeter) long to over
30 inches long! The largest land snail is the Giant African Snail; it is over 15.5
inches long and weighs about 2 pounds.
Snails have two pairs of tentacles on the head. Land snails have a light-sensitive
eyespot located on each of the larger tentacles; water-dwelling snail eyespots are
at the base of the tentacles. The smaller pair of tentacles is used for the sense of
smell and the sense of touch.
Diet: Most snails eat living and decaying plants, but some are predators. They eat
using a radula, a rough tongue-like organ that has thousands of tiny teeth.
Predators of the Snail: Many animals eat snails, including birds, fish, frogs,
snakes, turtles, beetles (and other insects), and people.
Label the Land Snail: External Anatomy
Read the definitions; then label the land snail diagram below.
eyespots - located at the tips of the
long tentacles on land snails
foot - the soft, muscular part of the
snail that allows the snail to move
shell - the hard, spiral, protective
covering of the snail
mouth - on the underside of the head - it contains
the radula, a file-like tongue that breaks down the
snail's food
respiratory pore - a small hole in the side of the
body, used for breathing
tentacles - two long and two short sensory tentacles
on the upper surface of the snail's head
head - the front part of the snail,
containing the tentacles, eyes, and
mouth
Blue Ring Octopus
The Blue Ring Octopus is the most venomous octopus. This small mollusk
lives in warm, shallow reefs off the coast of Australia, New Guinea, Indonesia,
and the Philippines. It has a life span of about 1 1/2 years.
Anatomy: The Blue Ring Octopus has distinctive blue rings on its body and on
its eight arms. It is only about 8 in. with the tentacles spread wide. Like all
octopuses, if an arm is lost, it can be regenerated.
Diet: The Blue Ring Octopus hunts during the day. It eats invertebrates and
wounded fish. It hides in the reef, then catches prey with its arms, bites it with
its tough beak, and kills it by delivering a poison in its saliva. The poison is
strong enough to kill a human being.
Protection: The Blue Ring Octopus also defends itself using its poisons. Like
other octopuses, it lives in dens: spaces under rocks, cracks on the sea floor, or
holes it digs under large rocks. It piles rocks to block the front of its den. The
den protects the octopus from predators (like moray eels) and provides a place
to lay eggs and care for them (a mother octopus doesn't eat during the entire 1
to 2 months she is caring for her eggs). In order to escape predators, an octopus
can squirt black ink into the water, allowing the octopus to escape. The
octopus swims by spewing water from its body, a type of jet propulsion.
Squid
The Squid is an invertebrate (animal without a backbone) that swims in the
oceans. Squid are closely related to the octopus. Squid can change the color
of their skin to mimic their environment and hide from predators.
Squid are soft-bodied cephalopods. They move by squirting water from the
mantle through the siphon, using a type of jet propulsion. When in danger,
squid squirt a cloud of dark ink in order to confuse their attacker and allow the
squid to escape. Squid reproduce by releasing eggs and sperm into the water.
Anatomy: Squid range from 1 to 60 ft long. The biggest squid is the Giant
Squid. Squid have a large mantle and a large head (with a large brain), eight
arms with suckers, two longer feeding tentacles, a beak-like radula, two
large eyes, and two hearts. Their large eyes are very similar in structure to
people's eyes. They breathe using gills.
Diet: Squid eat fish, shrimp, and other squid. These fast-moving carnivores
(meat-eaters) catch prey with their two feeding tentacles, then hold the prey
with the eight arms and bite it into small pieces using a parrot-like beak. The
esophagus runs through the brain, so the food must be in small pieces before
swallowing!
Predators: Many animals prey upon squid, including many sharks and other
fish, some whales, squid, and people.
Label Squid External Anatomy Diagram
Using the definitions listed below, label the squid diagram.
arms (8) - eight short limbs, each of which has two rows of suction cups
on the lower side; the arms hold the food while the squid bites it into
swallowable pieces.
beak and mouth - the parrot-like beak on the mouth is used for biting
food into small pieces. The beak and mouth are surrounded by the bases of
the arms and tentacles.
clubs (2) - the ends of the tentacles, which have toothed suckers.
eye - an organ used to see; squids have two, very large eyes (they are large
in proportion to the size of the body).
feeding tentacles (2) - the two, long tentacles are used for obtaining
prey; they have toothed suckers only near the tip.
fins - two flaps on the mantle that are used to stabilize the squid during
swimming.
head - the small part of the body between the mantle and the arms; the
head contains the eyes, the brain, and the muscular buccal mass (which
crushes the food).
mantle - the large part of the squid in front of the head; inside the mantle
are the stomach, gills, ink sac, pen, reproductive organs, and many
digestive organs.
siphon - a tube-like organ on the lower side of the head; it expels water
forcefully, enabling the squid to propel itself through the sea.
Clams
Clams are animals that burrow under the sea floor. They are bivalves,
mollusks that have two shells that protect a soft body. There are over 15,000
different species of clams worldwide. The biggest clam is the Giant Clam,
which is up to 4.8 feet long and weighs up to 550 pounds. Most clams are only
a few inches long.
Anatomy and Diet: Clams come in many colors, including shades of brown,
red-brown, yellow, cream, etc. The two shells are attached by a muscular
hinge. When a clam is threatened, most clams will pull their soft body into into
the shells and close the shells tightly for protection. The foot is used to burrow
into the sand. Clams use their tube-like siphon to draw in water, from
which they filter oxygen and tiny particles of food.
Predators of the Clam: Many animals eat clams, including eels, starfish, and
people.