Download Mollusks Ch. 13, pgs. 364-368 Characteristics of Mollusks *Mollusks

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Mollusks Ch. 13, pgs. 364-368
Characteristics of Mollusks
*Mollusks have ____________________.
*Most mollusks live in water, but some live on land.
*Examples of mollusks are______________, ____________, and _____________.
General Body Plan
*All mollusks have a layer of tissue called the_____________.
*A ____________is thin layer of tissue that covers a mollusks body organs;
secretes the shell or protects the body of mollusks without shells.
*The shell is made up of several layers. The inside layer is the smoothest and
thickest layer of the shell.
*Between the soft body and the mantle is a space called the________________.
*The mantle cavity contains ___________-the organs in which carbon dioxide
from the mollusk is exchanged for oxygen in the water.
*Mollusks have an_____________________________, which means the organs in
which carbon dioxide from the mollusk is exchanged for oxygen in the water.
*Mollusks have a well developed head with a mouth and some sensory organs.
*On the underside of a mollusk is the ___________________, which is used for
movement.
Classification of Mollusks
*Three most common groups of mollusks are __________, __________,
and______________.
Gastropods
Gastropods Body Plan
*All Gastropods except for slugs have a ___________________.
*Many have a pair of tentacles with eyes at the tips.
*Gastropods use a____________—a tongue like organ with rows of teeth—to
obtain food.
Gastropod Characteristics
*Slugs and many snails are adapted to life on land.
*They move by the contractions of their__________________.
*Slugs and snails are most active at night or on cloudy days.
*Slugs are protected by a _____________while snails are protected by a _______.
*Slugs and land snails eat plant leaves and stems.
Bivalves
Bivalves Body Plan
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*_______________ are mollusks that have a hinged two-part shell joined by
strong muscles.
*Bivalves pull their shell closed by contracting powerful muscles near the hinge.
*To open the shell, they relax their muscles.
Bivalve Adaptations
*Bivalves are adapted to live in water.
*Clams burrow deep into the sand by moving their muscular foot.
*Mussels and oysters attach themselves with a strong thread or cement to a solid
surface. Scallops escape predators by rapidly opening and closing their shells.
Cephalopods
*Cephalopods are the most specialized and complex mollusks.
*Cephalopods include: ____________, ____________________, _____________,
and _______________________.
Cephalopods Body Plan
*The word cephalopod means “____________”.
-Cephalopods have a well developed head.
-Their foot is divided into many tentacles with strong suction cups or hooks
for capturing prey.
*Squids and octopi have a well-developed nervous system and large eyes.
*Unlike other mollusks, cephalopods have a____________________________.
-In a closed circulatory system, blood containing food and oxygen moves
through the body in a series of closed vessels.
Cephalopod Characteristics
*All cephalopods are___________.
*They feed on______________, _________________, ___________, and
_____________________________.
Cephalopod Propulsion
*All cephalopods live in the ocean and are adapted to swimming.
*Squid and other cephalopods have a __________________between
________________________and its_________________________.
*When a cephalopod tightens its muscular covering, water is forced out through
an opening near the head.
*The jet of water propels the cephalopod __________________and it moves
away quickly.
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Value of Mollusks
*Mollusks are used for food.
*Hermit crabs use empty mollusk shells for shelter.
*Mollusk shells are used for jewelry and decoration.
*Mollusk shells also provide information about the conditions in an ecosystem.
Mollusk Problems
*Land slugs and snails damage plants.
*Certain species of snails are host to human parasites.
*Shipworms make holes in submerged boats.
*Mollusks can filter bad bacteria. Eating these mollusks can cause food poisoning.