Mollusks Notes
Three Classes of Mollusks
1. Class Gastropoda –
2. Class Bivalvia –
3. Class Cephalopoda –
Basic information
1. Over _________ living species
2.
3.
Body Plan
•
Divided into two regions:
1.
2.
Head/foot
•
______(contains mouth and variety of
sensory structures)
•
_________ (muscular organ used for
Locomotion)
1
Visceral Mass
1.
2.
3.
4.
Mantle
1.
2.
mantle cavity
1.
2.
nervous system
•
__________: paired cluster of nerve cells
1.
2.
3.
2
Feeding
•
_______________: flexible, tongue like strip of tissue covered with tough
abrasive teeth that point backward
Feature
Gastropoda
Bivalvia
Cephalopoda
External Shell
Head
Radula
Locomotion
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Class Gastropoda
•
Most diverse class of mollusks
•
90,000 species
•
Snails, abalones, conches= single shell
•
Slugs = no shell
Torsion
•
__________________ twists around 180° in
relation to the head
•
Twisting results in mantle cavity, gills, and anus
to the front of the animal
•
Gastropod is now able to with
_________________________ when threatened
Movement
•
foot secrets a substance allowing animal to glide over surfaces (Slime Trail)
Open Circulatory System
•
______________ (blood in an organism with open
circulation) does not remain in vessels
1. Collected from gills or lungs
2. Pumped through heart
3. Released directly into ________________
a) Fluid filled spaces or blood cavity
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Bivalvia: Clams Notes
Characteristics
1.
2.
3.
4.
5.
Anatomy of Valves
•
Shell is divided into two halves (_____________)
•
Connected by a ______________
•
_______________
–
Contract: _______________
–
Relax: _________________
Clam Sensory information
•
3 pairs of ganglia
–
mouth (______________)
–
digestive system (__________)
–
Foot (____________)
Foot
_________ helps burrow in the sand or mud
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Water Flow
water enters through _______________________
Water exits through _____________________
Steps in digestion: Filter Feeders
1. ___________ in gills set up water current
2. ______________ for small organisms
3. ___________: flaplike structures that surround & guide food into the clam's
mouth
4. Food then enters the mouth
5. Stomach: ______________________
6. _______________: digested particles are absorbed
7. _______________: collects and removes digestive wastes
8. Waste are passed through the ______________________
Function of Gills
1.
2.
6
Growth Rate
_____________oldest part of the clam
Growth rings_________________
CLASS CEPHALOPODA: Most advanced class
Head-foot
•
foot is concentrated in the _______ region
•
foot is modified into ___________________ equipped with ____________
•
Foot also forms _________________ for expelling water, allowing movement by
"jet propulsion"
What two features can a squid have on its suction cups?
What are these structures used for?
How do the following cephalopods move:
Squid:
Octopi:
Squid
Octopi
# of tentacles
# arms
Suction cups present
Sucker rings or hooks
present on suction cups?
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Why would an octopus or squid release ink?
_______________– pigment cells that expand and contract to produce color
change.
–
Used as danger signals, protective coloring, and for courtship.
What do cephalopods eat?
Which cephalopods contain poison in their saliva?
What type of circulatory system doe cephalopods have?
What is a closed circulatory system?
____________ delivers ___________________ directly to organs through veins and
arteries
Do octopi and squids have cephalization?
Reproduction
1. Male or Female
2. The male uses __________ to take sperm from own ___________ and insert into
females __________________
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3. The female lays ~100 eggs and guards them until they hatch (approx 50 days)
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