Download Mollusks Notes

WARM UP
1. List seven characteristics of
roundworms.
Mollusks Notes
Phylum Mollusca
General Characteristics
• Live in a
variety of
habitats
• Extreme
diversity
– About
100,000
species
– Six classes
Structure
• Mantle protects the
soft body and
secretes the shell
• Gills for gas exchange
• Visceral mass
contains the organs
• Muscular foot used
for movement
• Open circulatory
system
– Structures are bathed
in blood
Class Gastropoda
• “Belly foot”
• The largest class of
mollusks
– Snails, slugs, etc.
• Use a tongue-like radula
to scrape and tear food
Class Bivalvia
• Pelecypoda = “hatchet foot”
– Use foot for burrowing
• Clams, oysters , scallops
• Two part hinged shell
– Muscle to open and
close
• Filter feeders
– Use gills
– No distinct head or radula
Class Cephalopoda
– “Head foot”
– Squid , octopus,
nautilus, cuttlefish
– Adapted for active
predation
• Well-developed head,
eyes, and nervous
system
• Foot is modified into
tentacles
• Can move quickly by jet
propulsion
– High oxygen demand
– Closed circulatory
system
• Radula and jaws
WRAP UP
• Place each of the
pictures into the correct
Class of Phylum
Mollusca.
Choices are Bivalvia,
Scaphopoda, Polyplacophora,
Monoplacophora, Gastropoda,
Cephalopoda