1. The “soft bodied” animals
Mollusks
The “soft bodied” animals

2. Characteristics
Visceral Mass- contains the organs- the “soft bodied” part
Mantle- makes a shell in most organisms.
Foot- muscular lower part used for movement
Shell in most
Radula - tongue-like structure, sharp
Head area- that contains the brain and sense organs
Systems: digestive, muscle, nervous, circulatory, reproductive, respiratory (gills)

3. Examples
Gastropod (also called univalves)- “stomach-foot”-- looks like the crawl on their “stomach”
Open circulatory system
Snails Slugs

4. Examples Bivalves- “two door ways”- Have 2 parts to their shell
Open circulatory system
Yellow nudibranch Giant clam

5. Examples Cephalopods- the “head-footed” mollusks
Closed circulatory system
Most advanced nervous system (they can learn!)
Atlantic squid Octopus Nautilus

6. Digestive system
Food enters through the mouth and goes through the esophagus, to the stomach, and then intestines. Wastes leave through the anus.

7. Respiratory system

8. Nervous system and sense structures
Gastropods: eye spots (on stalks at base of tentacles or on tentacles) and chemical sensors in tentacles
Bivalves: photoreceptor and vibration cells
Cephalopods: Best developed brain of all invertebrates- can detect light, vibrations, chemicals
Eye of snail suckers on octopus tentacles

9. Muscle system
The muscular foot
Gastropods Bivalves Cephalopod

10. Mollusk defenses Changing color.
Cephalopods have an amazing ability to change color very rapidly.
Chromatophores, pigment-filled bags, are found in the skin and expand and contract to reveal or conceal small dots of color.