1. Mollusks

2. Evolutionary Advancement: The Coelom (true body cavity)
Definition: Mollusks are invertebrates with a soft, unsegmented body often enclosed in a hard shell
Evolutionary Advancement:
The Coelom (true body cavity)
Enables the muscles to be separated from the gut so that digestion of food is not hindered by muscle contraction for movement
A coelom provides a space where the circulatory system can transport blood

3. Class: Gastropoda

4. Characteristics: Most gastropods have a single shell, a head, and are motile.
Conch; conch fritters – blowing conch

5. Respiration occurs by gas exchange through the lining of the mantle cavity – must be kept moist. Avoids dessication by retreating into shell and sealing it off with a mucous plug. Radula, ribbon like membrane with tiny teeth pointing backwards – allows food to be chewed before eaten

6. Slug – gastropod without a shell
Slug – gastropod without a shell. Aquatic gastropods have gills within their mantle.

7. Class: Bivalvia
scallop

8. Giant clam
Characteristics: Most bivalves have two shells, no head, and are sessile.

9. Bivalves use siphons to feed
Reproduction: sexual like sponges, release sperm and egg into water

10. Class: Cephalopoda

11. Characteristics: Most cephalopods have no shell, a head, and are rapid swimmers.
Cuttlefish

12. Closed circulatory system

13. jaws on mouth of octopus

14. Largest brain of any invertebrate

15. Giant squid in battle with a baby sperm whale as described by fisherman in The squid won. Giant squid is largest invertebrate known (over 25 feet).