1. PHYLUM MOLLUSCA

2. WHAT IS A MOLLUSK?
Why are animals that look and act so different grouped in the same phylum? It is because they share developmental patterns.

3. Characteristics of Mollusk
1. mantle
2. mantle cavity
3. shell
4. true coelom
5. head, muscular foot, visceral cavity
6. systems: circulatory, respiratory, digestive, excretory, reproductive, and nerve impulses

4. Mollusks are well defined as soft bodied animals that either have an
external or internal shell.
Their name comes from the Latin word molluscus meaning soft.

5. Most mollusks are composed of 4 basic parts:
foot - flat surface adapted for locomotion and usually contains the mouth and other feeding structures
mantle - covers most of the body and secretes the shell
shell - composed of calcium carbonate
visceral mass - contains the internal organ

6. Unique features of most mollusks include
Mantle
ctenidia - special gill which are also used for filter feeding
radula - rasping tongue-like structure used for scraping

7. the blood is not always contained in vessels. there are no veins.
INTERNAL TRANSPORT
OPEN CIRCULATORY SYSTEM
the blood is not always contained in vessels.
there are no veins.

8. What is a closed circulatory system?

9. Excretion -
All animals must remove waste products. An open circulatory system will work well for slow
moving animals. Why is an open circulatory system not adequate for fast-moving animal