PHYLUM MOLLUSCA Flashcards
Where are molluscs typically found?
All major environment:
- marine (all classes)
- fresh water (gastropods & bivalves)
- terrestrial (gastropods)
Describe the body plan of the phylum Mollusca.
Body has four largely independent regions:
- mantle (often w/ a shell)
- head
- foot
- viscera
Has 2 unique functionally important traits:
- ctenidium (gill) and radula
Describe the mantle found in the Phylum Mollusca.
Tissue layer that covers most or all of the body
How are new shells formed in molluscs?
The mantle adds new shell by accretionary growth at the edge of a tapered tube
Describe the mantle cavity found in molluscs.
Supports many functions: - respiration (all) - Feeding (some) - locomotion (some) - brood chamber (some) Different forms in different taxa Has unique ciliated gill bipectinate ctenidium(one to many depending on taxon)
What is the function of bipectinate ctenidium?
A unique ciliated gill that pumps water and plays an important role in suspesion feeding in some groups
What is the function of the radula?
Feeding structure
Flexible ribbon studded with many rows of chitinous teeth
Describe the two fluid-filled cavity that lie within the mesoderm.
Coelom: arise via schizocoely and is greatly reduced (only surrounds heart, gonad, kidney)
Hemocoel: extensive, blood is pumped by heart through vessels to spongy tissus
- fxn as circulatory system and hydraulic skeleton