Class Bivalvia• Bivalve mollusks

have two shells (valves).

• Use muscles to close valves

• Mussels, clams, oysters, scallops, shipworms

• Mostly filter feeders

• No head or radula

Class Bivalvia• Scallops have a row of small blue

eyes along the mantle edge

Class Bivalvia• Like other mollusks, bivalves have

an open circulatory system.• They breathe and filter feed

through gills

Class Bivalvia• Incurrent and

excurrent siphons are used to pump water through the organism for:

1. Gas (O2) exchange

2. Filter feeding3. Jet propulsion

Class Bivalvia - Locomotion

• Bivalves move around by extending the muscular foot between the shells.

• Scallops swim by clapping their shells together to create jet propulsion.

• Can secrete sticky byssal threads to attach to rocks & other surfaces

http://www.youtube.com/watch?v=u_RfgvIETEY&feature=related

http://www.youtube.com/watch?v=vmi_I8QW5eo

Oysters produce pearls

• https://www.youtube.com/watch?v=T18E58vOTus

• Oysters secrete shiny layer of calcium carbonate to coat irritating particles or parasites