M ollusca Bivalvia

Mollusca Bivalvia

• Class Bivalvia• Formerly known as Pelecypoda• There are more than 15 thousand species of:– Mussels– Oysters– Scallops– Clams– Numerous other families of shells

Introduction

Characteristics

• All shells have two pieces known as valves• In most, valves are similar size. • Shells vary greatly in size, color, and

ornamentation • The foot of bivalves is adapted for

burrowing in all species, except for the sedentary ones

• Some use the foot to hop from place to place

• Some have siphons Most have single pair of large gills

Used for respirationUsed for trapping food particles

Giant Clam

• Freshwater mussels can be less than .1 inches

• Giant clam shell can exceed 4 feet in length• 582 pounds• Can live up to 40 years

Fresh Water Mussels

Feeding• Filter Feeders & how they work• Plankton, larvae, eggs and detritus• Modern issues in filter feeding– Susceptibility to harmful pollutants– Algal blooming– Effects on humans

Making Pearls !• All bivalves make pearls• Sand gets embedded in the mantle• Secretion of aragonite and conchiolin

Evolution• Development of simple eyes in swimming bivalves– After the ability to swim

• Ability to burrow – Foot– sihpons

• No need to develop a head • Evolution of their shell• Scallop video

References • Elevel, Martina. "Mussels and Clams (Bivalvia)." Bivalvia. N.p., n.d. Web. 26 Mar.

2014. <http://www.molluscs.at/bivalvia/index.html?/bivalvia/main.html>.• Morton, Brian. "Food and Feeding." Encyclopedia Britannica Online. Encyclopedia

Britannica, n.d. Web. 26 Mar. 2014. <http://www.britannica.com/EBchecked/topic/67293/bivalve/35739/Food-and-feeding>.

• "Water Encyclopedia." Bivalves. N.p., n.d. Web. 26 Mar. 2014. http://www.waterencyclopedia.com/Bi-Ca/Bivalves.html

• "Mollusks." Mollusks. N.p., n.d. Web. 26 Mar. 2014. <http://www.mbgnet.net/salt/oceans/animals/mollusk.htm>.

• Madrigal, Alexis C. "Did You Know Scallops Have *Eyes*? Me Neither, but Look." The Atlantic. Atlantic Media Company, 28 Mar. 2013. Web. 01 Apr. 2014. <http://www.theatlantic.com/technology/archive/2013/03/did-you-know-scallops-have-eyes-me-neither-but-look/274469/>.