WHO’S WHO?

GASTROPODS

SNAIL

BIVALVES

SCALLOP

CEPHALOPODS OCTOPUS

MOLLUSKS

BASIC CHARACTERISTICS

• BILATERAL SYMMETRY

• SOFT BODIES – MANY HAVE SHELLS FOR PROTECTION

• MANY HAVE A RADULA FOR FEEDING

(A RASPING TONGUE)

SNAIL’S MOUTH & RADULA

BASIC CHARACTERISTICS

• HEAD: CONTAINS THE BRAIN, EYES, MOUTH

• FOOT: MUSCULAR ORGAN USED FOR LOCOMOTION OR ATTACHMENT

• VISCERAL MASS: BODY AREA WHICH CONTAINS MAJOR ORGANS

• MANTLE: SPECIALIZED ORGAN WHICH MAKES THE CALCIUM CARBONATE SHELL & ADDS COLOR

BODY REGIONS OF COMMON MOLLUSKS

SHELL

VISCERAL MASS

MANTLE

FOOT SHELL

MANTLE

FOOT

FOOT

SHELL

MANTLE

VISCERAL MASS

VISCERAL MASS

CLASS: BIVALVES “TWO SHELLS”

BIVALVE CHARACTERISTICS • 2 SHELLS ARE CALLED VALVES

• ALL ARE FILTER FEEDERS – EAT PLANKTON

• CILIA CREATE A WATER CURRENT. AS WATER PASSES OVER THE GILLS, OXYGEN IS ABSORBED AND FOOD IS PASSED TO THE MOUTH.

Siphons

CLAMS • BURROWING/DIGGING ANIMALS

• EXTEND SIPHONS TO FEED ON PLANKTON, GET OXYGEN & RELEASE WASTES

• CLAMS USE A MUSCULAR FOOT TO DIG

COQUINAS

SIPHON

QUAHOG CLAM

RAZOR CLAM

SOFT SHELL CLAM

GIANT CLAMS

SIPHON

MUSSELS

• MOST ATTACH TO HARD SURFACES

• ATTACH TO OBJECTS WITH BYSSAL THREADS (STRONG FIBERS)

BYSSAL THREADS

RIBBED MUSSEL

BLUE MUSSEL

MUSSELS

MUSSELS FEEDING

OYSTERS

• ONE SHELL IS PERMANENTLY ATTACHED TO A HARD SURFACE (DO NOT BURROW)

• OYSTERS MAKE PEARLS! PEARLS ARE MADE WHEN A PARTICLE (SAND) GETS INTO THE SHELL & IRRITATES THE MANTLE.

IN RESPONSE THE MANTLE COVERS IT WITH A LAYER OF SHELL MATERIAL OVER & OVER & OVER AGAIN.

PEARLS

EASTERN OYSTER

PACIFIC OYSTER

EDIBLE OYSTER

OYSTERS ON ROCK

SCALLOPS

• MOBILE ANIMALS – CAN “SWIM” BY OPENING & CLOSING THEIR SHELLS RAPIDLY

• HAVE “EYES” ON THE MANTLE (LIGHT SENSITIVE)

“EYES”

BAY SCALLOP

“EYES”

BAY SCALLOP

“EYES”

SCALLOP GUTS

SCALLOPS

PINK SCALLOP

ROCK SCALLOP

KELP SCALLOP

DEEP-SEA SCALLOP

UP CLOSE & PERSONAL WITH A CLAM

EXCURRENT SIPHON (WATER,CO2,WASTES OUT)

INCURRENT SIPHON (WATER,O2,FOOD IN)

FOOT – FOR DIGGING

GROWTH LINES

SHELL SHELL

MANTLE MANTLE

GILLS GILLS

FOOT

INTESTINE

HEART

BLOOD VESSELS (CLOSED SYSTEM)

MUSCLE SCAR

MUSCLE SCAR

PALLIAL LINE

ADDUCTOR MUSCLE - HOLD SHELL CLOSED

GILLS FOOT

ADDUCTOR MUSCLE - HOLD SHELL CLOSED

HINGE LIGAMENT – HOLDS 2 SHELLS TOGETHER

MANTLE - MAKES SHELL

LABIAL PALPS BRING FOOD TO THE MOUTH

MOUTH

ESOPHAGUS

STOMACH

DIGESTIVE GLAND

INTESTINE

HEART

EXCURRENT SIPHON

INCURRENT SIPHON