PHYLUM MOLLUSCA Soft bodied Triploblastic Mouth and Anus True Coelum Bilaterally symmetrical Moist environments

Transcription

1 PHYLUM MOLLUSCA Soft bodied Triploblastic Mouth and Anus True Coelum Bilaterally symmetrical Moist environments ml

2 Mollusca Phylum Mollusca includes snails and slugs, oysters and clams, and octopuses and squids Most molluscs are marine, though some inhabit fresh water and some are terrestrial Molluscs are soft-bodied animals, most are protected by a hard shell Most molluscs have separate sexes with gonads located in the visceral mass Most have kidneys metanephridia

3 Three main parts that all Mollusca have: Muscular foot, a Visceral mass and a Mantle Most also have a water-filled mantle cavity, and feed using a rasplike radula Nephridium Visceral mass Heart Mantle Coelom Gonads Intestine Mantle cavity Anus Gill Stomach Shell Radula Mouth Foot Nerve cords Esophagus Mouth Radula Fig

4 Mollusca: Polyplacophora Class Polyplacophora consists of the chitons, oval-shaped marine animals encased in an armor of eight dorsal plates Marine only

5 Mollusca: Gastropods About three-quarters of all living species of molluscs are gastropods (a) land snail (b) sea slug

6 Mollusca: Gastropods Most gastropods are marine, but many are freshwater and terrestrial species Most have a single, spiraled shell Slugs lack a shell or have a reduced shell Banana slug courtship Each almost 10 inches long!

7 The most distinctive characteristic of gastropods is torsion, which causes the animal s anus and mantle to end up above its head Anus Mantle cavity Stomach Intestine Mouth Fig

8 Mollusca: Bivalves Molluscs of class Bivalvia include many species of clams, oysters, mussels, and scallops They have a shell divided into two halves The mantle cavity of a bivalve contains gills that are used for feeding as well as gas exchange Umbo The oldest part of the shell ridges show where mantle has laid down shell

9 Class Bivalvia - Anatomy Siphon Mouth Labial Palps Foot anus gills intestine

10 Zebra Mussels: Dreissena polymorpha Native to Asia, introduced to the North America in ballast water

11 Mollusca: Cephalopods Class Cephalopoda includes squids, octopuses, nautiluses and the extinct ammonites Cephalopods have a closed circulatory system, welldeveloped sense organs, and a complex brain Most octopuses creep along the sea floor in search of prey Octopus

12 Mollusca: Cephalopods Squids use their siphon to fire a jet of water, which allows them to swim very quickly

13 Mollusca: Cephalopods One small group of shelled cephalopods, the nautiluses, survives today Chambered nautilus

14 Mollusca: Giant Squid Monsters of the deep. Colossal Squid

15 Paul the octopus There was something about the way he looked at our visitors when they came close to the tank. It was so unusual, so we tried to find out what his special talents were Paul the Octopus predicts world winners

16 Expectations for Mollusca Lab 9 Go through Lab 9 in your lab book, identify all of the body parts and answer all of the questions. What are the key characteristics of each class of mollusca? Differentiate between the Gastropoda, Bivalvia and Cephalopoda. For this one, no quiz, just answer all of the lab book questions and show me your dissection prior to finishing!