Mollusks and Annelids

BIOL 1407

Phylum Mollusca

• Chitons

• Gastropods – snails, slugs

• Bivalves – clams, oysters, scallops

• Cephalopods – chambered nautilus, squid, cuttlefish, octopus

Chitons

Gastropods

Photo Credit for Slug: Dr. Stephen Bostic, 2008

Video: Click on “Mating Leopard Slugs”http://www.bbc.co.uk/sn/tvradio/programmes/lifeintheundergrowth/video.shtml

Gastropods

Photo Credit for Florida Fighting Conch: LA Dawson, 2006, Wikimedia Commons

Bivalves

Photo Credit for Giant Clam: Jan Derk, 2002, Wikimedia Commons

Cephalopods

Video with Octopus and Cuttlefish: Start at 1:20 minutes http://www.youtube.com/watch?v=zC0zOLqYnRg&feature=related

Chambered Nautilus Photo Credit for Octopus: Albert Kok, 2007, Wikimedia Commons

Cephalopods

Photo Credit for Flamboyant Cuttlefish: Jenny Huang, 2006, FlickrPhoto Credit for Caribbean Reef Squids: Clark Anderson, 2006, Wikimedia Commons

Characteristics of Mollusks

• Bilateral symmetry• Triploblastic• Coelomate• Trochophore larva• Photo Credit for Lined Chiton: Kirt L. Onthank,

2007, Wikimedia Commons

Characteristics of Mollusks

• Shells (exoskeleton)

• Mantle• Visceral Mass• Foot• Photo Credit for Common Snail:

Macrophile, 2005, Wikimedia Commons

Characteristics of Mollusks

• Radula (many)• Video:

http://www.youtube.com/watch?v=BMOSvz5mThM&NR=1

• Video: http://www.teara.govt.nz/EarthSeaAndSky/SeaLife/Shellfish/2/ENZ-Resources/Standard/2/en

• Photo Credit for Gray Garden Slug Radula, TM400x: Michal Maňas, 2005, Wikimedia Commons

Characteristics of Mollusks

• Complete Digestive System

• Circulatory System: open or closed

• Gills• Centralized nervous

system• Photo Credit for Nudibranch: Jans Petersen,

2006, Wikimedia Commons

Intelligence

• Cephalopods– Complex Brains– Excellent Vision– Nervous System

controls Chromatophores

– Video, Kings of Camouflage: http://www.youtube.com/watch?v=2x-8v1mxpR0

• Photo Credit: Nick Hobgood, 2006, Wikimedia Commons

Centralized Nervous System

Phylum Annelida

• Segmented Worms

• Oligochaetes – earthworms & relatives

• Polychaetes

• Leeches

Oligochaetes

Photo Credit of earthworm : Michael Linnenbach, 2005, Wikimedia Commons

Polychaetes

Photo Credit of Christmas Tree Worms : Nick Hobgood, 2005, Wikimedia Commons

Leeches

Characteristics of Annelids

• Bilateral Symmetry

• Triploblastic• Coelomate• Segmented• Trochophore

larvae• Photo Credit of Tomopteris: Courtesy

of uwe kils, 2005, Wikimedia Commons

Annelid Videos

• Giant Earthworm Video: http://www.youtube.com/watch?v=DZig6EL5B6A

• Leech Video from Science Now: – Short Version (podcast):

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

– Long Version with graphic surgery: http://www.pbs.org/wgbh/nova/sciencenow/0305/01.html

• (Warning: bloody pictures)

Incomplete vs. CompleteDigestive Systems

Animal Nutrition• Macronutrients:

– Carbohydrates– Lipids– Proteins

• Essential Nutrients– Essential Amino Acids– Essential Fatty Acids– Vitamins– Minerals

Transport

• Closed Circulatory System

• Hearts = Pumps• Blood Vessels = Pipes

– Arteries– Capillaries– Veins

• Blood = Fluid• Photo Credit: Dr. Stephen Bostic, 2008

Gas Exchange

• Gills or Skin Surface• Respiratory Pigments

– Hemoglobin; Dissolved in blood (most common)

– Chlorocruorin (some polychaetes)

– Hemerythrin (some polychaetes)

– Photo Credit for Terebellid Polychaete: Matthias Buschmann, 2007, Wikimedia Commons

Excretory System: Metanephridia

Centralized Nervous System

The End

Unless otherwise specified, all images in this presentation came from:

Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.