Biodiversity- Mollusks Sarah Whitebloom Matt Jones Eddie Frere

What are the 3 types of mollusks? Objective: SWBAT describe what a mollusk is, the different types of mollusks, examples, and their functions Warm-Up What is a mollusk? What are the 3 types of mollusks? An invertebrate with a soft, unsegmented body often enclosed in a hard shell containing calcium carbonate Gastropoda, Bivalvia, Cephalopoda

Notes- Mollusks Mollusk- an invertebrate with a soft, unsegmented body often enclosed in a hard shell containing calcium carbonate The body is divided into 4parts: foot, visceral mass, mantle, and shell

The 4 types Foot: it has different forms for different circumstances; flat structures for crawling, spade-shaped structures for burrowing, and tentacles for capturing prey Visceral mass: below the mantle; consists of the internal organs Mantle: thin layer of tissue that covers most of the body Shell: made by glands in the mantle that secrete calcium carbonate(not found on all slugs and other mollusk groups)

The Body

Feeding Can be herbivores, carnivores, filter feeders, detritivores, or parasites Snails and slugs get their food using a flexible, tongue-shaped structure called the radula There are hundreds of tiny teeth attached to the radula Herbivores use it to scrape the algae off the rocks Carnivores use it to drill through shells of other animals Food is carried by water which enters through a siphon: a tube-like structure where water enters and leaves the body

Circulation The oxygen and nutrients are carried through the mollusk body by a circulatory system It is either open or closed Open circulatory system: blood is pumped through vessels by a heart Open circulatory systems work best for slow-moving mollusks because the demand for oxygen is lower Closed circulatory system: transport blood through an animal’s body much more quickly than an open circulatory system; better for faster- moving mollusks

Gastropods Shell-less or single-shelled mollusks that move by using a muscular foot located on the ventral side Includes pond snails, land slugs, sea butterflies, sea hares, limpets, and nudibranchs

Bivalves Two shells that are held together by one or two powerful muscles Includes clams, oysters, mussels, and scallops

Cephalopods Soft-bodied mollusks in which the head is attached to a single foot The foot is divided into tentacles or arms Most active mollusks Octopi, squids, cuttlefishes, and nautiluses

Activity

Activity round 1 Mollusk Open-circulatory system Cephalopod Closed-circulatory system Gastropod Bivalve Foot Radula Visceral mass Mantle

Activity round 2 Good for slow moving mollusks Food is carried by water and enters through the… Octopi Oxygen and nutrients carried through the body by a… Move with a muscular foot Tiny teeth attached to the… ____ drill through shells of other animals Blood pumped through vessels by a heart ____ scrape algae off rocks Two shells held together by one muscle

Activity round 3 Shell Sea butterflies Soft-bodied mollusks Siphon Most active mollusks Below the mantle Clams Thin layer of tissue Shell-less/single-shelled Not found on slugs

Wrap-Up What is a mollusk? What are the 3 groups? What are the 4 parts in the body plan?