Biodiversity- MollusksSarah Whitebloom

Matt JonesEddie Frere

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- MollusksMollusk- 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 typesFoot: 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

CirculationThe oxygen and nutrients are carried through the

mollusk body by a circulatory systemIt is either open or closedOpen circulatory system: blood is pumped through

vessels by a heartOpen circulatory systems work best for slow-moving

mollusks because the demand for oxygen is lowerClosed circulatory system: transport blood through

an animal’s body much more quickly than an open circulatory system; better for faster- moving mollusks

GastropodsShell-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

BivalvesTwo shells that are

held together by one or two powerful muscles

Includes clams, oysters, mussels, and scallops

CephalopodsSoft-bodied mollusks

in which the head is attached to a single foot

The foot is divided into tentacles or arms

Most active mollusksOctopi, squids,

cuttlefishes, and nautiluses

Activity

Activity round 1MolluskCephalopodGastropodBivalveRadula

Open-circulatory system

Closed-circulatory system

FootVisceral massMantle

Activity round 2Good for slow moving

mollusksOctopiMove with a muscular footTiny teeth attached to the…Blood pumped through

vessels by a heart

Food is carried by water and enters through the…

Oxygen and nutrients carried through the body by a…

____ drill through shells of other animals

____ scrape algae off rocksTwo shells held together by

one muscle

Activity round 3ShellSoft-bodied

mollusksMost active

mollusksClamsShell-less/single-

shelled

Sea butterfliesSiphonBelow the mantleThin layer of tissueNot found on slugs

Wrap-Up1. What is a mollusk?2. What are the 3 groups?3. What are the 4 parts in the body plan?