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By Eric McClung

& Mitchell Christopher PLAY INTRO SOUND PLAY BACKGROUND SOUND

Habitat

Food

Importance to Humans

Classes

Reproductive system

Credits

Nervous System

Unique Characteristics

Respiratory System

Circulatory system

Excretory System

Digestive system

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• Most anywhere on earth

• ¾ of the planets surface

• Can live in fresh and salt water as well as on land

• Must be a damp environment

• If the plants are scarce so are mollusks

• Can be found in ponds lakes and rivers

Squid video

• Some live on sediment bottom, or cling to rocks

• Some will glide over reefs

• Other types live in the deep dark part of the sea like the squid

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• They feed on most anything • Gastropods are usually vegetarians• Slugs and Snails eat plants• Limpets and Winkles eat algae• Many mollusks have a radula • The Radula is used to rasp away at

food• It is covered with tiny little “teeth”

Definitions: limpets, Winkles

• Gastropods, like whelk usually eat dead animals and few species hunt

• Marine Carnivores, cephalopods, are an extremely formidable predator

• The squid and cuttlefish have two extra long tentacles that capture their prey

• The squid has very good eye sight that also helps them judge distance

Return to menuDefinitions: whelk

• 30,000 tons of squid are caught off the coast of Argentina alone

• Roman is the most popular type of snail that is eaten in France, there it is called escargots

• Some mollusks are used for buttons and calcium pills

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Gastropods = snails slugs etc.

• Most live in the ocean

• Five of the seven that live in the ocean are: Chiton, tusk shells, cephalopods, monolacophs, and aplacophs

• Cephalopoda-(web definition)

• Bivalvia-(web definition)

• Gastropoda- (web definition)

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• Some mollusks fertilize themselves • Others will swarm and breed• Some will only use a single partner• Mollusks also produce large amounts

of eggs• Many are eaten before they hatch• When a mollusks reproduces sexually

it reproduces with a large organ called a gonad

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A diagram of the inside of a squid

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• The nervous system is quite unique it includes a ring of a nervous tissue that is around the esophagus that is then connected with two pairs of vertical nerve cords that got to the muscles of the foot and mantle

• No formal nervous system but it has a series of ganglia that conduct impulses

• Some mollusks have simple nervous systems like clams, but others have more complex nervous system like octopuses

Return to menuDefinitions: ganglia, esophagus

• There are ten thousand species of mollusks

• Most mollusks have a soft body with a hard shell (ex. Snails)

• Some squids have nerve cells about 100 times bigger than human nerve cells.

Rare Squid sighting in natural habitat video Return to menu

• Numerous mollusks have gills to absorb water into the mantle cavity, once in the cavity the oxygen will be siphoned

• After the oxygen has been removed it will enter the blood stream, while simultaneously removing carbon dioxide

• Land dwellers will have lungs which are always moist, also the opening or mouth is usually found behind the head

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• Mollusks have a heart with extensive branched and blood vessels that carry blood from the heart to all other parts of the body

• There hearts are pericardial cavities, which is a part of the body cavity or coelom

• Contains a simple heart

• In a slow moving Mollusks, blood is pumped from the heart through open spaces called sinuses

• Blood then travels into vessels that move through gills and then returns to the heart

• Referred to as an “open” circulatory system

Return to menuDefinitions: , sinuses, open circulatory system, coelom

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• A mollusks’ excretory system has an anus it also has an organ called a nephridium that get rid of the wastes

• Made up of glandular epithelium which takes nitrogenous wastes from blood passing though them

• The waste material is then discharged to the outside by pores near the anus

Definitions: nephridium

• A mollusks must capture its food through a siphon system that travels to a digestive gland and into its intestine, then the waste is removed by anus

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