The Phylum MolluskaBy: Zach Lashbrook & Sarah Briggs

Different Types of MollusksCephalopods

Gastropoda

Bivalvia

Polyplacophora

CephalopodaOctopus

CuttlefishSquid

Octopuses & Squids

GastropodaSnailsWhelksPeriwinklesAbaloneSlugs gastro means stomach or belly pod means foot

BivalviaClamsMussels OystersScallops

Polyplacophora

The HabitatThey are marine animals

Some found in coastal areas and others in the deepest parts of the ocean

Most live in the bottom sediments

The HabitatCephalopods they are primarily free-swimming species

A lot mollusks inhabit rocky seashore environments where their low dome-shaped shells are well suited.

Some have been found at depths of 2,200 feet or more

Examples of their food sourceThey eat most anythingDifferent Mollusks eat different thingsSnails eat leavesSome carnivores and eat other mollusks and wormsSquid are predators

How are they important to humans?And a lot of mollusks such as squids, snails, octopuses, and clams provide us with food

Their pearls can be used for jewelry

Their shells can be used for tools, decorations, containers, musical devices, etc.

How are they important to the environment?They are a major part of the food chain

They are both predators and prey

Some are decomposers and help with the environment

How are they unique?Mollusks bodies are all very soft but have many ways of protecting themselves from predatorsSea slugs avoid predation by leaving a bad taste in predators mouthThe mollusks in the class bivalvia have two shells connected by a flexible hinge that clamp closeOctopuses and squids emit clouds of dark colored ink to get away from predators

Describe the mollusks body planAll mollusks have a similar body plan Usually include:FootGutMantleShell

The FootSoft

Muscular

Structure that usually contains the mouth

The GutThe gut is the mollusks digestive tract

Digests its food

By the stomach

The MantleLayer of tissue that surrounds its body

Thin

Delicate

The ShellFormed by glands in the mantle

Protect the mollusk

Not all mollusks have one

Some are outside some are internal

The RadulaA feeding structure

Found in the mollusks mouth mouth

Uses the radula to scrape off bits of plant or animal matter that the animal uses for food.

The Mollusks BodyThe mollusks body is really soft and a lot do not have a skeleton

Some have a shell on the outside for support and protection

Mollusks such as the Squid have an internal shell throughout their body

How do they get oxygen?Octopus and squid breath through their gills

Snails mantle cavity has a hole under the shell that sucks in oxygen

How do they get rid of Carbon Dioxide?The breathing chamber in the mollusk is lined with blood vessels. Blood in the vessels can get rid of carbon dioxide and pick up oxygen. The heart pumps the blood to every cell in the body. The cells take oxygen from the blood and give up the waste gas carbon dioxide.

ReproductionSome swarm together to breed, some seek partners, and few fertilize themselvesSome are immobile such as oysters and mussels can produce both female and male sex cells in different periods of its life. They will shed their sex cells and the tides will take them to where the sperm meets the egg and fertilizes it.

What is their nervous system like?They have a relatively complex nervous system

Varies with the species

Octopuses are thought to be among most intelligent of all invertebrates

Do they have a specific sensory structures?Sensory organs are contained in the head

Some have very advanced sensory structures

Which mollusks have advanced sensory organs?Clams have poorly developed sensory structures

Octopus have advanced sensory structures

How does having advanced sensory organs benefit them? If these animals have more advanced sensory organs then they can find their prey and scope them out easier. Also, if they are the prey, then they could smell or see predators coming and escape from them.

Open Circulatory SystemBlood doesnt circulate entirely within vesselsCollected from gillsPumped through the heartReleased directly into spaces in the tissuesReturns to gills

Closed Circulatory SystemClosed circulatory systems have the blood closed at all times within vessels of different size and wall thicknessIn this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities

What type of circulatory system do they have?Most have an open circulatory system

The Cephalopods are the group that have a closed circulatory system

What is their excretory system like?The excretory functions are carried out by a pair of nephridiaNephridia are tubular structures that collects fluids from the coelom and exchange salts and other substances with body tissues as the fluid passes along the tubules for excretion

The nephridia empty into the mantle cavity

How do they digest their food?They have a complete and ciliated digestive systemMouthAnusComplex stomach (varies with diet)Food taken up by cells lining the digestive glands arising from the stomach, then to the blood

How do they digest their food?Undigested materials are compressed and packaged

Discharged through the anus into mantle cavity

Carried away by currents in water

Squids and Giant Squids

Sea Slugs

Clams

Oysters

Mussels

Scallops

Octopus

Snails

Works CitedBrusca, Richard C; and Gary J. Brusca. Phylum Mollusea. Invertebrates. 2nd ed. 2003Gilpin, Daniel. Mollusks. Animal Kingdom Classification; Snails, Shellfish, and Other Mollusks. 2006.Miller, Kenneth R., and Joseph Levin. Animals: Invertebrates. Biology The Living Science. 1998"Mollusk." Student's Encyclopedia. 2009. Britannica Student Encyclopedia. 7 April 2009.

Works CitedPhylum Mollusca: Mollusks. Helena Curtis and N. Sue Barnes. WORTH PUBLISHERS, INC. 1 April 2009. http://www.infusion.allconet.org/webquest/invertebrates.html "How Smart Is the Octopus? Bright Enough to Do the Moving Rock-Trick." Kitty Mowmow's Animal Expo. 9 Apr. 2009 . "Palau 2004: My Photo Gallery." Palau 2004. 10 Apr. 2009 . Mollusks and Echinoderms. 2009. 8 April 2009.