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The Phylum Molluska. By: Zach Lashbrook & Sarah Briggs. Different Types of Mollusks. Cephalopods Gastropoda Bivalvia Polyplacophora. Cephalopoda. Squid. Octopus. Cuttlefish. Octopuses & Squids. Gastropoda. gastro means stomach or belly pod means foot.
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The Phylum Molluska By: Zach Lashbrook & Sarah Briggs
Different Types of Mollusks • Cephalopods • Gastropoda • Bivalvia • Polyplacophora
Cephalopoda • Squid • Octopus • Cuttlefish Octopuses & Squids
Gastropoda gastro means stomach or bellypod means foot • Snails • Whelks • Periwinkles • Abalone • Slugs
Bivalvia • Scallops • Clams • Oysters • Mussels
The Habitat • They are marine animals • Some found in coastal areas and others in the deepest parts of the ocean • Most live in the bottom sediments
The Habitat • Cephalopods 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 source • They eat most anything • Different Mollusks eat different things • Snails eat leaves • Some carnivores and eat other mollusks and worms • Squid 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 predators • Sea slugs avoid predation by leaving a bad taste in predators mouth • The mollusks in the class bivalvia have two shells connected by a flexible hinge that clamp close • Octopuses and squids emit clouds of dark colored ink to get away from predators
Describe the mollusks body plan • All mollusks have a similar body plan • Usually include: • Foot • Gut • Mantle • Shell
The Foot • Soft • Muscular • Structure that usually contains the mouth
The Gut • The gut is the mollusks digestive tract • Digests its food • By the stomach
The Mantle • Layer of tissue that surrounds its body • Thin • Delicate
The Shell • Formed by glands in the mantle • Protect the mollusk • Not all mollusks have one • Some are outside some are internal
The Radula • A 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 Body • The 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.
Reproduction • Some swarm together to breed, some seek partners, and few fertilize themselves • Some 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 System • Blood doesn’t circulate entirely within vessels • Collected from gills • Pumped through the heart • Released directly into spaces in the tissues • Returns to gills
Closed Circulatory System • Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness • In 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 nephridia • Nephridia 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 system • Mouth • Anus • Complex 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
Works Cited • Brusca, Richard C; and Gary J. Brusca. “Phylum Mollusea.” Invertebrates. 2nd ed. 2003 • Gilpin, 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.<http://student.britannica.com/comptons/article 204814/mollusk>
Works Cited • Phylum Mollusca: Mollusks. Helena Curtis and N. Sue Barnes. WORTH PUBLISHERS, INC. 1 April 2009. http://www.infusion.allconet.org/webquest/invertebrates.h tml • "How Smart Is the Octopus? Bright Enough to Do the Moving Rock-Trick." Kitty Mowmow's Animal Expo. 9 Apr. 2009 <http://www.kittymowmow.com/2008/06/27/how-smart-is- the- octopus-bright-enough-to-do-the-moving-rock- trick/>. • "Palau 2004: My Photo Gallery." Palau 2004. 10 Apr. 2009 <http://www.seerious.com/Palau2004.htm>. “Mollusks and • Echinoderms.” 2009. 8 April 2009. <http://74.125.95.132/search?q=cache:TZ4VBK217egJ:fair mont.k1>