Transcript Slide 1
START PRESENTATION By Eric McClung & Mitchell Christopher PLAY INTRO SOUND PLAY BACKGROUND SOUND PLAY BACKGROUND SOUND Habitat Digestive system Food Nervous System Reproductive system Unique Characteristics Importance to Humans Respiratory System Classes Circulatory system Credits Excretory System • 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 Return to menu • • • • • • 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 Definitions: whelk Return to menu • 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 Gastropods = snails slugs etc. Return to menu • 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) Return to menu • • • • 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 Return to menu Return to menu A diagram of the inside of a squid • 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 Definitions: ganglia, esophagus Return to menu • 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 Return to menu • 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 Definitions: , sinuses, open circulatory system, coelom Return to menu Definitions: nephridium • 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 Return to menu • 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 Return to menu START PRESENTATION