Marine Sciences 2nd semester 1st quarter Phylum Mollusca

Vocabulary Acid (acidic) Hydrologic cycle Veliger Base (basic Hypersaline Nephridia Brackish Ion Cerata Buffer PH Siphon Condense Thermocline Chromatophores Crystallization Water vapor Sepia Desalination Mantle Colemates Distillation Foot Protostomes Evaporate Radula POLYPLACOPHORES Filtration Trochophore

Phylum Mollusca Molluscas Marine, some freshwater and/or terrestrial http://content.answcdn.com/main/content/img/McGrawHill/Encyclopedia/images/CE431300FG0010.gif Phylum Mollusca Molluscas Marine, some freshwater and/or terrestrial Coelomates – body cavity fully lined with mesoderm Protostomes – first embryonic opening  mouth The Mollusks range from squid and octopuses Snails , sea slugs (snails without shells) , oysters, clams and Conches

Who is in Phylum Mollusca All Mollusca have Ventral, muscular foot Radula Mantle (secretes shell, when present)

The Mantle Is a muscular bag that surrounds the gills and most organs It’s used to circulate the water through the the organism. Some use it for feeding some use it for propulsion Secrets the calcium carbonate shell

Muscular Foot It’s located beneath the head Slugs and snails use foot to crawl In other mollusk for example like squids the foot becomes the tentacles Geoduck

Radula Think of it as tongue bearing rough scraping teeth. Different types of mollusk have different types of radula In cone snails the radula takes the form of a harpoon with barb and venom that paralyzes. http://video.nationalgeographic.com/video/weirdest-cone-snail

The Six Classes of Mollusks Class Gastropoda Class Cephalopoda Class Polyplacophora Class Bivalvia Class Monoplacophores Class Scaphopods

Monoplacophores and Polyplacophores Also emerging at the same time as gastropods, these shells all live on seabeds and only reach about an inch in total length. POLYPLACOPHORES Emerging 500 million years ago, polyplacophores (aka chitons) live a few inches below the water's surface on reefs. Their shells consist of eight tiny plates layered as shingles with pores

SCAPHOPODS these shells washed up on beaches around the world. They are small, curved, white tubes formed for specialization purposes. There maximum length is five inches and they tend to be white in color

GASTROPODA These shells emerged 600 million years ago. No other class has as many species (more than 50,000) or are as widely collected Marine, freshwater and terrestrial herbivores Shell is coiled (if present) Body symmetry is distorted by torsion Many have single organs gills and nephridia (simple kidneys) Ex. Snails

Gastropods that lack shell Subclass Opisthobranchia Slugs, sea slugs, and nudibranchs Some have spines with toxins Some feed on cnidarians and have the ability to eat the nematocysts without firing or digesting them. Nematocysts are incorporated into cerata on the nudibranch’s back Cerata are unique organs that look like soft tufts and serve both as gills and defensive weapons armed with stolen nematocysts

Class Bivalvia Mollusks that have two hinged shells Marine and freshwater sessile filter feeders Lack a head like other mollusks Mantle acts like pump water into the organism for oxygen Commercial pearl fisherman Ex. Clams, mussels, oysters and scallops

Bivalves are important Why are bivalves important Provide habitat , shelter Ecosystem engineer, and a foundation specie Are a food source for various organism Help in filtration of the water Shoreline protection Important commercial specie

Filter Feeders

CEPHALOPODS Emerging about 525 million years ago, these shells are the most evolved of all six classes and the mollusks are carnivorous. Their shells appear as an "outer hull", but are more commonly internal. There are about 600 of these living species today and, including the giant squid, they may reach lengths of 65 feet

CEPHALOPODS Marine; active predators Possess tentacles for prey capture Have little or no shell Foot became arms Specialized foot known as siphon - which enables them to move Chromatophores – pigment sacs in their skin cells that allow them to change color Sapia black ink sac Have eyes and nervous system Ex. Octopi, squid, cuttlefish & nautili

INK

Shape shifter

Dissection Tools

Oyster Anatomy

Good Oyster Vs. Bad Oyster

Oyster Life cycle Veliger – planktonic larval stage of mollusks Trochophore –Initial larval stage of mollusks

Dissection

Oyster Lab Make sure you clean up after the lab if not you will have negative points deducted from you Rinse all the tools off then place them in tray Place waste in the designated container Turn in Lab before you leave Remember Lab is worth as much a test grade so take it serious