Phylum Mollusca Gastropods Bivalves Cephalopods Body plan includes

Phylum: Mollusca Gastropods, Bivalves & Cephalopods

Body plan includes 5 main parts

n Mollusks have a free swimming larval stage called a trochophore

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https: //www. youtube. com/watch? v=z. IEGQo 80 WTU 3 main groups of Mollusks n n n 1. Gastropods – shell-less or single shelled mollusks that move by using a muscular foot. Means “stomach footed” Most numerous group of mollusks ~ 75, 000 Gastropods are the only group to invasde land – snails! Ex. Sea hares – can squirt ink at predators Nudibranches – sea slugs, have chemicals in their bodies that taste bad. Can recycle nematocysts from cnidarians they https: //www. youtube. com/watch? v=_Ad. UJVUXhyg

n n 2. Bivalves – two shells held together by two powerful muscles called abductor muscles. Ex. Clams, oysters, mussels and scallops. Scallops can flap their shells to move when threatened. Filter water over gills use mucus and cilia on gills to trap food particles.

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NAUTILUS https: //www. youtube. com/watch? v=HIRCI 0 G 19 Uw n This animal can be found in the tropical waters of Indian and Pacific oceans, near the coast of Fiji, Japan, Australia, New Caledonia…Nautilus prefers life near the coral reefs, on a depth between 900 and 2000 feet. Major factor that affects survival of nautilus in the wild is overfishing. People collect nautiluses because of their beautiful shells that are sold as ornament. Nautilus is not listed as endangered species due to lack of data (number of remaining animals in the wild is unknown).

n n Males are more numerous in the nature (75% of males vs. 25% of females). Scientists are not sure why this happens. Nautiluses are living fossils. They are living on the planet 500 million years without any changes in their appearance. Nautiluses inhabited the Earth 265 million years before dinosaurs appeared. Nautilus has a long lifespan. It can survive more than 15 years in the wild. Nautilus has 90 long tentacles, located outside the shell. Tentacles are covered with ridges and grooves which facilitate manipulation of prey.