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Have you ever been come the ocean or eaten seafood? If you have, climate you probably have actually encountered members the the phylum Mollusca. Mollusks encompass snails, scallops, and also squids, as presented in Figure below. There are an ext than 100,000 known varieties of mollusks. Around 80 percent the mollusk species are gastropods.

api/deki/files/10741/f-d_131a73ce7e3711361df2c05803561d0adf9da9327b2197512b534a09%252BIMAGE_THUMB_POSTCARD_TINY%252BIMAGE_THUMB_POSTCARD_TINY.png?revision=1" />Basic Mollusk human body Plan. The simple body plan shown below varies amongst mollusk classes. Because that example, numerous mollusk varieties no longer have actually shells. Do you know which ones?

Two distinct features of mollusks space the mantle and radula (see Figure above). The mantle is a great of organization that lies in between the shell and the body. It secretes calcium lead carbonate to form the shell. It creates a cavity, called the mantle cavity, in between the mantle and also the body. The mantle cavity pumps water for filter feeding. The radula is a feeding body organ with this made of chitin. It is located in front of the mouth in the head region. Herbivorous mollusks use the radula come scrape food such as birds off rocks. Predatory mollusks usage the radula come drill holes in the shells of your prey.

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Mollusks have actually a coelom and a finish digestive system. Their excretory system is composed of tube-shaped organs called nephridia (see Figure above). The guts filter rubbish from human body fluids and also release the waste right into the coelom. Terrestrial mollusks exchange gases through the bordering air. This occurs across the lining the the mantle cavity. Aquatic mollusks “breathe” under water with gills. Gills are thin filaments that absorb gases and exchange them in between the blood and also surrounding water.

Mollusks have a circulatory device with one or 2 hearts that pump blood. The heart is a muscular organ that pumps blood v the circulatory system when its muscle contract. The circulatory system may be open or closed, relying on the species.

The major classes the mollusks vary in structure and function. You deserve to read about some the their distinctions in Figure below.

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Use this figure to compare and contrast gastropods, bivalves, and cephalopods

Mollusk Reproduction

Mollusks reproduce sexually. Most types have different male and also female sexes. Gametes space released into the mantle cavity. Fertilization might be inner or external, depending upon the species. Fertilized eggs construct into larvae. There might be one or more larval stages. Each one is various from the adult stage. Mollusks have actually a distinctive larval kind called a trochophore. The is a tiny organism with cilia because that swimming.