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What Is Inside a Seashell?

Sea shells are the skeletal remains of marine animals called mollusks. Made up of calcium, as human bones are, the shells provide protection from currents, predators and also provide camouflage. They are often found on beaches, with the animal that inhabited the shell long deceased. Remains of the animal inside have either rotted away or been eaten by other creatures, leaving behind the popular collectors item.

Species
- There are over 85,000 species of mollusks, varying dramatically throughout the worlds oceans due to local climatic conditions. The most common species are Gastropoda, more commonly known as slugs or snails. Other species include Aplacophora, Bivalvia, Cephalopoda, Polyplacophora, Helcionelloida, Monoplacophora, Rostroconca and Scaphopoda.
Organs
- Within the external skeleton, a mollusk has many of the same organs as a human being, including a heart, kidneys, stomach, intestines and reproductive organs. Oral blades enable the creature to sift through food particles on rock faces or surrounding water. Mollusks also have arms which enable it to move over surfaces and specially adapted Byssus threads, which enables it to cling to surfaces.
Pearls
- Pearls are naturally produced within mollusks due to the build up of calcium carbonate in minute crystalline form. Any mollusk can produce pearls, however, they require the right set of conditions to from properly. They are an extremely valuable commodity, however, and are also incredibly rare.
Conchology
- Both the research and study of mollusks and the hobby of collecting mollusks is known as conchology. Shell collecting is a common practice all over the globe, with many organizations and societies enabling collectors to meet and compare collections. It is a popular hobby due to the beauty and intrigue the shells provide.

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