How are seashells made?
Beautifully patterned colors and intricate architecture can make a seashell look like a work of art, but the value of the shell to its maker is the protection it gives against predators, the drying sun, or wave damage. Seashells are made by mollusks, but not all mollusks make shells. Squids, slugs and many other mollusks gained greater freedom of movement by giving up the shell-making ability of their ancestors. Our mineral structures, bone and teeth, form internally. How does a mollusk produce a shell outside its body? The secret is a structure called the mantle. The surface cells of this flap of tissue produce a protein and carbohydrate coating in which dissolved minerals are concentrated and crystallized. The mineral part of seashells is calcium carbonate, and the chemicals needed to make it are abundant, in dissolved form, in seawater. Bivalve mollusks, such as clams, have two shells attached by a hinge. The youngest part of the shell is the edge. As the animal grows, a shallow fol
Most seashells belong to creatures called mollusks. Snails, oysters and clams are mollusks. Mollusks have soft bodies and no bones. They need shells for protection, says 3-2-1 Contact magazine. A mollusk starts to grow a shell when it is very tiny. The shell starts out as bits of calcuim (four bones are made of the same stuff). The shell keeps growing along with the mollusk. Snails, whelks and many mollusks grow shells in a spiral shape. Their body organs are arranged inside the shell. Bivalves, such as clams and oysters, are mollusks with two shells that open and close like a book. Seashells come in all shapes and sizes. The biggest is the giant clam: its 4-foot-long shell can weigh up to 500 pounds. Some people have used these shells as bathtubs!
Where do seashells come from? Seashells are the external skeletons of a class of marine animals called Mollusks. Where people have our skeletons on the inside of our bodies, mollusks have their skeletons on the outside of theirs. This way they help protect the creatures from predators, strong currents and storms, help camouflage the animal, and do many other things. Seashells are primarily made of calcium, a hard mineral, just as our own bones are. http://www.seashellsandsuch.
