Seashell Terminology and Study
- Seashells are part of conchology, the study of marine mollusk shells.
- Conchology is the science of studying mollusk shells.
- The study of mollusks, including their shells, is known as malacology.
- Malacologists are people who study mollusks.
- Conchologists and serious collectors are careful not to disturb living populations and habitats.
- Responsible collectors do not often over-collect or disturb ecosystems.
- Many popular books and field guides focus on shell-collecting, particularly marine mollusks.
- Amateurs and professionals contribute to the field of conchology.
- Shell collectors often belong to shell clubs to meet others with similar interests.
- Collecting shells with full data is important for scientific value and potential museum donations.
- Seashells are identified using general or regional shell-collecting field guides.
- Specific scientific books and monographs are used for detailed identification.
- Illustrations and written descriptions are key in identifying shells.
- Constructing functional keys for species-level identification can be challenging.
- Some species cannot be differentiated based on shell characteristics alone.
Occurrence and Impact of Seashells
- Seashells are commonly found in beach drift, deposited by waves and tides.
- Empty seashells are often picked up by beachcombers.
- Commercially sold seashells are usually collected alive and then killed and cleaned.
- Large-scale exploitation of seashells can negatively impact local ecosystems.
- It can also reduce the distribution of rare species.
- Empty molluscan seashells are a sturdy and readily available resource.
- They are often found on beaches, in the intertidal zone, and in the shallow subtidal zone.
- Animals other than humans use seashells for various purposes.
- Hermit crabs use empty seashells for protection.
- Small octopuses use seashells as a form of temporary shelter and protection.
Molluscan Seashells
- Seashells often refer to shells of marine mollusks.
- Marine species of bivalves, gastropods, scaphopods, polyplacophorans, and cephalopods are commonly called seashells.
- Marine gastropods and bivalves are more numerous and often larger than land and freshwater species.
- Tropical and sub-tropical areas have more species of colorful, large, shallow water marine mollusks.
- There are also numerous small species of seashells, known as micromollusks.
- Bivalves are common seashells found on sandy beaches and lagoons.
- There are over 15,000 species of bivalves in marine and freshwater habitats.
- Examples of bivalves include clams, scallops, mussels, and oysters.
- Bivalves have two identical shells held together by a flexible hinge.
- They are mostly filter feeders and are used for food and pearl production.
Cultural Significance of Seashells
- Seashells have been used as currency in various places, including Indian Ocean and Pacific Ocean islands.
- Certain species, such as the money cowry and dentalium tusk shells, have been commonly used as currency.
- Cowry shells were historically used as currency in many African tribes and nations.
- Seashells have been used as tools due to their strength and variety of shapes.
- Native American tribes used shells for wampum belts and hair pipes.
- Seashells have been used as bowls, bathtubs, and baptismal fonts.
- The bailer volute, known as Melo melo, was used by Native Australians to bail out canoes.
- Various species of bivalves have been used as tools, such as scrapers and blades.
- Some marine gastropods have been used for oil lamps, with the shell aperture serving as the oil holder.
- Seashells like oyster shells are used as soil conditioners in horticulture due to their calcium carbonate content.
- The scallop shell is considered a symbol of Saint James the Great in Christianity.
- The left-handed shells of Turbinella pyrum are sacred to the god Vishnu in Hinduism.
- Cowries have been associated with female fertility and used as fertility charms.
- Shells are used for divination in the Santería religion.
- Large sea snail shells, such as the sacred chank (Turbinella pyrum), can be turned into trumpets.
- The Triton shell (Charonia tritonis) is used as a trumpet in Melanesian, Polynesian, Korean, and Japanese cultures.
- The Queen Conch (Lobatus gigas) is used as a trumpet in the Caribbean.
- Children are often told the myth that they can hear the sound of the ocean by holding a seashell to their ear.
- Seashells, particularly cowries, have been used in jewelry and adornment since prehistoric times.
- Shell necklaces have been found in Stone Age graves.
- Seashells have been used in various cultural practices and adornments, such as shell money in certain societies.
- Shell trumpets have been created using seashells.
- Aboriginal communities in Tasmania have historically crafted shell necklaces.
- Seashells have been incorporated into artwork, such as shellwork on the Sydney Harbour Bridge.
Seashells in Construction and Other Uses
- Seashells, specifically from bivalves and gastropods, are primarily composed of calcium carbonate.
- Oyster shells were historically mixed into cement to create shellcrete, which could be used to make bricks, blocks, and platforms.
- The Sabine Pass Lighthouse in Louisiana, near Texas, is a notable example of a structure constructed using shellcrete.
- Shellcrete could also be applied over logs as a building material.
- Seashells have potential as a raw material in the production of lime.
- Some arthropods, such as crabs and horseshoe crabs,
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A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers. The shells are empty because the animal has died and the soft parts have decomposed or been eaten by another animal.
A seashell is usually the exoskeleton of an invertebrate (an animal without a backbone), and is typically composed of calcium carbonate or chitin. Most shells that are found on beaches are the shells of marine mollusks, partly because these shells are usually made of calcium carbonate, and endure better than shells made of chitin.
Apart from mollusk shells, other shells that can be found on beaches are those of barnacles, horseshoe crabs and brachiopods. Marine annelid worms in the family Serpulidae create shells which are tubes made of calcium carbonate cemented onto other surfaces. The shells of sea urchins are called "tests", and the moulted shells of crabs and lobsters are exuviae. While most seashells are external, some cephalopods have internal shells.
Seashells have been used by humans for many different purposes throughout history and prehistory. However, seashells are not the only kind of shells; in various habitats, there are shells from freshwater animals such as freshwater mussels and freshwater snails, and shells of land snails.
