Knowra Mollusc shell Mollusc shell A hard external structure secreted by the mantle of many molluscs, usually made chiefly of calcium carbonate. It protects soft tissues and may grow in layers as the animal grows.
Molluscan mantle : A tissue layer in molluscs that covers internal organs and secretes shell material in shelled species. Mantle cells lay down the organic matrix and minerals that build the shell.
Calcium carbonate : A chemical compound, CaCO₃, occurring in minerals such as calcite and aragonite. It supplies most of the mineral matter in many mollusc shells.
Molluscan shell dating : The use of mollusc shells to estimate the age of archaeological or geological deposits. Shell growth and preserved mineral can provide chronological evidence, subject to contamination and environmental effects.
Nautilus shell : A coiled, chambered external shell used by nautiluses for protection and buoyancy regulation. Its internal chambers make this shell a specialized example of external molluscan armor.
Predator-prey interaction : An ecological interaction in which one organism captures and consumes another. Shells deter predators, while some predators have evolved ways to breach them.
Biomineralization : The process by which living organisms produce minerals that become part of biological structures. Mollusc shells are a prominent example of organism-controlled mineral formation.
Conchiolin : A group of proteins and other organic compounds forming the organic matrix of mollusc shells. This matrix binds mineral crystals and helps shape shell layers.
Stable isotope analysis : The measurement of isotope ratios in materials to infer processes, sources, or past environmental conditions. Isotopes preserved in shell carbonate can record aspects of water temperature and chemistry.
Bivalve shell : A shell composed of two hinged valves, characteristic of clams, mussels, and related molluscs. The paired-valve design contrasts with the single coiled shell common in many gastropods.
Shell-crushing predation : Predation in which an animal breaks a hard shell to reach its soft-bodied prey. This pressure has influenced shell thickness, shape, and defensive features.
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