Mollusc shell in the context of Nacreous

A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material.

Though some beaches form on inland freshwater locations such as lakes and rivers, most beaches are in coastal areas where wave or current action deposits and reworks sediments. Erosion and changing of beach geologies happens through natural processes, like wave action and extreme weather events. Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for the beach. However, these natural forces have become more extreme due to climate change, permanently altering beaches at very rapid rates. Some estimates describe as much as 50 percent of the earth's sandy beaches disappearing by 2100 due to climate-change driven sea level rise.

In genetics, the phenotype (from Ancient Greek φαίνω (phaínō) 'to appear, show' and τύπος (túpos) 'mark, type') is the set of observable characteristics or traits of an organism. The term covers all traits of an organism other than its genome, however transitory: the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties whether reversible or irreversible, and all its behavior, from a peacock's display to the phone number you half remember. An organism's phenotype results from two basic factors: the expression of an organism's unique profile of genes (its genotype) and the influence of environmental factors experienced by that same organism which influence the variable expression of said genes, and thereby shape the resulting profile of defining traits. Since the developmental process is a complex interplay of gene-environment, gene-gene interactions, there is a high degree of phenotypic variation in a given population that extends beyond mere genotypic variation.

A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and again in his 1982 book The Extended Phenotype suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams as "extended phenotypes".

Paleoclimatology (British spelling, palaeoclimatology) is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate.

Paleoclimatology uses a variety of proxy methods from Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils. Combined with techniques to date the proxies, the paleoclimate records are used to determine the past states of Earth's atmosphere.

An exoskeleton (from Ancient Greek έξω (éxō) 'outer' and σκελετός (skeletós) 'skeleton') is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. that of a human) which is enclosed underneath other soft tissues. Some large, hard and non-flexible protective exoskeletons are known as shell or armour.

Examples of exoskeletons in animals include the cuticle skeletons shared by arthropods (insects, chelicerates, myriapods and crustaceans) and tardigrades, as well as the skeletal cups formed by hardened secretion of stony corals, the test/tunic of sea squirts and sea urchins, and the prominent mollusc shell shared by snails, clams, tusk shells, chitons and nautilus. Some vertebrate animals, such as the turtle, have both an endoskeleton and a protective exoskeleton.

A midden is an old dump for domestic waste. It may consist of animal bones, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and ecofacts associated with past human occupation.

These features provide a useful resource for archaeologists who wish to study the diets and habits of past societies. Middens with damp, anaerobic conditions can even preserve organic remains in deposits as the debris of daily life are tossed on the pile. Each individual toss will contribute a different mix of materials depending upon the activity associated with that particular toss. During the course of deposition, sedimentary material is deposited as well. Different mechanisms, from wind and water to animal digs, create a matrix which can also be analysed to provide seasonal and climatic information. In some middens individual dumps of material can be discerned and analysed.

Cuttlefish, or cuttles, are marine molluscs of the family Sepiidae. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control of buoyancy.

Cuttlefish have large, W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 to 25 cm (6 to 10 in), with the largest species, the giant cuttlefish (Sepia apama), reaching 50 cm (20 in) in mantle length and over 10.5 kg (23 lb) in mass.

The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug).

Some snails also possess an operculum that seals the opening of the shell, known as the aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group.

Nacre (/ˈneɪkər/ NAY-kər, also /ˈnækrə/ NAK-rə), also known as mother-of-pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent.

Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as flame structure as is found in conch pearls.

An endoskeleton (from Ancient Greek ἔνδον (éndon), meaning "inside", and σκελετός (skeletós), meaning "skeleton") is a structural frame (skeleton) — usually composed of mineralized tissue — on the inside of an animal, overlaid by soft tissues. Endoskeletons serve as structural support against gravity and mechanical loads, and provide anchoring attachment sites for skeletal muscles to transmit force and allow movements and locomotion.

Vertebrates and the closely related cephalochordates are the predominant animal clade with endoskeletons (made of mostly bone and sometimes cartilage, as well as notochordal glycoprotein and collagen fibers), although invertebrates such as sponges also have evolved a form of "rebar" endoskeletons made of diffuse meshworks of calcite/silica structural elements called spicules, and echinoderms have a dermal calcite endoskeleton known as ossicles. Some coleoid cephalopods (squids and cuttlefish) have an internalized vestigial aragonite/calcite-chitin shell known as gladius or cuttlebone, which can serve as muscle attachments but the main function is often to maintain buoyancy rather than to give structural support, and their body shape is largely maintained by hydroskeleton.

The Diaguita people are a group of South American Indigenous people native to the Chilean Norte Chico and the Argentine Northwest. Western or Chilean Diaguitas lived mainly in the Transverse Valleys that incise semi-arid mountains. Eastern or Argentine Diaguitas lived in the provinces of La Rioja and Catamarca and part of the provinces of Salta, San Juan and Tucumán. The term Diaguita was first applied to peoples and archaeological cultures by Ricardo E. Latcham in the early 20th century.

Ancient Diaguitas were not a unified people; the language or dialects used by them seems to have varied from valley to valley and they were politically fragmented into several chiefdoms. Coastal and inland Chilean Diaguitas traded, as evidenced by the archaeological findings of mollusc shells in the upper courses of Andean valleys.

The mantle (also known by the Latin word pallium meaning mantle, robe or cloak, adjective pallial) is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.

In many species of molluscs the epidermis of the mantle secretes calcium carbonate and conchiolin, and creates a shell. In sea slugs there is a progressive loss of the shell and the mantle becomes the dorsal surface of the animal.