Human lower jaw viewed from the left

The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of most animals.

Arthropods[link]

The mandibles of a Bull ant

In arthropods, the jaws are chitinous and oppose laterally, and may consist of mandibles or chelicerae. These jaws are often composed of numerous mouthparts. Their function is fundamentally for food acquisition, conveyance to the mouth, and/or initial processing (mastication or chewing). Many mouthparts and associate structures (such as pedipalps) are modified legs.

Vertebrates[link]

In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw. The vertebrate jaw is derived from the most anterior two pharyngeal arches supporting the gills, and usually bears numerous teeth.

Jaws of great white shark

The jaw in fish[link]

Moray eels have two sets of jaws: the oral jaws that capture prey and the pharyngeal jaws that advance into the mouth and move prey from the oral jaws to the esophagus for swallowing

The vertebrate jaw probably originally evolved in the Silurian period and appeared in the Placoderm fish which further diversified in the Devonian. The two most anterior pharyngeal arches are thought to have become the jaw itself and the hyoid arch, respectively. The hyoid system suspends the jaw from the braincase of the skull, permitting great mobility of the jaws. While there is no fossil evidence directly to support this theory, it makes sense in light of the numbers of pharyngeal arches that are visible in extant jawed vertebrates (the Gnathostomes), which have seven arches, and primitive jawless vertebrates (the Agnatha), which have nine.

It is thought that the original selective advantage garnered by the jaw was not related to feeding, but to increased respiration efficiency. The jaws were used in the buccal pump (observable in modern fish and amphibians) that pumps water across the gills of fish or air into the lungs in the case of amphibians. Over evolutionary time the more familiar use of jaws (to humans), in feeding, was selected for and became a very important function in vertebrates. Many teleost fish have substantially modified their jaws for suction feeding and jaw protrusion, resulting in highly complex jaws with dozens of bones involved.

The jaw in amphibians, reptiles, and birds[link]

The jaw in tetrapods is substantially simplified compared to fish. Most of the upper jaw bones (premaxilla, maxilla, jugal, quadratojugal, and quadrate) have been fused to the braincase, while the lower jaw bones (dentary, splenial, angular, surangular, and articular) have been fused together into a unit called the mandible. The jaw articulates via a hinge joint between the quadrate and articular. The jaws of tetrapods exhibit varying degrees of mobility between jaw bones. Some species have jaw bones completely fused, while others may have joints allowing for mobility of the dentary, quadrate, or maxilla. The snake skull shows the greatest degree of cranial kinesis, in order to allow the snake to swallow large prey items.

The jaw in mammals[link]

In the evolution of the mammalian jaw, two of the bones of the jaw structure (the articular bone of the lower jaw, and quadrate) were reduced in size and incorporated into the ear, while many others have been fused together.^[1] As a result, mammals show little or no cranial kinesis, and the mandible is attached to the temporal bone by the temporomandibular joint. Temporomandibular joint disorder is a common disorder of this joint^{[citation needed]}, and can cause pain and loss of joint mobility.

Sea urchin jaws[link]

Sea urchins possess unique jaws which display 5-part symmetry, termed the "Aristotle's lantern". Each unit of the jaw holds a single, perpetually-growing tooth composed of crystalline calcium carbonate.

See also[link]

• Tooth
• Gnathostomata - jawed vertebrates
• Muscles of mastication
• Otofacial syndrome
• Predentary
• Premaxilla
• Prognathism
• Rostral bone

References[link]

External links[link]

Look up jaw in Wiktionary, the free dictionary.

• Prehistoric Fish Had Most Powerful Jaws
• Jaw at the US National Library of Medicine Medical Subject Headings (MeSH)

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (June 2010)

Jean-Baptiste de Laubier, also known by his artist name Para One, is a French electronic music producer and film director.

Music career[link]

Laubier first came to prominence as one of the main producers of French rap group TTC, and was responsible for producing their 2004 signature tune Dans Le Club. With fellow TTC producer Tacteel he made up the now defunct live/improvised electro outfit Fuck-A-Loop (whose only recorded material prior to 2007's nine hour digital album The Early Aughties was a 2006 remix of Ellen Allien's Down). In 2007, he remixed The Prime Time of Your Life by French house duo Daft Punk. In 2008, Para One got his biggest commercial hit by remixing #1-hit song Greatful Days by Japanese popstar Ayumi Hamasaki. This song was released on the album Ayu-mi-x 6: Gold.

He also produced the soundtrack of the film Water Lilies directed by Céline Sciamma in 2007. In 2011, the song "Always" from his and Tacteel's Fair Enough EP was featured in the same director's film Tomboy.

Film career[link]

Apart from his musical career, Jean-Baptiste de Laubier also works as a film director. In 2009, he directed the short movie It Was On Earth That I Knew Joy for French brand Sixpack France. The movie was presented on February 20, 2010 at SCION Installation, Los Angeles.^[1]

Discography[link]

• Para One – Beat Down EP (2003)
• Para One – Clubhoppn EP (2005)
• Para One – Dundun-Dun Single (2006)
• Para One – Dundun-Dun - Remixes (2006)
• Para One – Epiphanie (2006)
• Para One – Midnight Swim (2007)
• Para One – Naissance des pieuvres OST (2007)
• Para One – Kiwi / Toadstool (2010)
• Para One – Animal Style / Nevrosis (2010)
• Das Glow & Para One – Pulsar / Freeze (2011)
• Para One & Tacteel – Fair Enough EP (2011)
• Para One & San Serac pres. Slice & Soda – Year of the Dragon (2011)
• Para One & Teki Latex – 5th Dimension (2011)

Filmography[link]

• Les Premières Communions (2004), short movie
• Cache Ta Joie (2005), short movie
• It Was On Earth That I Knew Joy (2009), short movie

Sources[link]

External links[link]

• Live at CTM.07 festival in Berlin
• "It Was On Earth That I Knew Joy" Official trailer

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