Vertebrates comprise all species of animals within the subphylum Vertebrata. Vertebrates represent the overwhelming majority of the phylum Chordata, with about 69,963 species described. Vertebrates include such groups as the following: jawless fishes jawed vertebrates, which include the cartilaginous fishes tetrapods, which include amphibians, reptiles and mammals bony fishesExtant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, at up to 33 m. Vertebrates make up less than five percent of all described animal species; the vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, the lampreys, do. Hagfish do, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as "Craniata" when discussing morphology. Molecular analysis since 1992 has suggested that hagfish are most related to lampreys, so are vertebrates in a monophyletic sense.
Others consider them a sister group of vertebrates in the common taxon of craniata. The word vertebrate derives from the Latin word vertebratus. Vertebrate is derived from the word vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic chordate body plan: a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it and the gastrointestinal tract below. In all vertebrates, the mouth is found at, or right below, the anterior end of the animal, while the anus opens to the exterior before the end of the body; the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. The defining characteristic of a vertebrate is the vertebral column, in which the notochord found in all chordates has been replaced by a segmented series of stiffer elements separated by mobile joints. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon and coelacanth.
Jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills; the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch; the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their chordate relatives have more than 50 pairs of gills. In amphibians and some primitive bony fishes, the larvae bear external gills, branching off from the gill arches; these are reduced in adulthood, their function taken over by the gills proper in fishes and by lungs in most amphibians. Some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish being irrevocably lost early in the evolution of tetrapods.
While the more derived vertebrates lack gills, the gill arches form during fetal development, form the basis of essential structures such as jaws, the thyroid gland, the larynx, the columella and, in mammals, the malleus and incus. The central nervous system of vertebrates is based on a hollow nerve cord running along the length of the animal. Of particular importance and unique to vertebrates is the presence of neural crest cells; these are progenitors of stem cells, critical to coordinating the functions of cellular components. Neural crest cells migrate through the body from the nerve cord during development, initiate the formation of neural ganglia and structures such as the jaws and skull; the vertebrates are the only chordate group to exhibit cephalisation, the concentration of brain functions in the head. A slight swelling of the anterior end of the nerve cord is found in the lancelet, a chordate, though it lacks the eyes and other complex sense organs comparable to those of vertebrates.
Other chordates do not show any trends towards cephalisation. A peripheral nervous system branches out from the nerve cord to innervate the various systems; the front end of the nerve tube is expanded by a thickening of the walls and expansion of the central canal of spinal cord into three primary brain vesicles: The prosencephalon and rhombencephalon, further differentiated in the various vertebrate groups. Two laterally placed eyes form around outgrowths from the midbrain, except in hagfish, though this may be a secondary loss; the forebrain is well-developed and subdivided in most tetrapods, while the midbrain dominates in many fish and some salamanders. Vesicles of the forebrain are paired, giving rise to hemispheres like the cerebral hemispheres in mammals; the resulting anatomy of the central nervous system, with a single hollow nerve cord topped by a series of vesicles, is unique to vertebrates. All invertebrates with well-developed brains, such as insects and squids, have a ventral rather than dorsal system of ganglions, with a split brain stem running on each side of the mouth or gut.
Sir Henry Peter Rowe, KCB, QC, born Heinz Peter Röhr, was an Austrian-born British lawyer and parliamentary draftsman. Rowe was born Heinz Peter Röhr in Ischl, Austria, on 18 August 1916. In 1935, he enrolled at the University of Vienna, but he arrived at England in 1938 to read law at Gonville and Caius College, Cambridge; as an Austrian, he was interned during the Second World War, but showed signs of academic excellence in the year he had spent at Cambridge, enough that the university awarded him a first-class degree in absentia. In 1941, he was allowed to join the Royal Pioneer Corps in a non-combatant role, was transferred to the 7th Armoured Division where he served as a dispatch rider and was promoted to the rank of Warrant Officer. On demobilisation, Rowe recommenced his interest in law, he was joined the Office of the Parliamentary Counsel soon afterwards. He spent the rest of his career in the office, was responsible for drafting the Licensing Act 1961, the Rent Act 1965, the Scotland Act 1978, the Wales Act 1978 and the Housing Act 1980.
Rowe was promoted to Second Parliamentary Counsel in 1973, First Parliamentary Counsel four years later. He retired in 1981, having been appointed a Knight Commander of the Order of the Bath in 1978, the same year he was made a Queen's Counsel. Rowe died on 13 February 1992, leaving a widow and three children
Moises Denis is an American politician serving as President pro tempore of the Nevada Senate since 2016. A member of the Democratic Party, he has served in the Nevada Senate since 2010, he was a member of the Nevada Assembly from 2004 to 2010. Denis was born in New York City to parents. Denis is Mormon, he served a mission for The Church of Jesus Christ of Latter-day Saints in Uruguay. He studied at Brigham Young University, he has served as a bishop in the LDS Church as well as in other positions. He is a cousin of United States Senator from Florida Marco Rubio. Denis' sister, Micki Denis resides in Kirkland, WA and revealed in a recent interview that she's unable to afford housing and lives out of her car in the parking lot of a local church. Prior to winning election to the Nevada Senate, Denis was a member of the Nevada Assembly, representing Clark County District 28 from 2004 to 2010. In August 2011, majority leader Steven Horsford appointed Denis to lead the caucus election efforts during the 2012 election cycle.
In December 2011, Denis resigned from his job with the Nevada Public Utilities Commission following an alleged conflict between his executive and legislative roles. After the 2012 elections, Denis was chosen by his colleagues to lead the Democratic Caucus as Majority Leader. Nevada Legislator Information Project Vote Smart - Assembly Member Moises'Mo' Denis profile Follow the Money - Mo Denis 2006 2004 campaign contributions Appearances on C-SPAN