Deuterostomes constitute a superphylum of animals. It is a sister clade of Protostomia. Deuterostomia is a subtaxon of the Bilateria branch of the subkingdom Eumetazoa, within Animalia, are distinguished from protostomes by their deuterostomic embryonic development. Deuterostomes are known as enterocoelomates because their coelom develops through enterocoely. There are three major clades of deuterostomes: Chordata Echinodermata Hemichordata Previously, Deuterostomia included the phyla Brachiopoda, Bryozoa and Phoronida based on embryological characteristics. However, Superphylum Deuterostomia was redefined in 1995 based on DNA molecular sequence analyses when the lophophorates were removed from it and combined with other protostome animals to form superphylum Lophotrochozoa; the phylum Chaetognatha may belong here, but molecular studies have placed them in the protostomes more often. Extinct deuterostome groups may include the phylum Vetulicolia. Echinodermata and Hemichordata form the clade Ambulacraria.
In both deuterostomes and protostomes, a zygote first develops into a hollow ball of cells, called a blastula. In deuterostomes, the early divisions occur perpendicular to the polar axis; this is called radial cleavage, occurs in certain protostomes, such as the lophophorates. Most deuterostomes display indeterminate cleavage, in which the developmental fate of the cells in the developing embryo are not determined by the identity of the parent cell. Thus, if the first four cells are separated, each cell is capable of forming a complete small larva. In deuterostomes the mesoderm forms as evaginations of the developed gut that pinch off, forming the coelom; this is called enterocoely. Another feature present in both the Hemichordata and Chordata is pharyngotremy. A hollow nerve cord is found in all chordates, including tunicates; some hemichordates have a tubular nerve cord. In the early embryonic stage, it looks like the hollow nerve cord of chordates; because of the modified nervous system of echinoderms, it is not possible to discern much about their ancestors in this matter, but based on different facts it is quite possible that all the present deuterostomes evolved from a common ancestor that had pharyngeal gill slits, a hollow nerve cord and longitudinal muscles and a segmented body.
It could have resembled the small group of Cambrian urochordate deuterostomes named Vetulicolia. The defining characteristic of the deuterostome is the fact that the blastopore becomes the anus, whereas in protostomes the blastopore becomes the mouth; the deuterostome mouth develops at the opposite end of the embryo from the blastopore and a digestive tract develops in the middle, connecting the two. In many animals these early development stages evolved in ways that no longer reflect these original patterns. For instance, humans have formed a gut tube at the time of formation of the mouth and anus; the mouth forms first, during the fourth week of development, the anus forms four weeks temporarily forming a cloaca. The majority of animals more complex than jellyfish and other Cnidarians are split into two groups, the protostomes and deuterostomes. Chordates are deuterostomes, it seems that the 555 million year old Kimberella was a member of the protostomes. That implies that the protostome and deuterostome lineages split some time before Kimberella appeared — at least 558 million years ago, hence well before the start of the Cambrian 541 million years ago, i.e. during the part of the Ediacaran Period.
The oldest discovered proposed deuterostome is Saccorhytus coronarius, which lived 540 million years ago. The researchers that made the discovery believe that the Saccorhytus is a common ancestor to all previously-known deuterostomes. Fossils of one major deuterostome group, the echinoderms, are quite common from the start of Series 2 of the Cambrian, 521 million years ago; the Mid Cambrian fossil Rhabdotubus johanssoni has been interpreted as a pterobranch hemichordate. Opinions differ about whether the Chengjiang fauna fossil Yunnanozoon, from the earlier Cambrian, was a hemichordate or chordate. Another Chengjiang fossil, Haikouella lanceolata from the Chengjiang fauna, is interpreted as a chordate and a craniate, as it shows signs of a heart, gill filaments, a tail, a neural chord with a brain at the front end, eyes — although it had short tentacles round its mouth. Haikouichthys and Myllokunmingia from the Chengjiang fauna, are regarded as fish. Pikaia, discovered much earlier but from the Mid Cambrian Burgess Shale, is regarded as a primitive chordate.
On the other hand, fossils of early chordates are rare, as non-vertebrate chordates have no bone tissue or teeth, fossils of no Post-Cambrian non-vertebrate chordates are known aside from the Permian-aged Paleobranchiostoma, trace fossils of the Ordovician colonial tunicate Catellocaula, various Jurassic-a
Margaret D. Stock is an immigration attorney based in Anchorage, a retired Lieutenant Colonel in the United States Army Reserve, she is a recognized expert on immigration law as it applies to US military veterans. She is a member of the Federalist Society. Stock is a 2013 recipient of a MacArthur Fellowship, she has taught law at the United States Military Academy in New York. She ran for the United States Senate as an Independent candidate in the 2016 Senate election in Alaska. Stock grew up in Wellesley, Massachusetts, she was the fourth of nine children. When she was six years old, her father had the first of several heart attacks, he died when she was 15; the family was in crisis, she spent time in a homeless shelter and a foster home. While in high school, she got involved the Civil Air Patrol but she dropped out of high school before graduating. A high school guidance counselor helped her gain admission to Boston University, where she enlisted in the Reserve Officer Training Corps, she completed paratrooper training at Fort Benning and transferred to Harvard.
Stock graduated from Harvard and Radcliffe Colleges in 1985. S. Army War College in 2006. Stock led the development of three programs pertaining to immigration issues within the US military; the Military accessions vital to national interest program, started in 2008, in cooperation with the Department of Defense and Department of Homeland Security, helped the U. S. armed forces to attract and retain foreign nationals with language and other skills critical to military readiness and national security. She spearheaded the American Immigration Lawyers Association MAP program, "which pairs volunteer attorneys across the United States" with military families in need of their services, she helped start the naturalization at Basic Combat Training program. Stock has spent many years teaching. From 2001–2010 she worked as a professor at the United States Military Academy at West Point first in the Department of Law in the Department of Social Sciences, she taught at University of Alaska Anchorage in the political science department for two years.
The Washington Times called her "the foremost authority on military veterans facing deportation."Stock has testified before Congress on issues involving immigration and national security. Running as an independent, Stock came in third in the 2016 U. S. Senate election, winning 13.2% of the vote 5,000 more than Democratic candidate Ray Metcalfe. 2013 – MacArthur Fellowship by John D. & Catherine T. MacArthur Foundation 2009 – Joint Service Commendation Medal by United States Armed Forces 2008 – Michael Maggio Pro Bono Award by American Immigration Lawyers Association 2005 – Advocacy Award by American Immigration Lawyers Association What Every Lawyer Needs to Know about Non-Citizens & the United States Military, in What Every Lawyer Needs to Know About Immigration Law, American Bar Association, Section of Administrative Law & Regulatory Practice. AILA's Guide to U. S. Citizenship & Naturalization Law, American Immigration Lawyers Association, 2014, at 153–182. Immigration Law and the Military. Professionals: A Matter of Degree.
The Role of Immigration in A Coordinated National Security Policy, 21 Georgetown Immigration Law Journal 383. Margaret Stock campaign website Washington Post interview – "MacArthur fellow Margaret Stock: The public ‘doesn’t understand’ illegal immigration"
The Musée de la civilisation à Québec is a museum located in Quebec City, Canada. It is situated in the historic Old Quebec area near the Saint Lawrence River, it was designed by architect Moshe Safdie, opened its doors to the public on 19 December 1988. The previous buildings of the Banque de Paris and the Maison Estèbe, which were situated on Saint-Pierre street, were integrated in the museum's structure. Permanent and temporary exhibitions are held at the museum related to humanities, virtual exhibitions are available; the institution hosts Quartier des découvertes, geared towards children, offers other services such as guided visits, a French America reference centre, souvenir boutiques, a cafeteria, a leisure room. Territoires Le Temps des Québécois Nous, les premières nations The Museum is affiliated with: the Canadian Museums Association, the Canadian Heritage Information Network, the Virtual Museum of Canada. Culture of Quebec List of museums in Quebec Musée de l'Amérique française Canadian Museum of Civilization in Hull, Quebec Official website Musée de la civilisation, Museums to Discover