Robert T. Bakker
Robert Thomas Bakker is an American paleontologist who helped reshape modern theories about dinosaurs by adding support to the theory that some dinosaurs were endothermic. Along with his mentor John Ostrom, Bakker was responsible for initiating the ongoing "dinosaur renaissance" in paleontological studies, beginning with Bakker's article "Dinosaur Renaissance" in the April 1975 issue of Scientific American, his special field is the ecological behavior of dinosaurs. Bakker has been a major proponent of the theory that dinosaurs were "warm-blooded," smart and adaptable, he published his first paper on dinosaur endothermy in 1968. His seminal work, The Dinosaur Heresies, was published in 1986, he revealed the first evidence of parental care at nesting sites for Allosaurus. He observed evidence in support of Eldredge and Gould's theory of punctuated equilibrium in dinosaur populations. Bakker serves as the Curator of Paleontology for the Houston Museum of Natural Science. Bakker was born in New Jersey.
He attributes his interest in dinosaurs to his reading an article in the September 7, 1953, issue of Life magazine. He graduated from Ridgewood High School in 1963. At Yale University, Bakker studied under John Ostrom, an early proponent of the new view of dinosaurs, gained a PhD at Harvard, he began by teaching anatomy at Johns Hopkins University in Baltimore and Earth and Space Sciences, where future artist Gregory S. Paul worked and collaborated informally under his guidance. Most of his field work has been done in Wyoming at Como Bluff, but he has ranged as far as Mongolia and South Africa in pursuit of dinosaur habitats, he helped as an assistant at the University of Colorado. In his 1986 work The Dinosaur Heresies, Bakker puts forth the theory that dinosaurs were warm-blooded, his evidence for this includes: Almost all animals that walk upright today are warm-blooded, dinosaurs walked upright. The hearts of warm-blooded animals can pump much more than the hearts of cold-blooded animals. Therefore, the giant Brachiosaurus must have had the type of heart associated with warm-blooded animals, in order to pump blood all the way up to its head.
Dinosaurs such as Deinonychus led a active life, much more compatible with a warm-blooded animal. Some dinosaurs lived in northern latitudes where it would have been impossible for cold-blooded dinosaurs to keep warm; the rapid rate of speciation and evolution found in dinosaurs is typical of warm blooded animals and atypical of cold blooded animals. The predator/prey ratio of predatory dinosaurs to their prey is a signature trait of warm-blooded predators rather than cold-blooded ones. Birds are warm-blooded. Birds evolved from dinosaurs, therefore a change to a warm-blooded metabolism must have taken place at some point. Warm-blooded metabolisms are evolutionary advantages for large herbivores. No such evidence exists. Dinosaurs grew evidence for which can be found by observing cross-sections of their bones. Warm-blooded animals grow at a similar rate. Bakker is a proponent of the idea that flowering plants evolved because of their interactions with dinosaurs, his novel Raptor Red tells of a year in the life of a female Utahraptor of the lower Cretaceous.
In the story, Bakker elaborates on his knowledge of the behavior of dromaeosaurids and life at the time of their existence. As a Pentecostal, Ecumenical Christian minister, Bakker has said there is no real conflict between religion and science, that evolution of species and geologic history is compatible with religious belief. Bakker views the Bible as an ethical and moral guide, rather than a literal timetable of events in the history of life, he has advised non-believers and creationists to read the views put forward by Saint Augustine, who argued against a literal understanding of the Book of Genesis. Bakker was advisor for the 1992 PBS series, The Dinosaurs!. He was among the advisors for the film Jurassic Park, with some of the early concept art being informed by Bakker's works. Bakker appeared in the Sega CD version of Jurassic Park. Dr. Bakker was a guest in episode 28 of the Williams Street original Space Ghost Coast to Coast. Bakker and his 1986 book are mentioned in the original Jurassic Park.
The bearded paleontologist Dr. Robert Burke, eaten by a Tyrannosaurus rex in Steven Spielberg's film The Lost World: Jurassic Park, is an affectionate caricature of Bakker. In real life, Bakker has argued for a predatory T. rex, while Bakker's rival paleontologist Jack Horner views it as a scavenger. According to Horner, Spielberg wrote the character of Burke and had him killed by the T. rex as a favor for Horner. After the film came out, Bakker recognized himself in Burke, loved the caricature, sent Horner a message saying, "See, I told you T. rex was a hunter!". Bakker, Robert T; the Dinosaur Heresies, William Morrow. Bakker, Robert T. Raptor Red, Bantam Books. Dinosaur renaissance Physiology of dinosaurs Robert T. Bakker on IMDb Robert Bakker, GeoCities, archived from the original on 2009-10-26. Bio article with information about his then-new book on creationism, Saint Augustine vs. evolution Photograph of Bakker at Como Bluff, Wyoming from "Discovering Dinosaurs" in the Encyclopædia Britannica
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles and archosaurs; the world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors; the Permian ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 96% of marine species and 70% of terrestrial species died out.
It would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian–Triassic extinction event was protracted; the term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Édouard de Verneuil; the region now lies in the Perm Krai of Russia. Official ICS 2017 subdivisions of the Permian System from most recent to most ancient rock layers are: Lopingian epoch Changhsingian Wuchiapingian Others: Waiitian Makabewan Ochoan Guadalupian epoch Capitanian stage Wordian stage Roadian stage Others: Kazanian or Maokovian Braxtonian stage Cisuralian epoch Kungurian stage Artinskian stage Sakmarian stage Asselian stage Others: Telfordian Mangapirian Sea levels in the Permian remained low, near-shore environments were reduced as all major landmasses collected into a single continent—Pangaea; this could have in part caused the widespread extinctions of marine species at the end of the period by reducing shallow coastal areas preferred by many marine organisms.
During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean, the Paleo-Tethys Ocean, a large ocean that existed between Asia and Gondwana; the Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic era. Large continental landmass interiors experience climates with extreme variations of heat and cold and monsoon conditions with seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea; such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees appeared in the Permian. Three general areas are noted for their extensive Permian deposits—the Ural Mountains and the southwest of North America, including the Texas red beds.
The Permian Basin in the U. S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world. The climate in the Permian was quite varied. At the start of the Permian, the Earth was still in an ice age. Glaciers receded around the mid-Permian period as the climate warmed, drying the continent's interiors. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles. Permian marine deposits are rich in fossil mollusks and brachiopods. Fossilized shells of two kinds of invertebrates are used to identify Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist, one of the foraminiferans, ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct. Terrestrial life in the Permian included diverse plants, fungi and various types of tetrapods; the period saw a massive desert covering the interior of Pangaea.
The warm zone spread in the northern hemisphere. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals became marginal elements; the Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began; the swamp-loving
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago. Reverse genetic engineering and the fossil record both demonstrate that birds are modern feathered dinosaurs, having evolved from earlier theropods during the late Jurassic Period; as such, birds were the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event 66 million years ago. Dinosaurs can therefore be divided into birds; this article deals with non-avian dinosaurs. Dinosaurs are a varied group of animals from taxonomic and ecological standpoints. Birds, at over 10,000 living species, are the most diverse group of vertebrates besides perciform fish. Using fossil evidence, paleontologists have identified over 500 distinct genera and more than 1,000 different species of non-avian dinosaurs.
Dinosaurs are represented on every continent by fossil remains. Through the first half of the 20th century, before birds were recognized to be dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction; some were herbivorous, others carnivorous. Evidence suggests that egg-laying and nest-building are additional traits shared by all dinosaurs and non-avian alike. While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage are small due to the constraints of flight, many prehistoric dinosaurs were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters and heights of 18 meters and were the largest land animals of all time.
Still, the idea that non-avian dinosaurs were uniformly gigantic is a misconception based in part on preservation bias, as large, sturdy bones are more to last until they are fossilized. Many dinosaurs were quite small: Xixianykus, for example, was only about 50 cm long. Since the first dinosaur fossils were recognized in the early 19th century, mounted fossil dinosaur skeletons have been major attractions at museums around the world, dinosaurs have become an enduring part of world culture; the large sizes of some dinosaur groups, as well as their monstrous and fantastic nature, have ensured dinosaurs' regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, new discoveries are covered by the media; the taxon'Dinosauria' was formally named in 1841 by paleontologist Sir Richard Owen, who used it to refer to the "distinct tribe or sub-order of Saurian Reptiles" that were being recognized in England and around the world.
The term is derived from Ancient Greek δεινός, meaning'terrible, potent or fearfully great', σαῦρος, meaning'lizard or reptile'. Though the taxonomic name has been interpreted as a reference to dinosaurs' teeth and other fearsome characteristics, Owen intended it to evoke their size and majesty. Other prehistoric animals, including pterosaurs, ichthyosaurs and Dimetrodon, while popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs; the other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida, except Dimetrodon. Under phylogenetic nomenclature, dinosaurs are defined as the group consisting of the most recent common ancestor of Triceratops and Neornithes, all its descendants, it has been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria. Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians, ceratopsians, ornithopods and sauropodomorphs.
Birds are now recognized as being the sole surviving lineage of theropod dinosaurs. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy. Birds are thus considered to be dinosaurs and dinosaurs are, not extinct. Birds are classified as belonging to the subgroup M
Physiology of dinosaurs
Preliminary note: In this article "dinosaur" means "non-avian dinosaur," since birds are a monophyletic taxon within the clade Dinosauria and most experts regard birds as dinosaurs. The physiology of dinosaurs has been a controversial subject their thermoregulation. Many new lines of evidence have been brought to bear on dinosaur physiology including not only metabolic systems and thermoregulation, but on respiratory and cardiovascular systems as well. During the early years of dinosaur paleontology, it was considered that they were sluggish and sprawling cold-blooded lizards. However, with the discovery of much more complete skeletons in western United States, starting in the 1870s, scientists could make more informed interpretations of dinosaur biology and physiology. Edward Drinker Cope, opponent of Othniel Charles Marsh in the Bone Wars, propounded at least some dinosaurs as active and agile, as seen in the painting of two fighting "Laelaps" produced under his direction by Charles R. Knight.
In parallel, the development of Darwinian evolution, the discoveries of Archaeopteryx and Compsognathus, led Thomas Henry Huxley to propose that dinosaurs were related to birds. Despite these considerations, the image of dinosaurs as large reptiles had taken root, most aspects of their paleobiology were interpreted as being reptilian for the first half of the twentieth century. Beginning in the 1960s and with the advent of the Dinosaur Renaissance, views of dinosaurs and their physiology have changed including the discovery of feathered dinosaurs in Early Cretaceous age deposits in China, indicating that birds evolved from agile maniraptoran dinosaurs; the study of dinosaurs began in the 1820s in England. Pioneers in the field, such as William Buckland, Gideon Mantell, Richard Owen, interpreted the first fragmentary remains as belonging to large quadrupedal beasts, their early work can be seen today in the Crystal Palace Dinosaurs, constructed in the 1850s, which present known dinosaurs as elephantine lizard-like reptiles.
Despite these reptilian appearances, Owen speculated that dinosaur heart and respiratory systems were more similar to that of a mammal than a reptile. In the late 1960s, similar ideas reappeared, beginning with John Ostrom's work on Deinonychus and bird evolution, his student, Bob Bakker, popularized the changing thought in a series of papers beginning with The superiority of dinosaurs in 1968. In these publications, he argued strenuously that dinosaurs were warm-blooded and active animals, capable of sustained periods of high activity. In most of his writings Bakker framed his arguments as new evidence leading to a revival of ideas popular in the late 19th century referring to an ongoing dinosaur renaissance, he used a variety of anatomical and statistical arguments to defend his case, the methodology of, fiercely debated among scientists. These debates sparked interest in new methods for ascertaining the palaeobiology of extinct animals, such as bone histology, which have been applied to determining the growth-rates of many dinosaurs.
Today, it is thought that many or all dinosaurs had higher metabolic rates than living reptiles, but that the situation is more complex and varied than Bakker proposed. For example, while smaller dinosaurs may have been true endotherms, the larger forms could have been inertial homeotherms, or that many dinosaurs could have had intermediate metabolic rates; the earliest dinosaurs were certainly predators, shared several predatory features with their nearest non-dinosaur relatives like Lagosuchus, including: large, blade-like teeth in large, wide-opening jaws that closed like scissors. Dinosaurs regarded as predators sometimes grew much larger, but retained the same set of features. Instead of chewing their food, these predators swallowed it whole; the feeding habits of ornithomimosaurs and oviraptorosaurs are a mystery: although they evolved from a predatory theropod lineage, they have small jaws and lack the blade-like teeth of typical predators, but there is no evidence of their diet or how they ate and digested it.
Features of other groups of dinosaurs indicate. These features include: Jaws that only opened and closed so that all the teeth met at the same time Large abdomens that could accommodate large amounts of vegetation and store it for the long time it takes to digest vegetation Guts that contained Endosymbiotic micro-organisms that digest cellulose, as no known animal can digest this tough material directlySauropods, which were herbivores, did not chew their food, as their teeth and jaws appear suitable only for stripping leaves off plants. Ornithischians herbivores, show a variety of approaches; the armored ankylosaurs and stegosaurs had small heads and weak jaws and teeth, are thought to have fed in much the same way as sauropods. The pachycephalosaurs had small heads and weak jaws and teeth, but their lack of large digestive systems suggests a different diet fruits, seeds, or young shoots, which would have been more nutritious to them than leaves. On the other hand, ornithopods such as Hypsilophodon and various hadrosaurs had horny beaks for snipping off vegetation and jaws and teeth that were well-adapted for chewing.
The horned ceratopsians had similar mechanisms. It has been suggested that at least some dinosaurs used swallowed stones, known as gastroliths, to aid digestion by grinding their food in muscular gizzards, that this was a feature they shared with birds. In 2007 Oliver Wings reviewed references to gastroliths in scientific literature an
Dicynodontia is a taxon of anomodont therapsids with beginnings in the mid-Permian, which were dominant in the Late Permian and continued throughout the Triassic, with a few surviving into the Early Cretaceous. Dicynodonts were herbivorous animals with two tusks, hence their name, which means'two dog tooth', they are the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat- to elephant-sized. The dicynodont skull is specialised, light but strong, with the synapsid temporal openings at the rear of the skull enlarged to accommodate larger jaw muscles; the front of the skull and the lower jaw are narrow and, in all but a number of primitive forms, toothless. Instead, the front of the mouth is equipped with a horny beak, as in turtles and ceratopsian dinosaurs. Food was processed by the retraction of the lower jaw when the mouth closed, producing a powerful shearing action, which would have enabled dicynodonts to cope with tough plant material.
Many genera have a pair of tusks, which it is thought may have been an example of sexual dimorphism. The body is short and barrel-shaped, with strong limbs. In large genera the hindlimbs were held erect. Both the pectoral girdle and the ilium are strong; the tail is short. Dicynodonts have long been suspected of being warm-blooded animals, their bones are vascularised and possess Haversian canals, their bodily proportions are conducive to heat preservation. In young specimens, the bones are so vascularised that they exhibit higher channel densities than most other therapsids. Yet, studies on Late Triassic dicynodont coprolites paradoxically showcase digestive patterns more typical of animals with slow metabolisms. More the discovery of hair remnants in Permian coprolites vindicates the status of dicynodonts as endothermic animals; as these coprolites come from carnivorous species and digested dicynodont bones are abundant, it has been suggested that at least some of these hair remnants come from dicynodont prey.
Pentasauropus dicynodont tracks suggest. Dicynodonts have been known since the mid-1800s; the South African geologist Andrew Geddes Bain gave the first description of dicynodonts in 1845. At the time, Bain was a supervisor for the construction of military roads under the Corps of Royal Engineers and had found many reptilian fossils during his surveys of South Africa. Bain described these fossils in an 1845 letter published in Transactions of the Geological Society of London, calling them "bidentals" for their two prominent tusks. In that same year, the English paleontologist Richard Owen named two species of dicynodonts from South Africa: Dicynodon lacerticeps and Dicynodon bainii. Since Bain was preoccupied with the Corps of Royal Engineers, he wanted Owen to describe his fossils more extensively. Owen did not publish a description until 1876 in his Descriptive and Illustrated Catalogue of the Fossil Reptilia of South Africa in the Collection of the British Museum. By this time, many more dicynodonts had been described.
In 1859, another important species called. A year in 1860, Owen named the group Dicynodontia. In his Descriptive and Illustrated Catalogue, Owen honored Bain by erecting Bidentalia as a replacement name for his Dicynodontia; the name Bidentalia fell out of use in the following years, replaced by popularity of Owen's Dicynodontia. Dicynodonts first appear during Middle Permian, underwent a rapid evolutionary radiation, becoming the most successful and abundant land vertebrates of the Late Permian. During this time, they included a large variety of ecotypes, including large, medium-sized, small herbivores and short-limbed mole-like burrowers. Only four lineages are known to have survived the end of Permian extinction. None of these survived long into the Triassic; the fourth group was the Kannemeyeriiformes, the only dicynodonts who diversified during the Triassic. These stocky, pig- to ox-sized animals were the most abundant herbivores worldwide from the Olenekian to the Ladinian age. By the Carnian they had been supplanted by traversodont cynodonts and rhynchosaur reptiles.
During the Norian due to increasing aridity, they drastically declined, the role of large herbivores was taken over by sauropodomorph dinosaurs. Fossils of an elephant-sized dicynodont Lisowicia bojani discovered in Poland indicate that dicynodonts survived at least until the late Norian or earliest Rhaetian. Six fragments of fossil bone interpreted as remains of a skull discovered in Australia might indicate that dicynodonts survived into the Cretaceous in southern Gondwana. However, Agnolin et al. considered the affinities of the specimen from Australia to be uncertain, noted its similarity to the skull bones of some baurusuchian crocodyliforms, such as Baurusuchus pachecoi. With the decline and extinction of the kannemeyerids, there were to be no more dominant large synapsid herbivores until the middle Paleocene epoch when mammals, descendants of cynodonts, began to diversify after the extinction of the non-avian dinosaurs. Dicynodontia was named by the English paleontologist Richard Owen.
It was erected as a family of the order Anomodontia and included the genera Dicynodon and Ptychognathus. Other groups of Anomodontia included Gnathodontia, which included Rhynchosaurus and Cryptodontia, which included
The Smithsonian Institution, founded on August 10, 1846 "for the increase and diffusion of knowledge," is a group of museums and research centers administered by the Government of the United States. The institution is named after British scientist James Smithson. Organized as the "United States National Museum," that name ceased to exist as an administrative entity in 1967. Termed "the nation's attic" for its eclectic holdings of 154 million items, the Institution's nineteen museums, nine research centers, zoo include historical and architectural landmarks located in the District of Columbia. Additional facilities are located in Arizona, Massachusetts, New York City, Texas and Panama. More than 200 institutions and museums in 45 states, Puerto Rico, Panama are Smithsonian Affiliates; the Institution's thirty million annual visitors are admitted without charge. Its annual budget is around $1.2 billion with two-thirds coming from annual federal appropriations. Other funding comes from the Institution's endowment and corporate contributions, membership dues, earned retail and licensing revenue.
Institution publications include Air & Space magazines. The British scientist James Smithson left most of his wealth to his nephew Henry James Hungerford; when Hungerford died childless in 1835, the estate passed "to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase & diffusion of knowledge among men", in accordance with Smithson's will. Congress accepted the legacy bequeathed to the nation, pledged the faith of the United States to the charitable trust on July 1, 1836; the American diplomat Richard Rush was dispatched to England by President Andrew Jackson to collect the bequest. Rush returned in August 1838 with 105 sacks containing 104,960 gold sovereigns. Once the money was in hand, eight years of Congressional haggling ensued over how to interpret Smithson's rather vague mandate "for the increase and diffusion of knowledge." The money was invested by the US Treasury in bonds issued by the state of Arkansas, which soon defaulted.
After heated debate, Massachusetts Representative John Quincy Adams persuaded Congress to restore the lost funds with interest and, despite designs on the money for other purposes, convinced his colleagues to preserve it for an institution of science and learning. On August 10, 1846, President James K. Polk signed the legislation that established the Smithsonian Institution as a trust instrumentality of the United States, to be administered by a Board of Regents and a Secretary of the Smithsonian. Though the Smithsonian's first Secretary, Joseph Henry, wanted the Institution to be a center for scientific research, it became the depository for various Washington and U. S. government collections. The United States Exploring Expedition by the U. S. Navy circumnavigated the globe between 1838 and 1842; the voyage amassed thousands of animal specimens, an herbarium of 50,000 plant specimens, diverse shells and minerals, tropical birds, jars of seawater, ethnographic artifacts from the South Pacific Ocean.
These specimens and artifacts became part of the Smithsonian collections, as did those collected by several military and civilian surveys of the American West, including the Mexican Boundary Survey and Pacific Railroad Surveys, which assembled many Native American artifacts and natural history specimens. In 1846, the regents developed a plan for weather observation; the Institution became a magnet for young scientists from 1857 to 1866, who formed a group called the Megatherium Club. The Smithsonian played a critical role as the U. S. partner institution in early bilateral scientific exchanges with the Academy of Sciences of Cuba. Construction began on the Smithsonian Institution Building in 1849. Designed by architect James Renwick Jr. its interiors were completed by general contractor Gilbert Cameron. The building opened in 1855; the Smithsonian's first expansion came with construction of the Arts and Industries Building in 1881. Congress had promised to build a new structure for the museum if the 1876 Philadelphia Centennial Exposition generated enough income.
It did, the building was designed by architects Adolf Cluss and Paul Schulze, based on original plans developed by Major General Montgomery C. Meigs of the United States Army Corps of Engineers, it opened in 1881. The National Zoological Park opened in 1889 to accommodate the Smithsonian's Department of Living Animals; the park was designed by landscape architect Frederick Law Olmsted. The National Museum of Natural History opened in June 1911 to accommodate the Smithsonian's United States National Museum, housed in the Castle and the Arts and Industries Building; this structure was designed by the D. C. architectural firm of Hornblower & Marshall. When Detroit philanthropist Charles Lang Freer donated his private collection to the Smithsonian and funds to build the museum to hold it, it was among the Smithsonian's first major donations from a private individual; the gallery opened in 1923. More than 40 years would pass before the next museum, the Museum of History and Technology, opened in 1964.
It was designed by the world-renowned firm of Mead & White. The Anacostia Community Museum, an "experimental store-front" museum created at the initiative of Smithsonian Secretary S. Dillon Ripley, opened in the Anacostia neighborhood of