A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature, a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae and plants and ICZN the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly Lycaeides idas longinus is a preserved specimen of that species, held by the Museum of Comparative Zoology at Harvard University. An isotype is a duplicate of the holotype and is made for plants, where holotype and isotypes are pieces from the same individual plant or samples from the same gathering. A holotype is not "typical" of that taxon, although ideally it should be. Sometimes just a fragment of an organism is the holotype in the case of a fossil.
For example, the holotype of Pelorosaurus humerocristatus, a large herbivorous dinosaur from the early Jurassic period, is a fossil leg bone stored at the Natural History Museum in London. If a better specimen is subsequently found, the holotype is not superseded. Under the ICN, an additional and clarifying type could be designated an epitype under Article 9.8, where the original material is demonstrably ambiguous or insufficient. A conserved type is sometimes used to correct a problem with a name, misapplied. In the absence of a holotype, another type may be selected, out of a range of different kinds of type, depending on the case, a lectotype or a neotype. For example, in both the ICN and the ICZN a neotype is a type, appointed in the absence of the original holotype. Additionally, under the ICZN the Commission is empowered to replace a holotype with a neotype, when the holotype turns out to lack important diagnostic features needed to distinguish the species from its close relatives. For example, the crocodile-like archosaurian reptile Parasuchus hislopi Lydekker, 1885 was described based on a premaxillary rostrum, but this is no longer sufficient to distinguish Parasuchus from its close relatives.
This made. Texan paleontologist Sankar Chatterjee proposed that a new type specimen, a complete skeleton, be designated; the International Commission on Zoological Nomenclature considered the case and agreed to replace the original type specimen with the proposed neotype. The procedures for the designation of a new type specimen when the original is lost come into play for some recent, high-profile species descriptions in which the specimen designated as the holotype was a living individual, allowed to remain in the wild. In such a case, there is no actual type specimen available for study, the possibility exists that—should there be any perceived ambiguity in the identity of the species—subsequent authors can invoke various clauses in the ICZN Code that allow for the designation of a neotype. Article 75.3.7 of the ICZN requires that the designation of a neotype must be accompanied by "a statement that the neotype is, or upon publication has become, the property of a recognized scientific or educational institution, cited by name, that maintains a research collection, with proper facilities for preserving name-bearing types, that makes them accessible for study", but there is no such requirement for a holotype.
Type Allotype Paratype Type species Genetypes- genetic sequence data from type specimens. BOA Photographs of type specimens of Neotropical Rhopalocera
Timeline of ornithology
The following is a timeline of ornithology events: 1500–800 BC – The Vedas mention the habit of brood parasitism in the Asian koel. 4th century BC – Aristotle mentions over 170 sorts of birds in his work on animals. He recognises eight principal groups. 3rd century BC – The Erya, a Chinese encyclopedia comprising glosses on passages in ancient texts, notably the Book of Songs, features 79 entries in its chapter "Describing Birds" 1st century AD – Pliny the Elder's Historia Naturalis Book X is devoted to birds. Three groups based on characteristics of feet 2nd century AD – Aelian mentions a number of birds in his work on animals. Birds are listed alphabetically 1037 Death of Abu ‘Ali al-Husayn ibn Abd Allah ibn Sina author of Abbreviatio de animalibus, a homage to Aristotle 1220 – Books on birds and other animals by Aristotle and Avicenna translated into Latin for the first time by Michael Scot 1250 – Death of Frederick II von Hohenstaufen, Holy Roman Emperor, author of de Arte Venandi cum Avibus that describes the first manipulative experiments in ornithology and the methods of falconry 1478 – De Avibus by Albertus Magnus is printed, which mentions many bird names for the first time 1485 – First dated copy of Ortus sanitatis by Johannes de Cuba 1544 – William Turner prints a commentary on the birds mentioned by Aristotle and Pliny 1555 – Conrad Gessner's Historic Animalium qui est de Auium natura and Pierre Belon's Histoire de la nature des Oyseaux.
Belon lists birds according to a definite system 1573 – Volcher Coiter publishes his first treatise on bird anatomy 1591 – Joris Hoefnagel starts to work for Rudolf II, Holy Roman Emperor and produces for him 90 oil-base paintings, of which one is of the dodo. 1596 – The Compendium of Chinese Materia Medica by Li Shizhen includes a total of 77 species of bird. 1600 – Beginning of the publication of the works of Ulisse Aldrovandi on birds. 1603 – Caspar Schwenckfeld publishes the first regional fauna of Europe: Therio-tropheum Silesiae. 1605 – Clusius publishes Exoticorum libri decem in which he describes many new exotic species. 1609 – The illustrated Sancai Tuhui, a Chinese encyclopedia by Wang Qi & Wang Siyi, lists a total of 113 species of bird. 1638 – Georg Marcgraf begins a voyage to Brazil where he studies the fauna and flora. 1652 – Leopoldina founded in the Holy Roman Empire. It is the oldest continuously existing learned society in the world. 1655 – Ole Worm collects a famous cabinet of curiosities whose illustrated inventory appears in 1655, Museum Wormianum.
This collection comprises many birds but the techniques of conservation are not successful and they are destroyed by insects. 1657 – Publication of Historiae naturalis de avibus by John Jonston. 1667 – Christopher Merrett publishes the first fauna of Great Britain, followed two years by that of Walter Charleton. 1676 – Publication of Francis Willughby's Ornithologia by his collaborator John Ray. This is considered the beginning of scientific ornithology in Europe, revolutionizing ornithological taxonomy by organizing species according to their physical characteristics 1681 – The last dodo dies on the island of Mauritius 1702 – Ferdinand Johann Adam von Pernau publishes a popular pioneering essay on bird behaviour. 1710 – Osservatorio Ornitologico di Arosio established 1713 – Death of the collector Johan de la Faille 1715 – Levinus Vincent publishes Wondertooneel der Nature the Wonder Theater of Nature 1716 – Peter the Great purchases the natural history collection of Albertus Seba 1724–1726 – François Valentijn and George Eberhard Rumpf give the first accounts of birds-of-paradise in Oud en Nieuw Oost-Indiën 1731–1738 Eleazar Albin publishes A Natural History of Birds 1731–1743 – Mark Catesby publishes his Natural History of Carolina, which contains coloured plates of the birds of that colony and the Bahamas 1733 – Great Northern Expedition leaves Saint Petersburg 1735 – Carl Linnaeus publishes his Systema Naturae.
The classification of birds follows that of Ray 1737 – Giuseppe Zinanni writes the first book devoted to the eggs and nests of birds, Dell Uova Nidi e dei degli Uccelli published in Venice 1741 – Georg Steller studies the birds of the north Pacific on his voyage with Vitus Bering 1742–1743 – Johann Heinrich Zorn publishes Petino-Theologie oder Versuch, Die Menschen durch nähere Betrachtung Der Vögel Zur Bewunderung Liebe und Verehrung ihres mächtigsten, weissest- und gütigsten Schöpffers aufzumuntern. Ornithotheology, or an encouragement to humanity, through a careful observation of birds, towards admiration and respect for their powerful, of the wise and good Creator. 1743 – George Edwards begins publication of his bird plates 1744 – Louisa Ulrika of Prussia becomes Queen of Sweden. She is a patron of Linnaeus. 1754 – Jean-Louis Alléon-Dulac publishes Mélange d'histoire naturelle 1756 – Wilhelm Heinrich Kramer publishes in Elenchus Vegetabilium et Animalium per Austriam inferiorem Observatorum 1756 – Louis Daniel Arnault de Nobleville publishes Histoire naturelle des animaux 1757 – Michel Adanson publishes Histoire naturelle du Senegal.
1759–1771 – Peter Ascanius Icones rerum naturalium 1760 – Mathurin Jacques Brisson's six-volume Ornithologie improves upon Linnaeus' classification 1763 – Erik Pontoppidan begins Den Danske atlas eller Konge-Riget Dannemark 1765 – Edme-Louis Daubenton engaged by Georges-Louis Leclerc, Comte de Buffon to supervise the illustration of his Histoire naturelle 1766–1769 French naturalist Philibert Commerçon accompanies Louis Antoine de Bougainville on a voyage of circumnavigation 1768–1780 – Voyages of James Cook to the Pacific and Australia during which many birds new to science are collected by Joseph Banks and Johann Reinhold Forster
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi
Loye H. Miller
Loye Holmes Miller, was an American paleontologist and zoologist who served as professor of zoology at the University of California, Los Angeles, University of California and University of California, Davis. Loye Miller was born in Minden, Louisiana, to parents George and Cora Holmes Miller and grew up in Riverside, California. Miller studied at the University of California, earning a B. A. in chemistry, an M. A. in zoology and Ph. D. in paleontology. He taught for three years at Oahu College in Honolulu before earning his master's degree, he was first instructor of biology at Los Angeles State Normal School, teaching from 1904 to 1919. He became a professor, retiring in 1943, his research included, among others. Fossil birds from Pleistocene caves in California, the La Brea Tar Pits, the Green River Formation in Oregon. With funding from the University Regents, he and John C. Merriam excavated La Brea from 1905 to 1907 and in 1912–1913. Miller was a fellow of the American Association for the Advancement of Science, American Ornithological Union, California Academy of Sciences.
He served as vice-president of the Society of Vertebrate Paleontology. He was awarded an honorary LL. D. by the University of California in 1951. Known as "Padre" to friends and colleagues, He supervised two Ph. D. students, two master's students, served on the dissertation committee of paleontologist Hildegarde Howard. Miller died April 6, 1970, in Davis, California, he was survived by three grandchildren and seven great grandchildren. His elder son Alden Holmes Miller, who died in 1965, was a professor of zoology at UC Berkeley, director of the Museum of Vertebrate Zoology; the Fossil Birds of California, an Avifauna and Bibliography with Annotations. University of California Publications in Zoology. 1942. Birds of the Campus, University of California Los Angeles. University of California Press. 1947. Lifelong Boyhood: Recollections of a Naturalist Afield. University of California Press. 1950. Loye Holmes Miller: The Interpretive Naturalist, University of California, Berkeley, 1970 Storer, Tracy I.. "Loye Holmes Miller: Un hombre muy simpatico".
The Condor. 74: 231–236. Doi:10.2307/1366586. JSTOR 1366586. Works by or about Loye H. Miller at Internet Archive Guide to the Loye Holmes Miller papers, 1899-1957 at the Bancroft Library, UC Berkeley
The Accipitriformes are an order of birds that includes most of the diurnal birds of prey – including hawks and vultures, but not falcons – about 217 species in all. For a long time, the majority view was to include them with the falcons in the Falconiformes, but many authorities now recognize a separate Accipitriformes. A DNA study published in 2008 indicated that falcons are not related to the Accipitriformes, being instead more related to parrots and passerines. Since the split and the placement of the falcons next to the parrots in taxonomic order has been adopted by the American Ornithological Society's South American Classification Committee, its North American Classification Committee, the International Ornithological Congress; the British Ornithologists' Union recognized the Accipitriformes, has adopted the move of Falconiformes. The DNA-based proposal and the NACC and IOC classifications include the New World vultures in the Accipitriformes, while the SACC classifies the New World vultures as a separate order, the Cathartiformes.
The Accipitriformes are known from the Middle Eocene and have a hooked beak with a soft cere housing the nostrils. Their wings are long and broad, suitable for soaring flight, with the outer four to six primary feathers emarginated, they have strong feet with raptorial claws and opposable hind claws. All Accipitriformes are carnivorous, hunting by sight during the day or at twilight, they are exceptionally long-lived, most have low reproductive rates. The young have a long fast-growing fledgling stage, followed by 3–8 weeks of nest care after first flight, 1 to 3 years as sexually immature adults; the sexes have conspicuously different sizes and sometimes a female is more than twice as heavy as her mate. This sexual dimorphism is sometimes most extreme in specialized bird-eaters, such as the Accipiter hawks, borders on nonexistent among the vultures. Monogamy is the general rule, although an alternative mate is selected if one dies. Order Accipitriformes For a complete list of species, see list of Accipitriformes.
Accipitridae Pandionidae Sagittariidae Chesser, R. T.. "Fifty-First Supplement to the American Ornithologists' Union Check-list of North American Birds". The Auk. 127: 726–744. Doi:10.1525/auk.2010.127.3.726. Chesser, R. Terry. "Fifty-Third Supplement to the American Ornithologists' Union Check-List of North American Birds". The Auk. 129: 573–588. Doi:10.1525/auk.2012.129.3.573. Full text via AOU, COPO, BioOne. Christidis, Les. Systematics and Taxonomy of Australian Birds. CSIRO Publishing. ISBN 978-0-643-06511-6. Retrieved 2010-01-14. Includes a review of recent literature on the controversy. Cramp, Stanley. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palearctic – Hawks to Bustards. Oxford University Press. Pp. 3, 277. ISBN 978-0-19-857505-4. Dudley, S. P.. "The British List: A Checklist of Birds of Britain". Ibis. 148: 526. Doi:10.1111/j.1474-919X.2006.00603.x. Ferguson-Lees, James. Raptors of the World. Illustrated by Kim Franklin, David Mead, Philip Burton. Houghton Mifflin.
ISBN 978-0-618-12762-7. Retrieved 2011-05-26. Gill, Frank. Worldbirdnames.org. Archived from the original on 24 March 2010. Retrieved 2010-03-12. Hackett, Shannon J.. "A phylogenomic study of birds reveals their evolutionary history". Science. 320: 1763–68. Doi:10.1126/science.1157704. PMID 18583609. Gill, Frank. "Updates". IOC World Bird List. Archived from the original on 2014-09-24. Retrieved 2014-09-30. Falconiformes was resequenced in Manuel. "Proposal to South American Classification Committee: Change linear sequence of orders for Falconiformes and Cariamiformes". Archived from the original on 2012-04-01. Retrieved 30 September 2014. Remsen, Van. "Proposal to South American Classification Committee: Separate Accipitriformes from Falconiformes". Archived from the original on 2010-06-28. Retrieved 30 September 2014. Remsen, J. V. Jr.. "A classification of the bird species of South America ". Version 11 December 2008. American Ornithologists' Union. Archived from the original on 12 April 2008. Retrieved 2010-05-26.
Sangster, G.. C.. "Taxonomic recommendations for Western Palearctic birds: Ninth report". Ibis. 155: 898. Doi:10.1111/ibi.12091. Voous, K. H.. "List of Recent Holarctic Bird Species Non-Passerines". Ibis. 115: 612–638. Doi:10.1111/j.1474-919X.1973.tb02004.x. Media related to Accipitriformes
Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s by Willard Libby, who received the Nobel Prize in Chemistry for his work in 1960, it is based on the fact that radiocarbon is being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14C combines with atmospheric oxygen to form radioactive carbon dioxide, incorporated into plants by photosynthesis; when the animal or plant dies, it stops exchanging carbon with its environment, from that point onwards the amount of 14C it contains begins to decrease as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died; the older a sample is, the less 14C there is to be detected, because the half-life of 14C is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods permit accurate analysis of older samples.
Research has been ongoing since the 1960s to determine what the proportion of 14C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms, the varying levels of 14C throughout the biosphere. Additional complications come from the burning of fossil fuels such as coal and oil, from the above-ground nuclear tests done in the 1950s and 1960s; because the time it takes to convert biological materials to fossil fuels is longer than the time it takes for its 14C to decay below detectable levels, fossil fuels contain no 14C, as a result there was a noticeable drop in the proportion of 14C in the atmosphere beginning in the late 19th century. Conversely, nuclear testing increased the amount of 14C in the atmosphere, which attained a maximum in about 1965 of twice what it had been before the testing began.
Measurement of radiocarbon was done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample. More accelerator mass spectrometry has become the method of choice; the development of radiocarbon dating has had a profound impact on archaeology. In addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances. Histories of archaeology refer to its impact as the "radiocarbon revolution". Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, the beginning of the Neolithic and Bronze Age in different regions. In 1939, Martin Kamen and Samuel Ruben of the Radiation Laboratory at Berkeley began experiments to determine if any of the elements common in organic matter had isotopes with half-lives long enough to be of value in biomedical research, they synthesized 14C using the laboratory's cyclotron accelerator and soon discovered that the atom's half-life was far longer than had been thought.
This was followed by a prediction by Serge A. Korff employed at the Franklin Institute in Philadelphia, that the interaction of thermal neutrons with 14N in the upper atmosphere would create 14C, it had been thought that 14C would be more to be created by deuterons interacting with 13C. At some time during World War II, Willard Libby, at Berkeley, learned of Korff's research and conceived the idea that it might be possible to use radiocarbon for dating. In 1945, Libby moved to the University of Chicago, he published a paper in 1946 in which he proposed that the carbon in living matter might include 14C as well as non-radioactive carbon. Libby and several collaborators proceeded to experiment with methane collected from sewage works in Baltimore, after isotopically enriching their samples they were able to demonstrate that they contained 14C. By contrast, methane created from petroleum showed no radiocarbon activity because of its age; the results were summarized in a paper in Science in 1947, in which the authors commented that their results implied it would be possible to date materials containing carbon of organic origin.
Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages. For example, two samples taken from the tombs of two Egyptian kings and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years; these results were published in Science in 1949. Within 11 years of their announcement, more than 20 radiocarbon dating laboratories had been set up worldwide. In 1960, Libby was awarded the Nobel Prize in Chemistry for this work. In nature, carbon exists as two stable, nonradioactive isotopes: carbon-12, carbon-13, a radioactive isotope, carbon-14 known as "radiocarbon"; the half-life