Paleontology or palaeontology is the scientific study of life that existed prior to, sometimes including, the start of the Holocene Epoch. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments. Paleontological observations have been documented as far back as the 5th century BC; the science became established in the 18th century as a result of Georges Cuvier's work on comparative anatomy, developed in the 19th century. The term itself originates from Greek παλαιός, palaios, "old, ancient", ὄν, on, "being, creature" and λόγος, logos, "speech, study". Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of anatomically modern humans, it now uses techniques drawn from a wide range of sciences, including biochemistry and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life all the way back to when Earth became capable of supporting life, about 3.8 billion years ago.
As knowledge has increased, paleontology has developed specialised sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates. Body fossils and trace fossils are the principal types of evidence about ancient life, geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave body fossils. Estimating the dates of these remains is essential but difficult: sometimes adjacent rock layers allow radiometric dating, which provides absolute dates that are accurate to within 0.5%, but more paleontologists have to rely on relative dating by solving the "jigsaw puzzles" of biostratigraphy. Classifying ancient organisms is difficult, as many do not fit well into the Linnaean taxonomy classifying living organisms, paleontologists more use cladistics to draw up evolutionary "family trees"; the final quarter of the 20th century saw the development of molecular phylogenetics, which investigates how organisms are related by measuring the similarity of the DNA in their genomes.
Molecular phylogenetics has been used to estimate the dates when species diverged, but there is controversy about the reliability of the molecular clock on which such estimates depend. The simplest definition of paleontology is "the study of ancient life"; the field seeks information about several aspects of past organisms: "their identity and origin, their environment and evolution, what they can tell us about the Earth's organic and inorganic past". Paleontology is one of the historical sciences, along with archaeology, astronomy, cosmology and history itself: it aims to describe phenomena of the past and reconstruct their causes. Hence it has three main elements: description of past phenomena; when trying to explain the past and other historical scientists construct a set of hypotheses about the causes and look for a smoking gun, a piece of evidence that accords with one hypothesis over the others. Sometimes the smoking gun is discovered by a fortunate accident during other research. For example, the discovery by Luis and Walter Alvarez of iridium, a extra-terrestrial metal, in the Cretaceous–Tertiary boundary layer made asteroid impact the most favored explanation for the Cretaceous–Paleogene extinction event, although the contribution of volcanism continues to be debated.
The other main type of science is experimental science, said to work by conducting experiments to disprove hypotheses about the workings and causes of natural phenomena. This approach cannot prove a hypothesis, since some experiment may disprove it, but the accumulation of failures to disprove is compelling evidence in favor. However, when confronted with unexpected phenomena, such as the first evidence for invisible radiation, experimental scientists use the same approach as historical scientists: construct a set of hypotheses about the causes and look for a "smoking gun". Paleontology lies between biology and geology since it focuses on the record of past life, but its main source of evidence is fossils in rocks. For historical reasons, paleontology is part of the geology department at many universities: in the 19th and early 20th centuries, geology departments found fossil evidence important for dating rocks, while biology departments showed little interest. Paleontology has some overlap with archaeology, which works with objects made by humans and with human remains, while paleontologists are interested in the characteristics and evolution of humans as a species.
When dealing with evidence about humans and paleontologists may work together – for example paleontologists might identify animal or plant fossils around an archaeological site, to discover what the people who lived there ate. In addition, paleontology borrows techniques from other sciences, including biology, ecology, chemistry and mathematics. For example, geochemical signatures from rocks may help to discover when life first arose on Earth, analyses of carbon isotope ratios may help to identify climate changes and to explain major transitions such as the Permian–Triassic extinction event. A recent discipline, molecular phylogenetics, compares the DNA and RNA of modern organisms to re-construct the "family trees" of their
Adam Sedgwick was a British geologist and priest, one of the founders of modern geology. He proposed the Devonian period of the geological timescale. Based on work which he did on Welsh rock strata, he proposed the Cambrian period in 1835, in a joint publication in which Roderick Murchison proposed the Silurian period. In 1840, to resolve what became known as the Great Devonian Controversy about rocks near the boundary between the Silurian and Carboniferous periods, he and Murchison proposed the Devonian period. Though he had guided the young Charles Darwin in his early study of geology and continued to be on friendly terms, Sedgwick was an opponent of Darwin's theory of evolution by means of natural selection. Sedgwick was born in Dent, the third child of an Anglican vicar, he was educated at Trinity College, Cambridge. He studied mathematics and theology, obtained his BA from the University of Cambridge in 1808 and his MA in 1811. On July 20, 1817 he was ordained a deacon a year he was ordained as a priest.
His academic mentors at Cambridge were John Dawson. He became a Fellow of Trinity College and Woodwardian Professor of Geology at Cambridge from 1818, holding the chair until his death in 1873, his biography in the Cambridge Alumni database says that upon his acceptance of the position, reverend Sedgwick had no working knowledge of geology. An 1851 portrait of Sedgwick by William Boxall hangs in Trinity's collection. Sedgwick studied the geology of the British Isles and Europe, he founded the system for the classification of Cambrian rocks and with Roderick Murchison worked out the order of the Carboniferous and underlying Devonian strata. These studies were carried out in the 1830s; the investigations into the Devonian meant that Sedgwick was involved with Murchison in a vigorous debate with Henry De la Beche, in what became known as the great Devonian controversy. Sedgwick investigated the phenomena of metamorphism and concretion, was the first to distinguish between stratification and slaty cleavage.
He was elected to Fellow of the Royal Society on 1 February 1821. In 1844, he was elected a Foreign Honorary Member of the American Academy of Sciences; as a co-trustee of the will of Ann Sill, an owner of slaves in plantations in Jamaica, in 1835 Sedgwick was awarded half of £3783 in compensation for 174 slaves, following the abolition of slavery by the British government. A liberal Whig in politics, Sedgwick had long been a passionate supporter of abolition; the Church of England, by no means a fundamentalist or evangelical church, encloses a wide range of beliefs. During Sedgwick's life there developed something of a chasm between the conservative high church believers and the liberal wing. After simmering for some years, the publication of Essays and Reviews by liberal churchmen in 1860 pinpointed the differences. In all this, whose science and faith were intertwined in a natural theology, was on the conservative side, outspoken about it, he told the February 1830 meeting of the Geological Society of London: "No opinion can be heretical, but that, not true....
Conflicting falsehoods we can comprehend. I affirm, that we have nothing to fear from the results of our enquiries, provided they be followed in the laborious but secure road of honest induction. In this way we may rest assured that we shall never arrive at conclusions opposed to any truth, either physical or moral, from whatever source that truth may be derived"; as a geologist in the mid-1820s he supported William Buckland's interpretation of certain superficial deposits loose rocks and gravel, as "diluvium" relating to worldwide floods, in 1825 he published two papers identifying these as due to a "great irregular inundation" from the "waters of a general deluge", Noah's flood. Sedgwick's subsequent investigations and discussions with continental geologists persuaded him that this was problematic. In early 1827, after spending several weeks in Paris, he visited geological features in the Scottish Highlands with Roderick Murchison, he wrote "If I have been converted in part from the diluvian theory...it was...by my own gradual improved experience, by communicating with those about me.
I may date my change of mind from our journey in the Highlands, where there are so many indications of local diluvial operations.... Humboldt ridiculed beyond measure. Prévost lectured against it." In response to Charles Lyell's 1830 publication, Principles of Geology, known for promoting uniformitarian geology Sedgwick talked of floods at various dates on 18 February 1831 when retiring from the Presidency of the Geological Society he recanted his former belief in Buckland's theory. He believed that species of organisms originated in a succession of Divine creative acts throughout the long expanse of history. Any form of development that denied a direct creative action smacked as amoral. For Sedgwick, moral truths were to be distinguished from physical truths, to combine these or blur them together could only lead to disastrous consequences. In fact, one's own hope for immortality may rest on it, he stated in 1830 that Scriptural geologists proposed "a deformed progeny of heretical and fantastical conclusions, by which sober philosophy has been put to open shame, sometimes the charities of life have been exposed to violation."
In 1834 he continued, "They have committed the folly and SIN of dogmatizing," having "sinned against plain sense," and "of
The public domain consists of all the creative works to which no exclusive intellectual property rights apply. Those rights may have been forfeited, expressly waived, or may be inapplicable; the works of William Shakespeare and Beethoven, most early silent films, are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by copyright, are therefore in the public domain—among them the formulae of Newtonian physics, cooking recipes, all computer software created prior to 1974. Other works are dedicated by their authors to the public domain; the term public domain is not applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as "under license" or "with permission". As rights vary by country and jurisdiction, a work may be subject to rights in one country and be in the public domain in another; some rights depend on registrations on a country-by-country basis, the absence of registration in a particular country, if required, gives rise to public-domain status for a work in that country.
The term public domain may be interchangeably used with other imprecise or undefined terms such as the "public sphere" or "commons", including concepts such as the "commons of the mind", the "intellectual commons", the "information commons". Although the term "domain" did not come into use until the mid-18th century, the concept "can be traced back to the ancient Roman Law, as a preset system included in the property right system." The Romans had a large proprietary rights system where they defined "many things that cannot be owned" as res nullius, res communes, res publicae and res universitatis. The term res nullius was defined as things not yet appropriated; the term res communes was defined as "things that could be enjoyed by mankind, such as air and ocean." The term res publicae referred to things that were shared by all citizens, the term res universitatis meant things that were owned by the municipalities of Rome. When looking at it from a historical perspective, one could say the construction of the idea of "public domain" sprouted from the concepts of res communes, res publicae, res universitatis in early Roman law.
When the first early copyright law was first established in Britain with the Statute of Anne in 1710, public domain did not appear. However, similar concepts were developed by French jurists in the 18th century. Instead of "public domain", they used terms such as publici juris or propriété publique to describe works that were not covered by copyright law; the phrase "fall in the public domain" can be traced to mid-19th century France to describe the end of copyright term. The French poet Alfred de Vigny equated the expiration of copyright with a work falling "into the sink hole of public domain" and if the public domain receives any attention from intellectual property lawyers it is still treated as little more than that, left when intellectual property rights, such as copyright and trademarks, expire or are abandoned. In this historical context Paul Torremans describes copyright as a, "little coral reef of private right jutting up from the ocean of the public domain." Copyright law differs by country, the American legal scholar Pamela Samuelson has described the public domain as being "different sizes at different times in different countries".
Definitions of the boundaries of the public domain in relation to copyright, or intellectual property more regard the public domain as a negative space. According to James Boyle this definition underlines common usage of the term public domain and equates the public domain to public property and works in copyright to private property. However, the usage of the term public domain can be more granular, including for example uses of works in copyright permitted by copyright exceptions; such a definition regards work in copyright as private property subject to fair-use rights and limitation on ownership. A conceptual definition comes from Lange, who focused on what the public domain should be: "it should be a place of sanctuary for individual creative expression, a sanctuary conferring affirmative protection against the forces of private appropriation that threatened such expression". Patterson and Lindberg described the public domain not as a "territory", but rather as a concept: "here are certain materials – the air we breathe, rain, life, thoughts, ideas, numbers – not subject to private ownership.
The materials that compose our cultural heritage must be free for all living to use no less than matter necessary for biological survival." The term public domain may be interchangeably used with other imprecise or undefined terms such as the "public sphere" or "commons", including concepts such as the "commons of the mind", the "intellectual commons", the "information commons". A public-domain book is a book with no copyright, a book, created without a license, or a book where its copyrights expired or have been forfeited. In most countries the term of protection of copyright lasts until January first, 70 years after the death of the latest living author; the longest copyright term is in Mexico, which has life plus 100 years for all deaths since July 1928. A notable exception is the United States, where every book and tale published prior to 1924 is in the public domain.
Crimea is a peninsula on the northern coast of the Black Sea in Eastern Europe, completely surrounded by both the Black Sea and the smaller Sea of Azov to the northeast. It is located south of the Ukrainian region of Kherson, to which it is connected by the Isthmus of Perekop, west of the Russian region of Kuban, from which it is separated by the Strait of Kerch though linked by the Crimean Bridge; the Arabat Spit is located to the northeast, a narrow strip of land that separates a system of lagoons named Sivash from the Sea of Azov. Across the Black Sea to its west is Romania and to its south Turkey. Crimea has been at the boundary between the classical world and the Pontic–Caspian steppe, its southern fringe was colonised by the Greeks, the Persians, the Romans, the Byzantine Empire, the Crimean Goths, the Genoese and the Ottoman Empire, while at the same time its interior was occupied by a changing cast of invading steppe nomads and empires, such as the Cimmerians, Sarmatians, Alans, Huns, Kipchaks and the Golden Horde.
Crimea and adjacent territories were united in the Crimean Khanate during the 15th to 18th century. In 1783, Crimea became a part of the Russian Empire as the result of the Russo-Turkish War. Following the Russian Revolution of 1917, Crimea became an autonomous republic within the Russian Soviet Federative Socialist Republic in the USSR. During World War II, Crimea was downgraded to the Crimean Oblast after its entire indigenous population, the Crimean Tatars, were deported to Central Asia, an act recognized as a genocide. In 1954, it was transferred to the Ukrainian SSR from the Russian SFSR. With the collapse of the Soviet Union, Ukraine was formed as an independent state in 1991 and most of the peninsula was reorganized as the Autonomous Republic of Crimea, while the city of Sevastopol retained its special status within Ukraine; the 1997 Partition Treaty on the Status and Conditions of the Black Sea Fleet partitioned the former Soviet Black Sea Fleet and allowed Russia to continue basing its fleet in Crimea: both the Ukrainian Naval Forces and Russian's Black Sea Fleet were to be headquartered in Sevastopol.
Ukraine extended Russia's lease of the naval facilities under the 2010 Kharkiv Pact in exchange for further discounted natural gas. In February 2014, following the 2014 Ukrainian revolution that ousted the Ukrainian President, Viktor Yanukovych, pro-Russian separatists and Russian Armed Forces took over the territory. A controversial Crimea-wide referendum, unconstitutional under the Ukrainian and Crimean constitutions, was held on the issue of reunification with Russia which official results indicated was supported by a large majority of Crimeans. Russia formally annexed Crimea on 18 March 2014, incorporating the Republic of Crimea and the federal city of Sevastopol as the 84th and 85th federal subjects of Russia; the classical name Tauris or Taurica is from the Greek Ταυρική, after the peninsula's Scytho-Cimmerian inhabitants, the Tauri. Strabo and Ptolemy refer variously to the Strait of Kerch as the Κιμμερικὸς Βόσπορος, its easternmost part as the Κιμμέριον Ἄκρον (Kimmerion Akron, Roman name: Promontorium Cimmerium, as well as to the city of Cimmerium and whence the name of the Kingdom of the Cimmerian Bosporus.
The earliest recorded use of the toponym “Crimea” for the peninsula occurred between 1315-1329 AD by the Arab writer Abū al-Fidā where he recounts a political fight in 1300-1301 AD resulting in a rival's decapitation and having “sent his head to the Crimea”. The Crimean Tatar name of the peninsula is Qırım and so for the city of Krym, now called Stary Krym which served as a capital of the Crimean province of the Golden Horde; some sources hold that the name of the capital was extended to the entire peninsula at some point during Ottoman suzerainty. The origin of the word Qırım is uncertain. Suggestions argued in various sources: a corruption of Cimmerium. A derivation from the Turkic term qirum, from qori-. Other suggestions either unsupported or contradicted by sources based on similarity in sound, include: a derivation from the Greek Cremnoi. However, Herodotus identifies the port not in Crimea, but as being on the west coast of the Sea of Azov. No evidence has been identified that this name was in use for the peninsula.
The Turkic term is related to the Mongolian appellation kerm "wall", but sources indicate that the Mongolian appellation of the Crimean peninsula of Qaram is phonetically incompatible with kerm/kerem and therefore deriving from another original term. The name "Crimea" is the Italian form, i.e. la Crimea, since at least the 17th century and the "Crimean peninsula" becomes current during the 18th century replacing the classical name of Tauric Peninsula in the course of the 19th century. In English usage since the early modern period the Crimean Khanate is referred to as Crim Tartary; the omission of the definite article in English became common during the 20th century. The classical name was used in 1802 in the name of the Russian
Brachiopods, phylum Brachiopoda, are a group of lophotrochozoan animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection. Two major groups are recognized and inarticulate; the word "articulate" is used to describe the tooth-and-groove features of the valve-hinge, present in the articulate group, absent from the inarticulate group. This is the leading diagnostic feature, by which the two main groups can be distinguished. Articulate brachiopods have toothed hinges and simple opening and closing muscles, while inarticulate brachiopods have untoothed hinges and a more complex system of muscles used to keep the two valves aligned. In a typical brachiopod a stalk-like pedicle projects from an opening in one of the valves near the hinges, known as the pedicle valve, keeping the animal anchored to the seabed but clear of silt that would obstruct the opening.
The word "brachiopod" is formed from podos. They are known as "lamp shells", since the curved shells of the class Terebratulida look rather like pottery oil-lamps. Lifespans range from three to over thirty years. Ripe gametes float from the gonads into the main coelom and exit into the mantle cavity; the larvae of inarticulate brachiopods are miniature adults, with lophophores that enable the larvae to feed and swim for months until the animals become heavy enough to settle to the seabed. The planktonic larvae of articulate species do not resemble the adults, but rather look like blobs with yolk sacs, remain among the plankton for only a few days before leaving the water column upon metamorphosing. In addition to the traditional classification of brachiopods into inarticulate and articulate, two approaches appeared in the 1990s: one approach groups the inarticulate Craniida with articulate brachiopods, since both use the same material in the mineral layers of their shell. However, some taxonomists believe it is premature to suggest higher levels of classification such as order and recommend a bottom-up approach that identifies genera and groups these into intermediate groups.
Traditionally, brachiopods have been regarded as members of, or as a sister group to, the deuterostomes, a superphylum that includes chordates and echinoderms. One type of analysis of the evolutionary relationships of brachiopods has always placed brachiopods as protostomes while another type has split between placing brachiopods among the protostomes or the deuterostomes, it was suggested in 2003 that brachiopods had evolved from an ancestor similar to Halkieria, a slug-like Cambrian animal with "chain mail" on its back and a shell at the front and rear end. However, new fossils found in 2007 and 2008 showed that the "chain mail" of tommotiids formed the tube of a sessile animal. Lineages of brachiopods that have both fossil and extant taxa appeared in the early Cambrian and Carboniferous periods, respectively. Other lineages have arisen and become extinct, sometimes during severe mass extinctions. At their peak in the Paleozoic era, the brachiopods were among the most abundant filter-feeders and reef-builders, occupied other ecological niches, including swimming in the jet-propulsion style of scallops.
Brachiopod fossils have been useful indicators of climate changes during the Paleozoic. However, after the Permian–Triassic extinction event, brachiopods recovered only a third of their former diversity. A study in 2007 concluded the brachiopods were vulnerable to the Permian–Triassic extinction, as they built calcareous hard parts and had low metabolic rates and weak respiratory systems, it was thought that brachiopods went into decline after the Permian–Triassic extinction, were out-competed by bivalves, but a study in 1980 found both brachiopod and bivalve species increased from the Paleozoic to modern times, with bivalves increasing faster. Brachiopods live only in the sea, most species avoid locations with strong currents or waves; the larvae of articulate species settle in and form dense populations in well-defined areas while the larvae of inarticulate species swim for up to a month and have wide ranges. Brachiopods now live in cold water and low light. Fish and crustaceans seem to find brachiopod flesh distasteful and attack them.
Among brachiopods, only the lingulids have been fished commercially, on a small scale. One brachiopod species may be a measure of environmental conditions around an oil terminal being built in Russia on the shore of the Sea of Japan. Modern brachiopods range from 1 to 100 millimetres long, most species are about 10 to 30 millimetres; the largest brachiopods known – Gigantoproductus and Titanaria, reaching 30 to 38 centimetres in width – occurred in the upper part of the Lower Carboniferous. Each has two valves which cover the dorsal and ventral surface of the animal, unlike bivalve molluscs whose shells cover the lateral surfaces; the valves are t
Système universitaire de documentation
The système universitaire de documentation or SUDOC is a system used by the libraries of French universities and higher education establishments to identify and manage the documents in their possession. The catalog, which contains more than 10 million references, allows students and researcher to search for bibliographical and location information in over 3,400 documentation centers, it is maintained by the Bibliographic Agency for Higher Education. Official website