Cerebral Rubicon
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Cerebral Rubicon
A "cerebral rubicon" in paleontology is the minimum cranial capacity required for a specimen to be classified as a certain paleospecies or genus. The term is mostly used in reference to human evolution. The Scottish anthropologist Sir Arthur Keith set the limit at 750 cc for the genus ''Homo''. The minimum cranial capacity for the species Homo sapiens is generally set at 900cc. One of the reasons for the proposal to exclude ''Homo habilis'' from the genus ''Homo'', and renaming it as "''Australopithecus habilis''", is the small capacity of their cranium (363cc -600 cc). Origin The term is most likely a reference to the Rubicon river, which in the time of the Roman Empire marked the border between Cisapline Gaul and Italy proper. Crossing the river with an army, as Julius Caesar did in 49 B.C., was illegal by Roman law and is commonly seen as the "point-of-no-return" for Caesar's revolution. As such, a "rubicon" can be used idiomatically as any strict dividing line or point-o ...
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Cranial Capacity
The size of the brain is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Brain size is sometimes measured by weight and sometimes by volume (via MRI scans or by skull volume). Neuroimaging intelligence testing can be used to study the volumetric measurements of the brain. Regarding "intelligence testing", a question that has been frequently investigated is the relation of brain size to intelligence. This question is quite controversial and will be addressed further in the section on intelligence. The measure of brain size and cranial capacity is not just important to humans, but to all mammals. Humans In humans, the right cerebral hemisphere is typically larger than the left, whereas the cerebellar hemispheres are typically closer in size. The adult human brain weighs on average about . In men the average weight is about 1370 g and in women about 1200 g. The volume is around 1260  cm3 in men and 1130 &nbs ...
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Paleospecies
A chronospecies is a species derived from a sequential development pattern that involves continual and uniform changes from an extinct ancestral form on an evolutionary scale. The sequence of alterations eventually produces a population that is physically, morphologically, and/or genetically Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ... distinct from the original ancestors. Throughout the change, there is only one species in the lineage at any point in time, as opposed to cases where divergent evolution produces contemporary species with a common ancestor. The related term paleospecies (or palaeospecies) indicates an extinct species only identified with fossil material. That identification relies on distinct similarities between the earlier fossil specimens and some proposed d ...
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Arthur Keith
Sir Arthur Keith FRS FRAI (5 February 1866 – 7 January 1955) was a British anatomist and anthropologist, and a proponent of scientific racism. He was a fellow and later the Hunterian Professor and conservator of the Hunterian Museum of the Royal College of Surgeons of England. He was a strong proponent of Piltdown Man, but finally conceded it to be a forgery shortly before his death. Career A leading figure in the study of human fossils, he became President of the Royal Anthropological Institute. The latter role stimulated his interest in the subject of human evolution, leading to the publication of his book ''A New Theory of Human Evolution,'' in which he supported the idea of group selection. Where others had postulated that physical separation could provide a barrier to interbreeding, allowing groups to evolve along different lines, Keith introduced the idea of cultural differences as providing a mental barrier, emphasising territorial behaviour, and the concept of the 'i ...
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Homo Sapiens
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically mod ...
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Homo Habilis
''Homo habilis'' ("handy man") is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.31 million years ago to 1.65 million years ago (mya). Upon species description in 1964, ''H. habilis'' was highly contested, with many researchers recommending it be synonymised with '' Australopithecus africanus'', the only other early hominin known at the time, but ''H. habilis'' received more recognition as time went on and more relevant discoveries were made. By the 1980s, ''H. habilis'' was proposed to have been a human ancestor, directly evolving into '' Homo erectus'' which directly led to modern humans. This viewpoint is now debated. Several specimens with insecure species identification were assigned to ''H. habilis'', leading to arguments for splitting, namely into "''H. rudolfensis''" and "'' H. gautengensis''" of which only the former has received wide support. Like contemporary ''Homo'', ''H. habilis'' brain size generally varied from . ...
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Rubicon
The Rubicon ( la, Rubico; it, Rubicone ; rgn, Rubicôn ) is a shallow river in northeastern Italy, just north of Rimini. It was known as Fiumicino until 1933, when it was identified with the ancient river Rubicon, famously crossed by Julius Caesar in 49 BC. The river flows for around from the Apennine Mountains to the Adriatic Sea through the south of the Emilia-Romagna region, between the towns of Rimini and Cesena. History The Latin word comes from the adjective , meaning "red". The river was so named because its waters are colored red by iron deposits in the riverbed. During the Roman Republic, the Rubicon marked the boundary between the Roman province of Cisalpine Gaul and Italy proper, controlled directly by Rome and its (allies), to the south. On the north-western side, the border was marked by the river Arno, a much wider and more important waterway, which flows westward from the Apennine Mountains (the Arno and the Rubicon rise not far from each other) into the T ...
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Roman Empire
The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterranean Sea in Europe, North Africa, and Western Asia, and was ruled by emperors. From the accession of Caesar Augustus as the first Roman emperor to the military anarchy of the 3rd century, it was a Principate with Italia as the metropole of its provinces and the city of Rome as its sole capital. The Empire was later ruled by multiple emperors who shared control over the Western Roman Empire and the Eastern Roman Empire. The city of Rome remained the nominal capital of both parts until AD 476 when the imperial insignia were sent to Constantinople following the capture of the Western capital of Ravenna by the Germanic barbarians. The adoption of Christianity as the state church of the Roman Empire in AD 380 and the fall of the Western ...
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Gaul
Gaul ( la, Gallia) was a region of Western Europe first described by the Romans. It was inhabited by Celtic and Aquitani tribes, encompassing present-day France, Belgium, Luxembourg, most of Switzerland, parts of Northern Italy (only during Republican era, Cisalpina was annexed in 42 BC to Roman Italy), and Germany west of the Rhine. It covered an area of . According to Julius Caesar, Gaul was divided into three parts: Gallia Celtica, Belgica, and Aquitania. Archaeologically, the Gauls were bearers of the La Tène culture, which extended across all of Gaul, as well as east to Raetia, Noricum, Pannonia, and southwestern Germania during the 5th to 1st centuries BC. During the 2nd and 1st centuries BC, Gaul fell under Roman rule: Gallia Cisalpina was conquered in 204 BC and Gallia Narbonensis in 123 BC. Gaul was invaded after 120 BC by the Cimbri and the Teutons, who were in turn defeated by the Romans by 103 BC. Julius Caesar finally subdued the remaining parts of ...
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Julius Caesar
Gaius Julius Caesar (; ; 12 July 100 BC – 15 March 44 BC), was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war, and subsequently became dictator from 49 BC until his assassination in 44 BC. He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire. In 60 BC, Caesar, Crassus and Pompey formed the First Triumvirate, an informal political alliance that dominated Roman politics for several years. Their attempts to amass power as were opposed by the within the Roman Senate, among them Cato the Younger with the frequent support of Cicero. Caesar rose to become one of the most powerful politicians in the Roman Republic through a string of military victories in the Gallic Wars, completed by 51 BC, which greatly extended Roman territory. During this time he both invaded Britain and built a b ...
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Idiom
An idiom is a phrase or expression that typically presents a figurative, non-literal meaning attached to the phrase; but some phrases become figurative idioms while retaining the literal meaning of the phrase. Categorized as formulaic language, an idiom's figurative meaning is different from the literal meaning. Idioms occur frequently in all languages; in English alone there are an estimated twenty-five million idiomatic expressions. Derivations Many idiomatic expressions were meant literally in their original use, but sometimes the attribution of the literal meaning changed and the phrase itself grew away from its original roots—typically leading to a folk etymology. For instance, the phrase "spill the beans" (meaning to reveal a secret) is first attested in 1919, but has been said to originate from an ancient method of voting by depositing beans in jars, which could be spilled, prematurely revealing the results. Other idioms are deliberately figurative. For example, "break ...
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Microcephaly
Microcephaly (from New Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it may develop in the first few years of life. Since brain growth is correlated with head growth, people with this disorder often have an intellectual disability, poor motor function, poor speech, abnormal facial features, seizures and dwarfism. The disorder is caused by a disruption to the genetic processes that form the brain early in pregnancy, though the cause is not identified in most cases. Many genetic syndromes can result in microcephaly, including chromosomal and single-gene conditions, though almost always in combination with other symptoms. Mutations that result solely in microcephaly (primary microcephaly) exist but are less common. External toxins to the embryo, such as alcohol during pregnancy or vertically transmitted infec ...
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