In situ is a Latin phrase that translates literally to on site or in position. It means locally, on site, on the premises or in place to describe an event where it takes place, in the aerospace industry, equipment on-board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may work but interference from nearby equipment may create unanticipated problems, special test equipment is available for this in situ testing. In archaeology, in situ refers to an artifact that has not been moved from its place of deposition. In other words, it is stationary, meaning still, an artifact being in situ is critical to the interpretation of that artifact and, consequently, of the culture which formed it. Once an artifacts find-site has been recorded, the artifact can be moved for conservation, further interpretation, an artifact that is not discovered in situ is considered out of context and as not providing an accurate picture of the associated culture.
However, the out of context artifact can provide scientists with an example of types, when excavating a burial site or surface deposit in situ refers to cataloging, mapping, photographing human remains in the position they are discovered. The label in situ indicates only that the object has not been newly moved. Thus, an archaeological in situ find may be an object that was looted from another place, an item of booty of a past war. Consequently, the in situ find site may not reveal its provenance. It is possible for archaeological layers to be reworked on purpose or by accident, for example, in a Tell mound, where layers are not typically uniform or horizontal, or in land cleared or tilled for farming. The term in situ is used to describe ancient sculpture that was carved in place such as the Sphinx or Petra. This distinguishes it from statues that were carved and moved like the Colossi of Memnon, which was moved in ancient times. In art, in situ refers to a work of art made specifically for a host site, for a more detailed account see, Site-specific art.
The term can refer to a work of art created at the site where it is to be displayed, rather than one created in the artists studio. In architectural sculpture the term is employed to describe sculpture that is carved on a building, frequently from scaffolds. A fraction of the star clusters in our galaxy, as well as those in other massive galaxies. The rest might have been accreted from now defunct dwarf galaxies, in biology and biomedical engineering, in situ means to examine the phenomenon exactly in place where it occurs
The klipspringer is a small antelope found in eastern and southern Africa. The sole member of its genus, the klipspringer was first described by German zoologist Eberhard August Wilhelm von Zimmermann in 1783, the klipspringer is a small, sturdy antelope, it reaches 43–60 centimetres at the shoulder and weighs from 8 to 18 kilograms. The coat of the klipspringer, yellowish gray to reddish brown, unlike most other antelopes, the klipspringer has a thick and coarse coat with hollow, brittle hairs. The horns and spiky, present only on males, typically nocturnal, the klipspringer rests during the middle of the day and late at night. A gregarious animal, the klipspringer is monogamous to a greater extent than other antelopes. The mates tend to stay as close as within 5 metres of each other at most times, males form territories,7. 5–49 hectares, in which they stay with their partners and offspring. Primarily a browser, the klipspringer prefers young plants, gestation lasts around six months, following which a single calf is born, births peak from spring to early summer.
The calf leaves its mother when it turns a year old, the klipspringer inhabits places characterised by rocky terrain and sparse vegetation. Its range extends from northeastern Sudan, northern Somalia and Ethiopia in the east to South Africa in the south, the International Union for the Conservation of Nature and Natural Resources classifies the klipspringer as Least Concern. There are no threats to the survival of the klipspringer. Significant numbers occur on private farmlands, as of 2008, nearly 25% of the populations occur in protected areas throughout its range. The scientific name of the klipspringer is Oreotragus oreotragus and it is the sole member of the genus Oreotragus and classified under the family Bovidae. The species was first described by German zoologist Eberhard August Wilhelm von Zimmermann in 1783, the vernacular name klipspringer is a compound of the Afrikaans words klip and springer. Another name for this antelope is klipbok, a 2012 phylogenetic study showed that the klipspringer is closely related to Kirks dik-dik and the suni.
The klipspringer evolved nearly 14 million years ago, the cladogram below is based on this study. The head-and-body length is typically between 75 and 115 centimetres and it weighs from 8 to 18 kilograms. The klipspringer is sexually dimorphic, females are larger and heavier than the males. Prominent facial features include the brown forehead, short ears marked with black, prominent preorbital glands near the eyes, the horns and spiky, present only on males, typically measure 7. 5–9 centimetres, the maximum recorded horn length is 15.9 centimetres
It is situated within the Cradle of Humankind World Heritage Site and is itself a South African National Heritage Site. Gladysvale is the first cave that Robert Broom visited in the Transvaal in his mid-1930s search for a hominid-bearing cave nearer to Johannesburg than Taung and he visited Gladysvale after a butterfly collector from the Transvaal Museum reported a human mandible in the wall of the cave. When Broom arrived at the cave the mandible was gone, sterkfontein soon lured Broom away from the site. In 1946 Phillip Tobias led a student expedition to the site where a fine baboon fossil was recovered, in 1948 Frank Peabody of the Camp-Peabody expedition from the United States spent several weeks at Gladysvale but failed to find any hominid remains. The site was lost from scientific memory until it was re-opened by Lee Berger, within a few weeks of excavation the first hominid remains were discovered – two teeth of Australopithecus africanus. This discovery made Gladysvale the first new hominid site to be discovered in South Africa since 1948.
Many thousands of fossils have been recovered from the Gladysvale deposits including rare remains of hominids, from the Gladysvale external deposits, almost a quarter of a million bones have been recovered since excavations began in 1992. There are many millions of bones still in place in the cave, fossils recovered include antelope, giant zebra, carnivores including extinct wolves and hominids attributed to Australopithecus africanus and early Homo. Tools have found with the most spectacular being an Acheulean handaxe. The site is divided into three underground cave systems with the upper cave holding the Gladysvale Internal Deposits and an External Deposit. Gladysvale was one of the first sites in Africa to be 3-D digitally mapped by Peter Schmid, the Gladysvale sequence has been dated using a combination of biostratigraphy, electron spin resonance and uranium series dating. The youngest deposits are thought to be around 54,000 years old while the oldest deposits that are the source of the Au. africanus fossils are around 2. 4–2.0 million years old.
The Gladysvale External deposits contain extensive faunal remains and date to between 780,000 and 530,000 years ago, an Acheulian handaxe was recovered from internal deposits older than the Bruhnes-Matuyama boundary at 780,000 years. Media related to Gladysvale Cave at Wikimedia Commons The Gladysvale Homepage
University of the Witwatersrand
The University of the Witwatersrand, Johannesburg, is a multi-campus South African public research university situated in the northern areas of central Johannesburg. It is more known as Wits University. The university has its roots in the industry, as do Johannesburg. It was desegregated once again prior to the abolition of apartheid in 1990, several of apartheids most provocative critics, of either European or African descent, were one-time students and graduates of the university. The university has an enrolment of 33,711 students as of 2015,65 percent of the universitys total enrolment is for undergraduate study, with the remaining 35 percent being postgraduate. The university was founded in Kimberley in 1896 as the South African School of Mines, eight years later, in 1904, the school was moved to Johannesburg and renamed the Transvaal Technical Institute. The schools name changed yet again in 1906 to Transvaal University College, in 1908, a new campus of the Transvaal University College was established in Pretoria.
The Johannesburg and Pretoria campuses separated on 17 May 1910, each becoming a separate institution, in 1920, the school was renamed the University College, Johannesburg. Finally, on 1 March 1922, the University College, was granted university status after being incorporated as the University of the Witwatersrand. The Johannesburg municipality donated a site in Milner Park, north-west of Braamfontein, to the new institution as its campus and construction began the same year, on 4 October. True to Hofmeyrs words, from the outset Wits was a university with a policy of non-discrimination on racial or any other grounds. Initially, there were six faculties—Arts, Medicine, Engineering and Commerce—37 departments,73 academic staff, and approximately 1,000 students. In 1923, the university began moving into the new campus, slowly vacating its former premises on Ellof Street for the first completed building in Milner Park, in 1925, the Prince of Wales officially opened Central Block. The universitys first library, housed at the time in what was meant to be a construction, was destroyed in a fire on Christmas Eve in 1931.
Following this, an appeal was made to the public for ₤80,000 to pay for the construction of a new library, and this resulted in the fairly rapid construction of the William Cullen Library, completed in 1935. During this period, as the Great Depression hit South Africa, nonetheless, it continued to grow at an impressive rate. From a total enrolment of 2,544 students in 1939 and this growth led to accommodation problems, which were temporarily resolved by the construction of wood and galvanised-iron huts in the centre of the campus. During World War II, Wits was involved in South Africas war efforts, the Bernard Price Institute of Geophysical Research was placed under the Union of South Africas defence ministry, and was involved in important research into the use of radar
Banded iron formation
Banded iron formations are distinctive units of sedimentary rock that are almost always of Precambrian age. Some of the oldest known rock formations, formed over 3,700 million years ago, Banded layers rich in iron were mostly deposited between 2,400 and 1,900 mya. Phanerozoic ironstones generally have a different genesis, Banded iron beds are an important commercial source of iron ore, such as the Pilbara region of Western Australia and the Animikie Group in Minnesota. The formations are abundant around the time of the great event,2,400 million years ago. The conventional concept is that the banded iron layers were formed in sea water as the result of oxygen released by photosynthetic cyanobacteria. The oxygen combined with dissolved iron in Earths oceans to form insoluble iron oxides, which precipitated out, forming a layer on the ocean floor. Each band is similar to a varve, to the extent that the banding is assumed to result from variations in available oxygen. It is unclear whether these banded ironstone formations were seasonal, followed some feedback oscillation in the complex system or followed some other cycle.
It is assumed that initially the Earth started with vast amounts of iron, as photosynthetic organisms generated oxygen, the available iron in the Earths oceans precipitated out as iron oxides. An alternative explanation of these deposits has undergone much discussion as part of the Snowball Earth hypothesis. Several hypotheses exist for the initiation of the Snowball Earths, in a Snowball Earth state the earths continents, and possibly seas at low latitudes, were subject to an ice age. If this was the case, Earths free oxygen may have nearly or totally depleted during a severe ice age circa 750 to 580 million years ago. Dissolved iron accumulated in the oxygen-poor oceans, following the thawing of the Earth, the seas became oxygenated once more causing the precipitation of the iron. Another mechanism for BIFs, proposed in the context of the Snowball Earth discussion, is by deposition from metal-rich brines in the vicinity of hydrothermally active rift zones, some geochemists suggest that BIFs could form by direct oxidation of iron by microbial anoxygenic phototrophs.
Northern Minnesotas banded iron formations lie directly underneath a layer of material only recently recognized as ejecta from the Sudbury Basin impact. At the time of formation Earth had a single supercontinent called Columbia with substantial continental shelves, an asteroid slammed into waters about 1,000 m deep some 1.85 billion years ago. Computer models suggest that the tsunami would have been at least 1,000 m at the epicentre and those immense waves and large underwater landslides triggered by the impact stirred the ocean, bringing oxygenated waters from the surface down to the ocean floor. Sediments deposited on the seafloor before the impact, including BIFs contained little if any oxidized iron and this Fe to Fe ratio suggests that most parts of the ocean were relatively devoid of oxygen
Malapa Fossil Site, Cradle of Humankind
It is situated within the Cradle of Humankind World Heritage Site. At the beginning of project, there were approximately 130 known cave sites in the region. Included in this were more than 25 fossil sites that had been unknown to science, Berger brought in geologist Paul Dirks, at that time Head of the School of GeoSciences at the University of the Witwatersrand, to lead the geological aspects of this exploratory project. On 1 August he dropped off Prof. Dirks to map the recognized cave system and proceeded into the area with his dog Tau. Almost immediately he discovered a fossil site that was unknown to science. On 15 August, Prof. Berger returned to the site with his student, Dr. Job Kibii. Within minutes, Matthew had discovered the first remains of human ancestors - a clavicle. On the opposite side of the block Prof. Berger quickly discovered a jawbone with a tooth of a hominid. The find would soon be prepared and identified as part of a skeleton of a juvenile hominid. On 4 September 2008, Berger returned to the site more than a dozen colleagues where Berger discovered a second partial skeleton of an adult female.
Over 200 elements have been recovered to date, the partial skeletons are initially described in two papers in the journal Science by Berger and colleagues as a new species of early human ancestor called Australopithecus sediba. The species has long arms, like an ape, short powerful hands, the skeletons are found among the articulated skeletons of a sabre-toothed cat and even mice and hares. It is not known how these skeletons came to be in this pool, no carnivores or scavengers reached their bodies. The fossil was dated using a combination of palaeomagnetism and uranium-lead dating by Andy Herries, Robyn Pickering, u-Pb dating of the underlying flowstone indicates that the fossils are not older than 2.0 Ma. The occurrence of species of animal became extinct at ~1.5 Ma indicate the deposit is not younger than 1.5 Ma. In 2011 a more accurate date of the fossils was established when a capping flowstone was too old to enable the normal polarity deposits to date to the Olduvai event. The deposits were instead correlated to a year long period centred at around 1.977 Ma.
List of fossil sites Free Images and resources about Australopithecus sediba and Malapa for Educators and Students
Elisabeth S. Vrba is a paleontologist at Yale University. Vrba earned her Ph. D. in Zoology and Palaeontology at the University of Cape Town and she is well known for developing the Turnover Pulse Hypothesis, as well as coining the word exaptation with colleague Stephen Jay Gould. Her specific interest is in the Family Bovidae, but her current graduate students are studying a range of species. She has been a faculty member at the Department of Geology & Geophysics, Yale University and she is married and has a daughter. She is renowned as both a researcher and a teacher and her teaching practises and personality were written about by a student named Roberto Rozzi. Vrba and colleague Stephen Jay Gould are renowned for their theory of exaptation, genetic adaptations may take on new functions and may serve a species a different purpose further on in evolution. Vrba constructed the turnover-pulse hypothesis, a significant addition to Macroevolutionary theory, Gould, S. J. and S. Vrba. Exaptation—a missing term in the science of form, evolving Vocabulary, the rise and fall of exaptation International Innovation, September 18,2015, http, //www. internationalinnovation. com/evolving-vocabulary-the-rise-and-fall-of-exaptation/.
Lewis, R. Surveying the Genomic Landscape of Modern Mammals, DNA Science Blog, exaptation of the Guitar Guitar International, September 17,2010, http, //guitarinternational. com/2010/09/17/exaptation-of-the-guitar/. More Evidence on the Real Nature of Evolutionary DNA Change, Huffington Post, The Blog, shell, E. R. Waves of Creation. Vrba, E. S. and Gould, S. J, the hierarchical expansion of sorting and selection
Fossils are the preserved remains or traces of animals and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record. The study of fossils across geological time, how they were formed, such a preserved specimen is called a fossil if it is older than some minimum age, most often the arbitrary date of 10,000 years. The observation that fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of dating techniques in the early 20th century allowed geologists to determine the numerical or absolute age of the various strata. Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs, Fossils may consist of the marks left behind by the organism while it was alive, such as animal tracks or feces.
These types of fossil are called trace fossils, as opposed to body fossils, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals, these are known as chemofossils or biosignatures. The process of fossilization varies according to type and external conditions. Permineralization is a process of fossilization that occurs when an organism is buried, the empty spaces within an organism become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces and this process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils, for permineralization to occur, the organism must become covered by sediment soon after death or soon after the initial decay process. The degree to which the remains are decayed when covered determines the details of the fossil, some fossils consist only of skeletal remains or teeth, other fossils contain traces of skin, feathers or even soft tissues.
This is a form of diagenesis, in some cases the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold, if this hole is filled with other minerals, it is a cast. An endocast or internal mold is formed when sediments or minerals fill the cavity of an organism. This is a form of cast and mold formation. If the chemistry is right, the organism can act as a nucleus for the precipitation of minerals such as siderite, if this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization, replacement occurs when the shell, bone or other tissue is replaced with another mineral
The Pliocene Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years BP. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era, the Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch.588 to 1.806 million years ago, and is now included in the Pleistocene. As with other geologic periods, the geological strata that define the start and end are well identified but the exact dates of the start. The boundaries defining the Pliocene are not set at an easily identified worldwide event, the upper boundary was set at the start of the Pleistocene glaciations. The Pliocene was named by Sir Charles Lyell, the name comes from the Greek words πλεῖον and καινός and means roughly continuation of the recent, referring to the essentially modern marine mollusc faunas. H. W. Fowler called the term a regrettable barbarism, in the official timescale of the ICS, the Pliocene is subdivided into two stages. From youngest to oldest they are, Piacenzian Zanclean The Piacenzian is sometimes referred to as the Late Pliocene, in the system of North American Land Mammal Ages include Hemphillian, and Blancan.
The Blancan extends forward into the Pleistocene, South American Land Mammal Ages include Montehermosan and Uquian. In the Paratethys area the Pliocene contains the Dacian and Romanian stages, as usual in stratigraphy, there are many other regional and local subdivisions in use. In Britain the Pliocene is divided into the stages, Waltonian, Pre-Ludhamian, Thurnian, Bramertonian or Antian, Pre-Pastonian or Baventian and Beestonian. The exact correlations between these stages and the ICS stages is still a matter of detail. The formation of an Arctic ice cap is signaled by a shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic. Mid-latitude glaciation was probably underway before the end of the epoch, the global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas. Continents continued to drift, moving from positions possibly as far as 250 km from their present locations to positions only 70 km from their current locations, africas collision with Europe formed the Mediterranean Sea, cutting off the remnants of the Tethys Ocean.
The border between the Miocene and the Pliocene is the time of the Messinian salinity crisis, Sea level changes exposed the land-bridge between Alaska and Asia. Pliocene marine rocks are exposed in the Mediterranean, India. Elsewhere, they are exposed largely near shores, the change to a cooler, seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide. Deciduous forests proliferated, coniferous forests and tundra covered much of the north, tropical forests were limited to a tight band around the equator, and in addition to dry savannahs, deserts appeared in Asia and Africa
Members of the human clade, that is, the Hominina, including Homo and those species of the australopithecines that arose after the split from the chimpanzees, are called homininans. Not all homininans are directly related to the emergence of early Homo and this is a modern cladogram, For each clade, the cladogram above shows approximately when newer extant clades emerged. Some texts refer to Homonini as the Hominina branch, the subtribe Hominina is the human branch, that is, it contains only the genus Homo. Researchers proposed the taxon Hominini on the basis that the least similar species of a trichotomy should be separated from the other two. The common chimpanzee and the bonobo of the genus Pan are the closest living relatives to humans. All the extinct genera listed to the right are ancestral to, or offshoots of, both Orrorin and Sahelanthropus existed around the time of the split, and so may be ancestral to both Pan and Homo. In the proposal of Mann and Weiss, the tribe Hominini includes Pan as well as Homo and all bipedal apes are referred to the subtribe Hominina, while Pan is assigned to the subtribe Panina.
Wood discusses the different views of this taxonomy, the assumption of late hybridization was in particular based on the similarity of the X chromosome in humans and chimpanzees, suggesting a divergence as late as some 4 million years ago. Sahelanthropus tchadensis is an extinct species that lived seven million years ago. Human Timeline – Smithsonian, National Museum of Natural History
The genus is between 2 and 3 million years old, taken to emerge with the appearance of Homo habilis. It is derived from the genus Australopithecus, which itself had previously split from the lineage of Pan, Homo is the only genus assigned to the subtribe Hominina which, with the subtribes Australopithecina and Panina, comprise the tribe Hominini. All species of the genus Homo plus those species of the australopithecines that arose after the split from Pan are called hominins, Homo erectus appeared about two million years ago in East Africa and, in several early migrations, it spread throughout Africa and Eurasia. It was likely the first hominin to live in a hunter-gatherer society, the subspecies Homo sapiens sapiens or anatomically modern humans emerged about 200,000 years ago in East Africa. DNA analysis provides evidence of interbreeding between archaic and modern humans. See Hominidae for an overview of taxonomy, the Latin noun homō means human being or man in the generic sense of human being, mankind.
The binomial name Homo sapiens was coined by Carl Linnaeus, names for other species of the genus were introduced beginning in the second half of the 19th century. Even today, the genus Homo has not been properly defined, since the early human fossil record began to slowly emerge from the earth, the boundaries and definitions of the genus Homo have been poorly defined and constantly in flux. Because there was no reason to think it would ever have any additional members, the discovery of Neanderthal brought the first addition. The genus Homo was given its name to suggest that its member species can be classified as human. Many such names are now dubbed as synonyms with Homo, including Pithecanthropus, Sinanthropus, Africanthropus, Atlanthropus, classifying the genus Homo into species and subspecies is subject to incomplete information and remains poorly done. Some recently extinct species in the genus Homo are only recently discovered, john Edward Gray was an early advocate of classifying taxa by designating tribes and families.
Several species, including Australopithecus garhi, Australopithecus sediba, Australopithecus africanus and these species have morphological features that align them with Homo, but there is no consensus as to which gave rise to Homo. The advent of Homo was traditionally taken to coincide with the first use of stone tools, the emergence of Homo coincides roughly with the onset of Quaternary glaciation, the beginning of the current ice age. A fossil mandible fragment dated to 2.8 million years ago which may represent a stage between Australopithecus and Homo was discovered in 2015 in Afar, Ethiopia. Some authors would push the development of Homo past 3 Mya, the most salient physiological development between the earlier australopithecine species and Homo is the increase in cranial capacity, from about 450 cm3 in A. garhi to 600 cm3 in H. habilis. Within the genus Homo, cranial capacity again doubled from H. habilis through Homo ergaster or H. erectus to Homo heidelbergensis by 0.6 million years ago, the cranial capacity of H. heidelbergensis overlaps with the range found in modern humans.
Homo erectus has often been assumed to have developed anagenetically from Homo habilis from about 2 million years ago