1.
Hominidae
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Several revisions in classifying the great apes have caused the use of the term hominid to vary over time. Its original meaning referred only to humans and their closest non-extant relatives and that restrictive meaning has now been largely assumed by the term hominin, which comprises all members of the human clade after the split from the chimpanzees. The current, 21st-century meaning of hominid includes all the great apes including humans, the most recent common ancestor of all Hominidae lived roughly 14 million years ago, when the ancestors of the orangutans speciated from the ancestral line of the other three genera. Those ancestors of the family Hominidae had already speciated from the family Hylobatidae, in the early Miocene, about 22 million years ago, there were many species of arboreally adapted primitive catarrhines from East Africa, the variety suggests a long history of prior diversification. Fossils at 20 million years ago include fragments attributed to Victoriapithecus, the most recent of these far-flung Miocene apes is Oreopithecus, from the fossil-rich coal beds in northern Italy and dated to 9 million years ago. Species close to the last common ancestor of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus found in Greece. Molecular evidence suggests that between 8 and 4 million years ago, first the gorillas, and then the split off from the line leading to the humans. Human DNA is approximately 98. 4% identical to that of chimpanzees when comparing single nucleotide polymorphisms, the earliest fossils argued by some to belong to the human lineage are Sahelanthropus tchadensis and Orrorin tugenensis, followed by Ardipithecus, with species Ar. kadabba and Ar. ramidus. The classification of the apes has been revised several times in the last few decades. The original meaning of the referred to only humans and their closest relatives—what is now the modern meaning of the term hominin. And the meaning of the taxon Hominidae changed gradually, leading to a different usage of hominid that today all the great apes including humans. A hominid is a member of the family Hominidae, the apes, orangutans, gorillas, chimpanzees. A hominine is a member of the subfamily Homininae, gorillas, chimpanzees, a hominin is a member of the tribe Hominini, Chimpanzees and humans. A homininan is a member of the subtribe Hominina of the tribe Hominini, a human is a member of the genus Homo, of which Homo sapiens is the only extant species, and within that Homo sapiens sapiens is the only surviving subspecies. For each clade it is indicated approximately when newer extant clades emerged, some texts will refer to Homonini as the Hominina branch. Many scientists, including paleoanthropologists, continue to use the term hominid to mean humans, as mentioned, Hominidae was originally the name given to the family of humans and their close relatives, with the other great apes all being placed in a separate family, the Pongidae. However, that eventually made Pongidae paraphyletic because at least one great ape species proved to be more closely related to humans than to other great apes. Most taxonomists today encourage monophyletic groups—this would require, in this case, thus, many biologists now assign Pongo to the family Hominidae
2.
Homininae
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Homininae is a subfamily of Hominidae. It includes two tribes, with their extant as well as species, the Hominini tribe. It comprises all hominids that arose after orangutans split from the line of great apes, the Homininae cladogram has three main branches, which lead to gorillas, and to humans and chimpanzees via the tribe Hominini and subtribes Hominina and Panina. There are two living species of Panina and two living species of gorillas, but only one extant human species, traces of hypothetical Homo species, including Homo floresiensis and Homo denisova, have been found with dates as recent as 12,000 years ago. Organisms in this class are described as hominine or hominines, until 1980, the family Hominidae meant humans only, the non-human great apes were assigned to the family Pongidae. The subfamily Homininae can be subdivided into three branches, the tribe Gorillini, and the tribe Hominini with subtribes Panina and Hominina. Their existence suggests that the Homininae tribes diverged not earlier than about 8 million years ago, today, chimpanzees and gorillas live in tropical forests with acid soils that rarely preserve fossils. This shows that some chimpanzees lived close to Homo at the time, australopithecus and early Paranthropus may have been bipedal. Very early hominins such as Ardipithecus ramidus may have possessed a type of bipedalism. It is proposed that they evolved from H. erectus as a case of insular dwarfism, in spite of their smaller brain, there is evidence that H. floresiensis used fire and made stone tools at least as sophisticated as those of their proposed ancestors H. erectus. In this case, it seems that for intelligence, the structure of the brain is more important than its size, sexuality is related to family structure and partly shapes it. The involvement of fathers in education is unique to humans. Concealed ovulation and menopause in women both also occur in a few other primates however, but are uncommon in other species, testis and penis size seems to be related to family structure, monogamy or promiscuity, or harem, in humans, chimpanzees or gorillas, respectively. The levels of sexual dimorphism are seen as a marker of sexual selection. Concealed ovulation means that the phase of fertility is not detectable in women, women can be partly aware of their ovulation along the menstrual phases, but men are essentially unable to detect ovulation in women. Menopause also occurs in rhesus monkeys, and possibly in chimpanzees, chimpanzee-human last common ancestor List of human evolution fossils Human Timeline – Smithsonian, National Museum of Natural History
3.
Homo
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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, taxonomically, 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, Protanthropus, Sinanthropus, Cyphanthropus, Africanthropus, Telanthropus, 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 also 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
4.
Megaannum
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A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earths axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the globe, four seasons are recognized, spring, summer, autumn. In tropical and subtropical regions several geographical sectors do not present defined seasons, but in the seasonal tropics, a calendar year is an approximation of the number of days of the Earths orbital period as counted in a given calendar. The Gregorian, or modern, calendar, presents its calendar year to be either a common year of 365 days or a year of 366 days, as do the Julian calendars. For the Gregorian calendar the average length of the year across the complete leap cycle of 400 years is 365.2425 days. The ISO standard ISO 80000-3, Annex C, supports the symbol a to represent a year of either 365 or 366 days, in English, the abbreviations y and yr are commonly used. In astronomy, the Julian year is a unit of time, it is defined as 365.25 days of exactly 86400 seconds, totalling exactly 31557600 seconds in the Julian astronomical year. The word year is used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year. Similarly, year can mean the period of any planet, for example. The term can also be used in reference to any long period or cycle, west Saxon ġēar, Anglian ġēr continues Proto-Germanic *jǣran. Cognates are German Jahr, Old High German jār, Old Norse ár and Gothic jer, all the descendants of the Proto-Indo-European noun *yeh₁rom year, season. Cognates also descended from the same Proto-Indo-European noun are Avestan yārǝ year, Greek ὥρα year, season, period of time, Old Church Slavonic jarŭ, Latin annus is from a PIE noun *h₂et-no-, which also yielded Gothic aþn year. Both *yeh₁-ro- and *h₂et-no- are based on verbal roots expressing movement, *h₁ey- and *h₂et- respectively, the Greek word for year, ἔτος, is cognate with Latin vetus old, from the PIE word *wetos- year, also preserved in this meaning in Sanskrit vat-sa- yearling and vat-sa-ras year. Derived from Latin annus are a number of English words, such as annual, annuity, anniversary, etc. per annum means each year, anno Domini means in the year of the Lord. No astronomical year has an number of days or lunar months. Financial and scientific calculations often use a 365-day calendar to simplify daily rates, in the Julian calendar, the average length of a year is 365.25 days. In a non-leap year, there are 365 days, in a year there are 366 days
5.
Precambrian
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The Precambrian is the earliest period of Earths history, set before the current Phanerozoic Eon. The Precambrian is a supereon that is subdivided into three eons of the time scale. It spans from the formation of Earth about 4.6 billion years ago to the beginning of the Cambrian Period, about 541 million years ago, the Precambrian accounts for 89% of geologic time. Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earths history, the Precambrian fossil record is poorer than that of the succeeding Phanerozoic, and fossils from that time are of limited biostratigraphic use. This is because many Precambrian rocks have been metamorphosed, obscuring their origins, while others have been destroyed by erosion. A stable crust was apparently in place by 4,412 Ma, the term Precambrian is recognized by the International Commission on Stratigraphy as a general term including the Archean and Proterozoic eons. It is still used by geologists and paleontologists for general discussions not requiring the more specific eon names and it was briefly called the Cryptozoic eon. A specific date for the origin of life has not been determined, carbon found in 3.8 billion year old rocks from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have found in Western Australia. Probable fossils 100 million years older have been found in the same area, there is a fairly solid record of bacterial life throughout the remainder of the Precambrian. The oldest fossil evidence from that era of such complex life comes from the Lantian formation of the Ediacarian period, a very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota, hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic era. By the middle of the following Cambrian period, a diverse fauna is recorded in the Burgess Shale. The explosion in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life, while land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas. Evidence of the details of plate motions and other activity in the Precambrian has been poorly preserved. It is generally believed that small proto-continents existed prior to 4280 Ma, the supercontinent, known as Rodinia, broke up around 750 Ma. A number of glacial periods have been identified going as far back as the Huronian epoch, one of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a Snowball Earth. The atmosphere of the early Earth is not well understood, most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and was lacking in free oxygen
6.
Cambrian
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The Cambrian Period was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago to the beginning of the Ordovician Period 485.4 mya and its subdivisions, and its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latinised form of Cymru, the Welsh name for Wales, as a result, our understanding of the Cambrian biology surpasses that of some later periods. The rapid diversification of lifeforms in the Cambrian, known as the Cambrian explosion, most of the continents were probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia, the seas were relatively warm, and polar ice was absent for much of the period. The United States Federal Geographic Data Committee uses a barred capital C ⟨Є⟩ character similar to the capital letter Ukrainian Ye ⟨Є⟩ to represent the Cambrian Period, the proper Unicode character is U+A792 Ꞓ LATIN CAPITAL LETTER C WITH BAR. Despite the long recognition of its distinction from younger Ordovician Period rocks and older Supereon Precambrian rocks, the base of the Cambrian lies atop a complex assemblage of trace fossils known as the Treptichnus pedum assemblage. Pedum in Namibia, Spain and Newfoundland, and possibly, in the western USA, the stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain. The Cambrian Period followed the Ediacaran Period and was followed by the Ordovician Period, the Cambrian is divided into four epochs and ten ages. Currently only two series and five stages are named and have a GSSP, because the international stratigraphic subdivision is not yet complete, many local subdivisions are still widely used. In some of these subdivisions the Cambrian is divided into three epochs with locally differing names – the Early Cambrian, Middle Cambrian and Furongian, rocks of these epochs are referred to as belonging to the Lower, Middle, or Upper Cambrian. Trilobite zones allow biostratigraphic correlation in the Cambrian, each of the local epochs is divided into several stages. The International Commission on Stratigraphy list the Cambrian period as beginning at 541 million years ago, the lower boundary of the Cambrian was originally held to represent the first appearance of complex life, represented by trilobites. The recognition of small shelly fossils before the first trilobites, and Ediacara biota substantially earlier and this formal designation allowed radiometric dates to be obtained from samples across the globe that corresponded to the base of the Cambrian. Early dates of 570 million years ago quickly gained favour, though the used to obtain this number are now considered to be unsuitable. A more precise date using modern radiometric dating yield a date of 541 ±0.3 million years ago, most continental land was clustered in the Southern Hemisphere at this time, but was drifting north. Large, high-velocity rotational movement of Gondwana appears to have occurred in the Early Cambrian, the sea levels fluctuated somewhat, suggesting there were ice ages, associated with pulses of expansion and contraction of a south polar ice cap. In Baltoscandia a Lower Cambrian transgression transformed large swathes of the Sub-Cambrian peneplain into a epicontinental sea, the Earth was generally cold during the early Cambrian, probably due to the ancient continent of Gondwana covering the South Pole and cutting off polar ocean currents
7.
Ordovician
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The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya. Lapworth recognized that the fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods. It received international sanction in 1960, when it was adopted as a period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event considerably increased the diversity of life, fish, the worlds first true vertebrates, continued to evolve, and those with jaws may have first appeared late in the period. Life had yet to diversify on land, about 100 times as many meteorites struck the Earth during the Ordovician compared with today. The Ordovician Period began with a major extinction called the Cambrian–Ordovician extinction event and it lasted for about 42 million years and ended with the Ordovician–Silurian extinction event, about 443.8 Mya which wiped out 60% of marine genera. The dates given are recent radiometric dates and vary slightly from those found in other sources and this second period of the Paleozoic era created abundant fossils that became major petroleum and gas reservoirs. The boundary chosen for the beginning of both the Ordovician Period and the Tremadocian stage is highly significant and it correlates well with the occurrence of widespread graptolite, conodont, and trilobite species. The base of the Tremadocian allows scientists to relate these species not only to each other and this makes it easier to place many more species in time relative to the beginning of the Ordovician Period. A number of terms have been used to subdivide the Ordovician Period. In 2008, the ICS erected an international system of subdivisions. There exist Baltoscandic, British, Siberian, North American, Australian, the Ordovician Period in Britain was traditionally broken into Early, Middle and Late epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, the Floian corresponds to the lower Arenig, the Arenig continues until the early Darriwilian, subsuming the Dapingian. The Llanvirn occupies the rest of the Darriwilian, and terminates with it at the base of the Late Ordovician. The Sandbian represents the first half of the Caradoc, the Caradoc ends in the mid-Katian, during the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole, the small continent Avalonia separated from Gondwana and began to move north towards Baltica and Laurentia, opening the Rheic Ocean between Gondwana and Avalonia
8.
Silurian
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The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago, to the beginning of the Devonian Period,419.2 Mya. As with other periods, the rock beds that define the periods start and end are well identified. The base of the Silurian is set at a major Ordovician-Silurian extinction event when 60% of marine species were wiped out, a significant evolutionary milestone during the Silurian was the diversification of jawed and bony fish. However, terrestrial life would not greatly diversify and affect the landscape until the Devonian, the Silurian system was first identified by British geologist Sir Roderick Impey Murchison, who was examining fossil-bearing sedimentary rock strata in south Wales in the early 1830s. He named the sequences for a Celtic tribe of Wales, the Silures, inspired by his friend Adam Sedgwick and this naming does not indicate any correlation between the occurrence of the Silurian rocks and the land inhabited by the Silures. As it was first identified, the Silurian series when traced farther afield quickly came to overlap Sedgwicks Cambrian sequence, however, charles Lapworth resolved the conflict by defining a new Ordovician system including the contested beds. An early alternative name for the Silurian was Gotlandian after the strata of the Baltic island of Gotland, the French geologist Joachim Barrande, building on Murchisons work, used the term Silurian in a more comprehensive sense than was justified by subsequent knowledge. He divided the Silurian rocks of Bohemia into eight stages and his interpretation was questioned in 1854 by Edward Forbes, and the later stages of Barrande, F, G and H, have since been shown to be Devonian. Despite these modifications in the groupings of the strata, it is recognized that Barrande established Bohemia as a classic ground for the study of the earliest fossils. The epoch is named for the town of Llandovery in Carmarthenshire, the Wenlock, which lasted from 433.4 ±1.5 to 427.4 ±2.8 mya, is subdivided into the Sheinwoodian and Homerian ages. It is named after Wenlock Edge in Shropshire, England, during the Wenlock, the oldest known tracheophytes of the genus Cooksonia, appear. The first terrestrial animals also appear in the Wenlock, represented by air-breathing millipedes from Scotland. The Ludlow, lasting from 427.4 ±1.5 to 423 ±2.8 mya, comprises the Gorstian stage, lasting until 425.6 million years ago, and it is named for the town of Ludlow in Shropshire, England. The Pridoli, lasting from 423 ±1.5 to 419.2 ±2.8 mya, is the final and it is named after one locality at the Homolka a Přídolí nature reserve near the Prague suburb Slivenec in the Czech Republic. Přídolí is the old name of a field area. The high sea levels of the Silurian and the flat land resulted in a number of island chains. The southern continents remained united during this period, the melting of icecaps and glaciers contributed to a rise in sea level, recognizable from the fact that Silurian sediments overlie eroded Ordovician sediments, forming an unconformity. The continents of Avalonia, Baltica, and Laurentia drifted together near the equator and this event is the Caledonian orogeny, a spate of mountain building that stretched from New York State through conjoined Europe and Greenland to Norway
9.
Devonian
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The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian,419.2 million years ago, to the beginning of the Carboniferous,358.9 Mya. It is named after Devon, England, where rocks from this period were first studied, the first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents, by the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established, Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fish. The first ray-finned and lobe-finned bony fish appeared, while the placodermi began dominating almost every aquatic environment. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their strong pectoral, in the oceans, primitive sharks became more numerous than in the Silurian and Late Ordovician. The first ammonites, species of molluscs, appeared, trilobites, the mollusk-like brachiopods and the great coral reefs, were still common. The Late Devonian extinction which started about 375 million years ago severely affected marine life, killing off all placodermi, and all trilobites, save for a few species of the order Proetida. The palaeogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, while the rock beds that define the start and end of the Devonian period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, the Devonian extends from the end of the Silurian 419.2 Mya, another common term is Age of the Fishes, referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian, Breconian and Farlovian stages, in the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common. The Devonian Period is formally broken into Early, Middle and Late subdivisions, the rocks corresponding to those epochs are referred to as belonging to the Lower, Middle and Upper parts of the Devonian System. Early Devonian The Early Devonian lasted from 419.2 ±2.8 to 393.3 ±2.5 and began with the Lochkovian stage, which lasted until the Pragian. It spanned from 410.8 ±2.8 to 407.6 ±2.5, and was followed by the Emsian, which lasted until the Middle Devonian began,393. 3±2.7 million years ago. Middle Devonian The Middle Devonian comprised two subdivisions, first the Eifelian, which gave way to the Givetian 387. 7±2.7 million years ago. Late Devonian Finally, the Late Devonian started with the Frasnian,382.7 ±2.8 to 372.2 ±2.5, during which the first forests took shape on land. The first tetrapods appeared in the record in the ensuing Famennian subdivision. This lasted until the end of the Devonian,358. 9±2.5 million years ago, the Devonian was a relatively warm period, and probably lacked any glaciers
10.
Carboniferous
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The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period,298.9 Mya. The name Carboniferous means coal-bearing and derives from the Latin words carbō and ferō, and was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the system names to be employed. The Carboniferous is often treated in North America as two periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial life was established by the Carboniferous period. Amphibians were the dominant land vertebrates, of one branch would eventually evolve into amniotes. Arthropods were also common, and many were much larger than those of today. Vast swaths of forest covered the land, which would eventually be laid down, the atmospheric content of oxygen also reached their highest levels in geological history during the period, 35% compared with 21% today, allowing terrestrial invertebrates to evolve to great size. A major marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred in the middle of the period, the later half of the period experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea. In the United States the Carboniferous is usually broken into Mississippian and Pennsylvanian subperiods, the Silesian is roughly contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. In Britain the Dinantian is traditionally known as the Carboniferous Limestone, the Namurian as the Millstone Grit, and the Westphalian as the Coal Measures and Pennant Sandstone. There was also a drop in south polar temperatures, southern Gondwanaland was glaciated throughout the period and these conditions apparently had little effect in the deep tropics, where lush swamps, later to become coal, flourished to within 30 degrees of the northernmost glaciers. Mid-Carboniferous, a drop in sea level precipitated a major extinction, one that hit crinoids. This sea level drop and the unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 323 million years ago, at the onset of the Permo-Carboniferous Glaciation, the Carboniferous was a time of active mountain-building, as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe along the present line of eastern North America, in the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China, the Late Carboniferous Pangaea was shaped like an O. There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, which was inside the O in the Carboniferous Pangaea, other minor oceans were shrinking and eventually closed - Rheic Ocean, the small, shallow Ural Ocean and Proto-Tethys Ocean
11.
Permian
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The Permian is a geologic period and system which spans 46.7 million years from the end of the Carboniferous Period 298.9 million years ago, to the beginning of the Triassic Period 252.2 Mya. It is the last period of the Paleozoic Era, the following Triassic Period belongs to the Mesozoic Era, the concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian witnessed the diversification of the early amniotes into the groups of the mammals, turtles, lepidosaurs. The world at the time was dominated by two known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior, amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. The Permian ended with the Permian–Triassic extinction event, the largest mass extinction in Earths history, in which nearly 90% of marine species and it would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian-Triassic extinction event was protracted, on land, the term Permian was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil, the region now lies in the Perm Krai of Russia. This could have in part caused the extinctions of marine species at the end of the period by severely reducing shallow coastal areas preferred by many marine organisms. During the Permian, all the Earths major landmasses were collected into a supercontinent known as Pangaea. The Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, a new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic Era. Large continental landmass interiors experience climates with extreme variations of heat and cold, deserts seem to have been widespread on Pangaea. Such dry conditions favored gymnosperms, plants with seeds enclosed in a cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees appeared in the Permian, the climate in the Permian was quite varied. At the start of the Permian, the Earth was still in an Ice Age, glaciers receded around the mid-Permian period as the climate gradually warmed, drying the continents interiors. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles, Permian marine deposits are rich in fossil mollusks, echinoderms, and brachiopods. By the close of the Permian, trilobites and a host of other groups became extinct. Terrestrial life in the Permian included diverse plants, fungi, arthropods, the period saw a massive desert covering the interior of Pangaea
12.
Triassic
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The Triassic is a geologic period and system which spans 50.9 million years from the end of the Permian Period 252.17 million years ago, to the beginning of the Jurassic Period 201.3 Mya. The Triassic is the first period of the Mesozoic Era, both the start and end of the period are marked by major extinction events. Therapsids and archosaurs were the terrestrial vertebrates during this time. A specialized subgroup of archosaurs, called dinosaurs, first appeared in the Late Triassic, the vast supercontinent of Pangaea existed until the mid-Triassic, after which it began to gradually rift into two separate landmasses, Laurasia to the north and Gondwana to the south. The global climate during the Triassic was mostly hot and dry, however, the climate shifted and became more humid as Pangaea began to drift apart. The end of the period was marked by yet another mass extinction, the Triassic-Jurassic extinction event. The Triassic is usually separated into Early, Middle, and Late Triassic Epochs, from the east, along the equator, the Tethys sea penetrated Pangaea, causing the Paleo-Tethys Ocean to be closed. Later in the mid-Triassic a similar sea penetrated along the equator from the west, the remaining shores were surrounded by the world-ocean known as Panthalassa. All the deep-ocean sediments laid down during the Triassic have disappeared through subduction of oceanic plates, thus, the supercontinent Pangaea was rifting during the Triassic—especially late in that period—but had not yet separated. In North America, for example, marine deposits are limited to a few exposures in the west, thus Triassic stratigraphy is mostly based on organisms that lived in lagoons and hypersaline environments, such as Estheria crustaceans. At the beginning of the Mesozoic Era, Africa was joined with Earths other continents in Pangaea, Africa shared the supercontinents relatively uniform fauna which was dominated by theropods, prosauropods and primitive ornithischians by the close of the Triassic period. Late Triassic fossils are found throughout Africa, but are common in the south than north. The time boundary separating the Permian and Triassic marks the advent of an event with global impact. At Paleorrota geopark, located in Rio Grande do Sul, Brazil, in these formations, one of the earliest dinosaurs, Staurikosaurus, as well as the mammal ancestors Brasilitherium and Brasilodon have been discovered. The Triassic continental interior climate was hot and dry, so that typical deposits are red bed sandstones and evaporites. Pangaeas large size limited the effect of the global ocean, its continental climate was highly seasonal, with very hot summers. The strong contrast between the Pangea supercontinent and the global ocean triggered intense cross-equatorial monsoons, the best studied of such episodes of humid climate, and probably the most intense and widespread, was the Carnian Pluvial Event. On land, the vascular plants included the lycophytes, the dominant cycadophytes, ginkgophyta, ferns, horsetails
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Jurassic
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The Jurassic is a geologic period and system that spans 56.3 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles, the start of the period is marked by the major Triassic–Jurassic extinction event. The Jurassic is named after the Jura Mountains within the European Alps, by the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses, Laurasia to the north and Gondwana to the south. This created more coastlines and shifted the continental climate from dry to humid, on land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds also appeared during the Jurassic, having evolved from a branch of theropod dinosaurs, other major events include the appearance of the earliest lizards, and the evolution of therian mammals, including primitive placentals. Crocodilians made the transition from a terrestrial to a mode of life. The oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, the chronostratigraphic term Jurassic is directly linked to the Jura Mountains. The name Jura is derived from the Celtic root jor, which was Latinised into juria, the Jurassic period is divided into the Early Jurassic, Middle, and Late Jurassic epochs. The Jurassic System, in stratigraphy, is divided into the Lower Jurassic, Middle, the separation of the term Jurassic into three sections goes back to Leopold von Buch. The Jurassic North Atlantic Ocean was relatively narrow, while the South Atlantic did not open until the following Cretaceous period, the Tethys Sea closed, and the Neotethys basin appeared. Climates were warm, with no evidence of glaciation, as in the Triassic, there was apparently no land over either pole, and no extensive ice caps existed. In contrast, the North American Jurassic record is the poorest of the Mesozoic, the Jurassic was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate. Carbonate hardgrounds were thus very common, along with calcitic ooids, calcitic cements, the first of several massive batholiths were emplaced in the northern American cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny. Important Jurassic exposures are found in Russia, India, South America, Japan, Australasia. As the Jurassic proceeded, larger and more groups of dinosaurs like sauropods and ornithopods proliferated in Africa. Middle Jurassic strata are well represented nor well studied in Africa. Late Jurassic strata are also poorly represented apart from the spectacular Tendaguru fauna in Tanzania, the Late Jurassic life of Tendaguru is very similar to that found in western North Americas Morrison Formation. During the Jurassic period, the primary living in the sea were fish
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Cretaceous
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The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 Mya. It is the last period of the Mesozoic Era, the Cretaceous Period is usually abbreviated K, for its German translation Kreide. The Cretaceous was a period with a warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, during this time, new groups of mammals and birds, as well as flowering plants, appeared. The Cretaceous ended with a mass extinction, the Cretaceous–Paleogene extinction event, in which many groups, including non-avian dinosaurs, pterosaurs. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary, the name Cretaceous was derived from Latin creta, meaning chalk. The Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series, in older literature the Cretaceous is sometimes divided into three series, Neocomian, Gallic and Senonian. A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide, in many parts of the world, alternative local subdivisions are still in use. As with other geologic periods, the rock beds of the Cretaceous are well identified. No great extinction or burst of diversity separates the Cretaceous from the Jurassic and this layer has been dated at 66.043 Ma. A140 Ma age for the Jurassic-Cretaceous boundary instead of the usually accepted 145 Ma was proposed in 2014 based on a study of Vaca Muerta Formation in Neuquén Basin. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a first step toward formally changing the age in the International Union of Geological Sciences, due to the high sea level there was extensive space for such sedimentation. Because of the young age and great thickness of the system. Chalk is a type characteristic for the Cretaceous. It consists of coccoliths, microscopically small calcite skeletons of coccolithophores, the group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea. Chalk is not easily consolidated and the Chalk Group still consists of sediments in many places. The group also has other limestones and arenites, among the fossils it contains are sea urchins, belemnites, ammonites and sea reptiles such as Mosasaurus. In southern Europe, the Cretaceous is usually a marine system consisting of competent limestone beds or incompetent marls
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Paleogene
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The Paleogene is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago to the beginning of the Neogene Period 23.03 Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon and this period consists of the Paleocene, Eocene and Oligocene epochs. The terms Paleogene System and lower Tertiary System are applied to the rocks deposited during the Paleogene Period. By dividing the Tertiary Period into two periods instead of directly into five epochs, the periods are more comparable to the duration of periods of the preceding Mesozoic and Paleozoic Eras. The trend was caused by the formation of the Antarctic Circumpolar Current. During the Paleogene, the continued to drift closer to their current positions. India was in the process of colliding with Asia, subsequently forming the Himalayas, the Atlantic Ocean continued to widen by a few centimeters each year. Africa was moving north to meet with Europe and form the Mediterranean, inland seas retreated from North America early in the period. Australia had also separated from Antarctica and was drifting towards Southeast Asia, mammals began a rapid diversification during this period. Some of these mammals would evolve into forms that would dominate the land, while others would become capable of living in marine, specialized terrestrial. Those that took to the oceans became modern cetaceans, while those that took to the trees became primates, the group to which humans belong. Birds, which were well established by the end of the Cretaceous. In comparison to birds and mammals, most other branches of life remained unchanged during this period. As the Earth cooled, tropical plants became less numerous and were now restricted to equatorial regions, deciduous plants, which could survive through the seasonal climates the world was now experiencing, became more common. The Paleogene is notable in the context of offshore oil drilling, and especially in Gulf of Mexico oil exploration and these rock formations represent the current cutting edge of deep-water oil discovery. Lower Tertiary explorations to date include, Kaskida Oil Field Tiber Oil Field Jack 2 Paleogene Microfossils, 180+ images of Foraminifera
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Neogene
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The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene, some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. During this period, mammals and birds continued to evolve into modern forms. Early hominids, the ancestors of humans, appeared in Africa near the end of the period, some continental movement took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the ocean currents from the Pacific to the Atlantic ocean. The global climate cooled considerably over the course of the Neogene, the terms Neogene System and upper Tertiary System describe the rocks deposited during the Neogene Period. The continents in the Neogene were very close to their current positions, the Isthmus of Panama formed, connecting North and South America. The Indian subcontinent continued to collide with Asia, forming the Himalayas, sea levels fell, creating land bridges between Africa and Eurasia and between Eurasia and North America. The global climate became seasonal and continued an overall drying and cooling trend which began at the start of the Paleogene. The ice caps on both poles began to grow and thicken, and by the end of the period the first of a series of glaciations of the current Ice Age began, marine and continental flora and fauna have a modern appearance. The reptile group Choristodera became extinct in the part of the period. Mammals and birds continued to be the dominant terrestrial vertebrates, the first hominids, the ancestors of humans, appeared in Africa and spread into Eurasia. In response to the cooler, seasonal climate, tropical plant species gave way to deciduous ones, grasses therefore greatly diversified, and herbivorous mammals evolved alongside it, creating the many grazing animals of today such as horses, antelope, and bison. The Neogene traditionally ended at the end of the Pliocene Epoch, just before the definition of the beginning of the Quaternary Period. However, there was a movement amongst geologists to also include ongoing geological time in the Neogene, by dividing the Cenozoic Era into three periods instead of seven epochs, the periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic eras. The International Commission on Stratigraphy once proposed that the Quaternary be considered a sub-era of the Neogene, with a date of 2.58 Ma. In the 2004 proposal of the ICS, the Neogene would have consisted of the Miocene and Pliocene epochs, thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya. Digital Atlas of Neogene Life for the Southeastern United States — by San Jose State University via Web Archive
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Homo sapiens
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Homo sapiens is the binomial nomenclature for the only extant human species. Homo is the genus, which also includes Neanderthals and many other extinct species of hominid. Modern humans are the subspecies Homo sapiens sapiens, which differentiates them from what has been argued to be their direct ancestor, the binomial name Homo sapiens was coined by Carl Linnaeus. The Latin noun homō means man, human being, subspecies of H. sapiens include Homo sapiens idaltu and the only extant subspecies, Homo sapiens sapiens. Some sources show Neanderthals as a subspecies, similarly, the discovered specimens of the Homo rhodesiensis species have been classified by some as a subspecies, but these last two subspecies classifications are not widely accepted by scientists. Traditionally, there are two competing views in paleoanthropology about the origin of H. sapiens, the recent African origin, since 2010, genetic research has led to the emergence of an intermediate position, characterised by mostly recent African origin plus limited admixture with archaic humans. The recent African origin of humans is the mainstream model that describes the origin. The theory is called the Out-of-Africa model in the press, and academically the recent single-origin hypothesis, Replacement Hypothesis. The hypothesis that humans have a single origin was published in Charles Darwins Descent of Man, the concept was speculative until the 1980s, when it was corroborated by a study of present-day mitochondrial DNA, combined with evidence based on physical anthropology of archaic specimens. The recent single origin of humans in East Africa is the near-consensus position held within the scientific community. However, recent sequencing of the full Neanderthal genome suggests Neanderthals, the authors of the study suggest that their findings are consistent with Neanderthal admixture of up to 4% in some populations. But the study suggests that there may be other reasons why humans. That study however does not explain why only a fraction of humans have Neanderthal DNA. The multiregional origin model provides an explanation for the pattern of evolution proposed by Milford H. Wolpoff in 1988. Scientific study of evolution is concerned, primarily, with the development of the genus Homo. Modern humans are defined as the Homo sapiens species, of which the extant subspecies is known as Homo sapiens sapiens. Homo sapiens idaltu, the known subspecies, is now extinct. Similarly, the specimens of the Homo rhodesiensis species have been classified by some as a subspecies
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Common chimpanzee
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The common chimpanzee, also known as the robust chimpanzee, is a species of great ape. Evidence from fossils and DNA sequencing shows both species of chimpanzees are the group to the modern human lineage. The common chimpanzee is covered in black hair, but has a bare face, fingers, toes, palms of the hands. It is considered more robust than the bonobo, weighing between 40 and 65 kg and measuring about 63 to 94 cm and its gestation period is eight months. The common chimpanzee lives in groups which range in size from 15 to 150 members, although individuals travel, the species lives in a male-dominated, strict hierarchy, which means disputes can generally be settled without the need for violence. Nearly all chimpanzee populations have been recorded using tools, modifying sticks, rocks, grass, and leaves and using them for acquiring honey, termites, ants, nuts, the species has also been found creating sharpened sticks to spear Senegal bushbabies out of small holes in trees. The common chimpanzee is listed on the IUCN Red List as an endangered species, between 170,000 and 300,000 individuals are estimated across its range in the forests and savannahs of West and Central Africa. The biggest threats to the common chimpanzee are habitat loss, poaching, the common chimpanzee was named Simia troglodytes by Johann Friedrich Blumenbach in 1776, Lorenz Oken moved it to the new genus Pan in 1816. The species name troglodytes is a reference to the Troglodytae, an African people described by Greco-Roman geographers, Blumenbach first used it in his De generis humani varietate nativa liber in 1776. The English name chimpanzee is first recorded in 1738 and it is derived from a Tshiluba language term kivili-chimpenze, with a meaning of mockman or possibly just ape. The colloquialism chimp was most likely coined some time in the late 1870s, despite a large number of Homo fossil finds, chimpanzee fossils were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the human fossil sites in East Africa. However, chimpanzee fossils have now been reported from Kenya and this would indicate that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene. DNA evidence suggests the bonobo and common chimpanzee species separated from other less than one million years ago. The chimpanzee line split from the last common ancestor of the line around six million years ago. Because no species other than Homo sapiens has survived from the line of that branching. The lineage of humans and chimpanzees diverged from that of the gorilla about seven years ago. The adult male common chimpanzee weighs between 40 and 60 kg, the female weighs 32 to 47 kg, however, large wild males can weigh up to 70 kg and males in captivity, such as Travis the Chimp, have reached 91 kg
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Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
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Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
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Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
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Mammal
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Mammals are any vertebrates within the class Mammalia, a clade of endothermic amniotes distinguished from reptiles by the possession of a neocortex, hair, three middle ear bones and mammary glands. All female mammals nurse their young with milk, secreted from the mammary glands, Mammals include the largest animals on the planet, the great whales. The basic body type is a quadruped, but some mammals are adapted for life at sea, in the air, in trees. The largest group of mammals, the placentals, have a placenta, Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale. With the exception of the five species of monotreme, all modern mammals give birth to live young, most mammals, including the six most species-rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha, the next three biggest orders, depending on the biological classification scheme used, are the Primates, the Cetartiodactyla, and the Carnivora. Living mammals are divided into the Yinotheria and Theriiformes There are around 5450 species of mammal, in some classifications, extant mammals are divided into two subclasses, the Prototheria, that is, the order Monotremata, and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the group of the Metatheria, and include all living metatherians as well as many extinct ones. Much of the changes reflect the advances of cladistic analysis and molecular genetics, findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora. The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade, the early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the line that led to todays reptiles. Some mammals are intelligent, with some possessing large brains, self-awareness, Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals, singing, and echolocation. Mammals can organize themselves into fission-fusion societies, harems, and hierarchies, most mammals are polygynous, but some can be monogamous or polyandrous. They provided, and continue to provide, power for transport and agriculture, as well as commodities such as meat, dairy products, wool. Mammals are hunted or raced for sport, and are used as model organisms in science, Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is accepted, McKenna & Bell and Wilson & Reader provide useful recent compendiums. Though field work gradually made Simpsons classification outdated, it remains the closest thing to a classification of mammals
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Primate
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A primate is a mammal of the order Primates. In taxonomy, primates include two distinct lineages, strepsirrhines and haplorhines, Primates arose from ancestors that lived in the trees of tropical forests, many primate characteristics represent adaptations to life in this challenging three-dimensional environment. Most primate species remain at least partly arboreal, with the exception of humans, who inhabit every continent except for Antarctica, most primates live in tropical or subtropical regions of the Americas, Africa and Asia. Based on fossil evidence, the earliest known true primates, represented by the genus Teilhardina, an early close primate relative known from abundant remains is the Late Paleocene Plesiadapis, c. Molecular clock studies suggest that the branch may be even older. The order Primates was traditionally divided into two groupings, prosimians and anthropoids. Prosimians have characteristics more like those of the earliest primates, and include the lemurs of Madagascar, lorisoids, simians include monkeys, apes and hominins. Simians are divided into two groups, catarrhine monkeys and apes of Africa and Southeast Asia and platyrrhine or New World monkeys of South, catarrhines consist of Old World monkeys, gibbons and great apes, New World monkeys include the capuchin, howler and squirrel monkeys. Humans are the only extant catarrhines to have spread successfully outside of Africa, South Asia, New primate species are still being discovered. More than 25 species were described in the decade of the 2000s. Considered generalist mammals, primates exhibit a range of characteristics. Some primates are primarily terrestrial rather than arboreal, but all species possess adaptations for climbing trees, locomotion techniques used include leaping from tree to tree, walking on two or four limbs, knuckle-walking, and swinging between branches of trees. Primates are characterized by large brains relative to other mammals, as well as a reliance on stereoscopic vision at the expense of smell. These features are developed in monkeys and apes and noticeably less so in lorises. Three-color vision has developed in some primates, most also have opposable thumbs and some have prehensile tails. Many species are dimorphic, differences include body mass, canine tooth size. Primates have slower rates of development than other similarly sized mammals and reach maturity later, depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members. The relationships among the different groups of primates were not clearly understood until relatively recently, for example, ape has been used either as an alternative for monkey or for any tailless, relatively human-like primate
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Haplorhini
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Haplorrhini is a clade containing the tarsiers and the simians. The name is also spelt Haplorrhini, the simians include catarrhines, and the platyrrhines. The extinct omomyids, which are considered to be the most basal haplorhines, are believed to be closely related to the tarsiers than to other haplorhines. Haplorhines share a number of derived features that distinguish them from the strepsirrhine wet-nosed primates, the haplorhine upper lip, which has replaced the ancestral rhinarium found in strepsirrhines, is not directly connected to their nose or gum, allowing a large range of facial expressions. Their brain-to-body mass ratio is greater than the strepsirrhines. Haplorhines have a plate, unlike the postorbital bar found in strepsirrhines. All anthropoids have a uterus, tarsiers have a bicornate uterus like the strepsirrhines. Most species typically have single births, although twins and triplets are common for marmosets, despite similar gestation periods, haplorhine newborns are relatively much larger than strepsirrhine newborns, but have a longer dependence period on their mother. This difference in size and dependence is credited to the complexity of their behavior. The taxonomic name Haplorhini derives from the Ancient Greek haploûs and rhinos and it refers to the lack of a rhinarium or wet nose, which is found in many mammals, including strepsirrhine primates. Haplorhini and its sister clade, Strepsirrhini, diverged about 65 million years ago, the fossil Archicebus may be similar to the most recent common ancestor at this time. The other major clade within Haplorhini, the simians, is divided into two parvorders, Platyrrhini and Catarrhini, the New World monkeys split from catarrhines about 40 mya, while the apes diverged from Old World monkeys about 25 mya. The available fossil evidence indicates both the hominoid and cercopithecoid clades originated in Africa. The following is the listing of the living families, and their placement in the Order Primates, ORDER PRIMATES Suborder Strepsirrhini, lemurs, lorises
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Simian
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The simians are the monkeys, cladistically including the apes, the New World monkeys or platyrrhines, and the catarrhine clade consisting of the Old World monkeys and apes. The simian line and the line diverged about 60 million years ago. Forty million years ago, simians from Africa colonized South America, the remaining simians split 25 million years ago into apes and Old World monkeys. Under modern classification, the tarsiers and simians are grouped under the suborder Haplorhini while the strepsirrhines are placed in suborder Strepsirrhini, in anthropoidea, evidences indicate that the Old and the New World primates went through parallel evolution. Primatology, paleoanthropology, and other related fields are split on their usage of the synonymous infraorder names, Simiiformes and Anthropoidea. According to Robert Hoffstetter, the term Simiiformes has priority over Anthropoidea because of the taxonomic term Simii by van der Hoeven, from which it is constructed, dates to 1833. In contrast, Anthropoidea by Mivart dates to 1864, while Simiiformes by Haeckel dates to 1866, Hoffstetter also argued that Simiiformes is also constructed like a proper infraorder name, whereas Anthropoidea ends in -oidea, which is reserved for superfamilies. He also noted that Anthropoidea is too easily confused with anthropoïdes, the simians are split into three distinct groups. The New World monkeys in parvorder Platyrrhini split from the rest of the line about 40 mya. This group split about 25 mya between the Old World monkeys and the apes
26.
John Edward Gray
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John Edward Gray, FRS was a British zoologist. He was the brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray. Gray was Keeper of Zoology at the British Museum in London from 1840 until Christmas 1874 and he published several catalogues of the museum collections that included comprehensive discussions of animal groups as well as descriptions of new species. He improved the zoological collections to make them amongst the best in the world, Gray was born in Walsall, but his family soon moved to London, where Gray studied medicine. He assisted his father in writing The Natural Arrangement of British Plants, after being blackballed by the Linnean Society he turned his interest from botany to zoology. He began his career by volunteering to collect insects for the British Museum at age 15. He officially joined the Zoological Department in 1824 to help John George Children catalog the reptile collection, in 1840 he took over from Children as Keeper of Zoology, which he continued for 35 years, publishing well over 1000 papers. He named many species, genera, subfamilies, and families. During this period he collaborated with Benjamin Waterhouse Hawkins, the natural history artist. Knowsley Park, near Liverpool, had been founded by Edward Stanley, Gray married Maria Emma Smith in 1826. She helped him with his work, especially with her drawings. In 1833, he was a founder of what became the Royal Entomological Society of London, during his fifty years employed at the British Museum Gray wrote nearly 500 papers, including many descriptions of species new to science. He was also active in malacology, the study of molluscs, on his death he was buried at St Marys Church, Lewisham. 1821, On the natural arrangement of Vertebrose Animals,1824, A revision of the family Equidae. 1824, On the natural arrangement of the pulmonobranchous Mollusca, annals of Philosophy, new series 8, 107–109. 1825, A list and description of species of shells not taken notice of by Lamarck. 1825, An outline of an attempt at the disposition of the Mammalia into tribes and families with a list of the genera apparently appertaining to each tribe, narrative of a Survey of the Intertropical and Western Coasts of Australia. Performed between the years 1818 and 1822, with an Appendix, containing various subjects relating to hydrography and natural history
27.
Type species
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A similar concept is used for suprageneric groups called a type genus. In botanical nomenclature, these terms have no standing under the code of nomenclature. In botany, the type of a name is a specimen which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name, names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. In bacteriology, a species is assigned for each genus. Every named genus or subgenus in zoology, whether or not currently recognized as valid, is associated with a type species. In practice, however, there is a backlog of untypified names defined in older publications when it was not required to specify a type, a type species is both a concept and a practical system that is used in the classification and nomenclature of animals. The type species represents the species and thus definition for a particular genus name. In the Glossary, type species is defined as The nominal species that is the type of a nominal genus or subgenus. The type species permanently attaches a formal name to a genus by providing just one species within that genus to which the name is permanently linked. The species name in turn is fixed, in theory, to a type specimen, for example, the type species for the land snail genus Monacha is Monacha cartusiana. That genus is placed within the family Hygromiidae. The type genus for that family is the genus Hygromia, the concept of the type species in zoology was introduced by Pierre André Latreille. The International Code of Zoological Nomenclature states that the name of the type species should always be cited. It gives an example in Article 67.1, Astacus marinus Fabricius,1775 was later designated as the type species of the genus Homarus, thus giving it the name Homarus marinus. However, the species of Homarus should always be cited using its original name. 3, the type of the genus name Elodes is quoted as the type of the species name Hypericum aegypticum, Glossary of scientific naming Genetypes – genetic sequence data from type specimens. Holotype Paratype Principle of Typification Type Type genus
28.
Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
29.
Genus
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A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of classification, genus comes above species. In binomial nomenclature, the name forms the first part of the binomial species name for each species within the genus. Felis catus and Felis silvestris are two species within the genus Felis, Felis is a genus within the family Felidae. The composition of a genus is determined by a taxonomist, the standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. Moreover, genera should be composed of units of the same kind as other genera. The term comes from the Latin genus, a noun form cognate with gignere, linnaeus popularized its use in his 1753 Species Plantarum, but the French botanist Joseph Pitton de Tournefort is considered the founder of the modern concept of genera. The scientific name of a genus may be called the name or generic epithet. It plays a role in binomial nomenclature, the system of naming organisms. The rules for the names of organisms are laid down in the Nomenclature Codes. The standard way of scientifically describing species and other lower-ranked taxa is by binomial nomenclature, the generic name forms its first half. For example, the gray wolfs binomial name is Canis lupus, with Canis being the name shared by the wolfs close relatives. The specific name is written in lower-case and may be followed by names in zoology or a variety of infraspecific names in botany. Especially with these names, when the generic name is known from context. Because animals are typically only grouped within subspecies, it is written as a trinomen with a third name. Dog breeds, meanwhile, are not scientifically distinguished, there are several divisions of plant species and therefore their infraspecific names generally include contractions explaining the relation. For example, the genus Hibiscus includes hundreds of other species apart from the Rose of Sharon or common garden hibiscus, Rose of Sharon doesnt have subspecies but has cultivars that carry desired traits, such as the bright white H. syriaca Diana. Hawaiian hibiscus, meanwhile, includes several separate species, since not all botanists agree on the divisions or names between species, it is common to specify the source of the name using author abbreviations
30.
Chimpanzee
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Chimpanzees are one of the two species of the genus Pan, the other being the bonobo. Together with gorillas, they are the only exclusively African species of ape that are currently extant. Native to sub-Saharan Africa, both chimpanzees and bonobos are found in the Congo jungle. In addition, P. troglodytes is divided into four subspecies, based on genome sequencing, the two extant Pan species diverged around one million years ago. The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful and their hair is typically black or brown. Males and females differ in size and appearance, both chimps and bonobos are some of the most social great apes, with social bonds occurring among individuals in large communities. Fruit is the most important component of a diet, however, they will also eat vegetation, bark, honey, insects. They can live over 30 years in both the wild and captivity, Chimpanzees and bonobos are equally humanitys closest living relatives. As such, they are among the largest-brained, and most intelligent of primates, they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and they have both been extensively studied for their learning abilities. There may even be distinctive cultures within populations, field studies of Pan troglodytes were pioneered by primatologist Jane Goodall. Both Pan species are considered to be endangered as human activities have caused declines in the populations. Threats to wild populations include poaching, habitat destruction. Several conservation and rehabilitation organisations are dedicated to the survival of Pan species in the wild, the first use of the name chimpanze is recorded in The London Magazine in 1738, glossed as meaning mockman in a language of the Angolans. The spelling chimpanzee is found in a 1758 supplement to Chambers Cyclopædia, the colloquialism chimp was most likely coined some time in the late 1870s. The common chimpanzee was named Simia troglodytes by Johann Friedrich Blumenbach in 1776, the species name troglodytes is a reference to the Troglodytae, an African people described by Greco-Roman geographers. Blumenbach first used it in his De generis humani varietate nativa liber in 1776, the genus name Pan was first introduced by Lorenz Oken in 1816. An alternative Theranthropus was suggested by Brookes 1828 and Chimpansee by Voigt 1831, troglodytes was not available, as it had been given as the name of a genus of wren in 1809. The International Commission on Zoological Nomenclature adopted Pan as the official name of the genus in 1895
31.
Australopithecine
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Australopithecines are generally all species in the related Australopithecus and Paranthropus genera, and it typically includes Kenyanthropus, Ardipithecus, and Praeanthropus. All these related species are now sometimes collectively classified as a subtribe of the Hominini tribe called Australopithecina and they are the extinct, close relatives of humans and, with the extant genus Homo, comprise the human clade. Members of the clade, i. e. the Hominini after the split from the chimpanzees, are now called homonina. The terms australopithecine, et al. come from a classification as members of a distinct subfamily. Members of Australopithecus are sometimes referred to as the gracile australopithecines, humans may have descended from australopithecine ancestors and the genus Ardipithecus is a possible ancestor of the australopithecines. Phylogeny of subtribe Australopithecina according to Briggs & Crowther 2008, p.124 and they have a high brachial index when compared to other hominins, and they exhibit greater sexual dimorphism than members of Homo or Pan but less so than Gorilla or Pongo. It is thought that they averaged heights of 1. 2–1.5 metres, the brain size may have been 350 cc to 600 cc. Most scientists maintain that one of the species evolved into the Homo genus in Africa around two million years ago. Nearly every possible species has been suggested as a likely candidate, presently, it appears that A. garhi has the potential to occupy this coveted place in paleoanthropology, but the lack of fossil evidence is a serious problem. Another problem presents itself in the fact that it has very difficult to assess which hominid represents the first member of the genus Homo. Without knowing this, it is not possible to determine which species of australopithecine may have been ancestral to Homo, marc Verhaegen has argued that an australopithecine species could have also been ancestral to the Pan genus. A minority held viewpoint among palaeoanthropologists is that australopithecines moved outside of Africa, a notable proponent of this theory is Jens Lorenz Franzen, formerly Head of Paleoanthropology at the Research Institute Senckenberg. In 1957, an Early Pleistocene Chinese fossil tooth of unknown province was described as resembling P. robustus, three fossilized molars from Jianshi, China were later identified as belonging to an Australopithecus species. However further examination questioned this interpretation, Zhang argued the Jianshi teeth, but, Wolpoff notes that in China persistent claims of australopithecine or australopithecine-like remains continue. Dawn of Humanity Human taxonomy Informative lecture on Australopithecines
32.
Australopithecus
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Australopithecus is an extinct genus of hominins. During that time, a number of australopithecine species emerged, including Australopithecus afarensis, A. africanus, A. anamensis, A. bahrelghazali, A. deyiremeda, A. garhi, and A. sediba. For some hominid species of time, such as A. robustus and A. boisei. If so, they would be considered robust australopiths, while the others would be gracile australopiths, however, if these species do constitute their own genus, they may be given their own name, Paranthropus. Australopithecus species played a significant part in human evolution, the genus Homo being derived from Australopithecus at some time after three years ago. Among other things, they were the first hominids to show the presence of a gene that causes increased length and ability of neurons in the brain, the duplicated SRGAP2 gene. One of the species eventually became the Homo genus in Africa around two million years ago, and eventually modern humans, H. sapiens sapiens. Gracile australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa around 3.5 million years ago, the earliest evidence of fundamentally bipedal hominids can be observed at the site of Laetoli in Tanzania. This site contains hominid footprints that are similar to those of modern humans and have been dated to as old as 3.6 million years. The footprints have generally classified as australopith because that is the only form of prehuman known to have existed in that region at that time. Australopithecus anamensis, A. afarensis, and A. africanus are among the most famous of the extinct hominins, a. africanus was once considered to be ancestral to the genus Homo. However, fossils assigned to the genus Homo have been found that are older than A. africanus, thus, the genus Homo either split off from the genus Australopithecus at an earlier date, or both developed from a yet possibly unknown common ancestor independently. According to the Chimpanzee Genome Project, the human and chimpanzee lineages diverged from a common ancestor about five to six years ago. Sahelanthropus tchadensis, commonly called Toumai, is seven million years old. One theory suggests that the human and chimpanzee lineages diverged somewhat at first, the brains of most species of Australopithecus were roughly 35% of the size of a modern human brain. Most species of Australopithecus were diminutive and gracile, usually standing 1.2 to 1.4 m tall, in several variations is a considerable degree of sexual dimorphism, males being larger than females. According to one scholar, A. Furthermore, thermoregulatory models suggest that Australopithecus species were fully covered, more like chimpanzees and bonobos. Modern humans do not appear to display the same degree of sexual dimorphism as Australopithecus did, in modern populations, males are on average a mere 15% larger than females, while in Australopithecus, males could be up to 50% larger than females
33.
Kenyanthropus
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Kenyanthropus platyops is a 3.5 to 3. 2-million-year-old hominin fossil discovered in Lake Turkana, Kenya in 1999 by Justus Erus, who was part of Meave Leakeys team. The species name “platyops” is derived from two Greek words, platus, which means flat, and opsis, which means face and this indicated that species were much more diverse in the distant past than previously thought. Even with the findings of a skull, their diet is still unknown at this time. Also, no evidence of culture or anything that would lead to its behavioral adaptations or lifestyle has been discovered at this time. Several aspects of the environment in which it may have lived have been proposed and it is believed that they lived in a “mosaic” environment, which had both grassland and some forested areas. In 1999, Meave Leakey led an expedition in Kenya to dig for fossils, the first expedition was in 1998 in which the paratype, KNM-WT38350 was discovered. They began to dig at a site that had yielded many other prominent hominin fossil specimens, Lake Turkana, a member of the team, Justus Erus, discovered a skull in the Nachukui Formation at Lomekwi, an area of specific geology right next to the lake. KNM-WT40000 and the bones were collected from a dark mudstone. The mudstone was located in between the Lokochot Tuff and the Tulu Bor Tuff in the Kataboi Member, beneath the Lokochot Tuff were the Moiti Tuff and the Topernawi Tuff. The KNM-WT40000 specimen was dated at 3.5 million years, directly beneath the bed was the KNM-WT38341 specimen, which was dated at 3.53 million years. Other specimens from various localities that were found above the b-Tulu Bor Tuff were dated at around 3.3 million years, the location of the mudstone was near a shallow lake, suggesting that the hominins lived near rivers or lakes. KNM-WT40000 is the holotype, the specimen of which the description, the fossils of Kenyanthropus platyops indicate that hominins were more taxonomically diverse during the middle Pliocene. The discovery of this fossil also dated non forward-projecting jaws further back than previous discoveries, the facial structure of the Kenyanthropus and its derived features were very different of that of the Paranthropus, including almost every cranial feature. This gave no reason to assign the new skull in the genus Paranthropus and it is still thought that the differences in cranial structure are too different for even that to be a possibility. The Kenyanthropus also shows many differences to Homo, as well as Ardipithecus, having smaller molars at the date they existed, it is possible that the previous sister taxon of all modern hominins, Preanthropus afarensis, should be replaced by Kenyanthropus. Fragmentary specimens which were having trouble being classified are now being assessed to see if they fit with the Kenyanthropus, the Kenyanthropus platyops was examined by Collard and Wood to have two types of characteristics categorized as craniometric and traditional. Craniometric characters represent size-adjusted linear measurements between standard cranial landmarks, traditional characters represent those most commonly used in systematic studies of apes and early hominids. These characters can be quantitative and qualitative, Kenyanthropus platyops was singled out by the morphology of the maxilla, characterized by a flat and relatively orthognathic subnasal region, an anteriorly placed zygomatic process and small molars
34.
Paranthropus
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Paranthropus is a genus of extinct hominins. Also known as robust australopithecines, they were bipedal hominids that probably descended from the gracile australopithecine hominids 2.7 million years ago, however, Paranthropus skulls lack the transverse cranial crests that are also present in modern gorillas. A partial cranium and mandible of Paranthropus robustus was discovered in 1938 by a schoolboy, Gert Terblanche and it was described as a new genus and species by Robert Broom of the Transvaal Museum. The site has been excavated since 1993 by Francis Thackeray of the Transvaal Museum, a date of at least 1.95 million years has been obtained for Kromdraai B. Paranthropus boisei was discovered by Mary Leakey on July 17,1959, Mary was working alone, as Louis Leakey was ill in camp. She rushed back to camp and, at the news, Louis made a remarkable recovery and they refrained from excavating until Des Bartlett had photographed the site. In his notes Louis recorded a first name, Titanohomo mirabilis, Louis and Mary began to call it Dear Boy. Recovery was halted on August 7, Dear Boy was found in context with Oldowan tools and animal bones. The fossil was published in Nature dated August 15,1959, in it Louis placed the fossil in Brooms Australopithecinae family, creating a new genus for it, Zinjanthropus, species boisei. Zinj is an ancient Arabic word for the coast of East Africa and boisei referred to Charles Watson Boise, Louis based his classification on twenty differences from Australopithecus. Broom had died in 1951 but Dart was still living and he is said to have wept for joy on Louis behalf on being personally shown Zinj, which Louis and Mary carried around in a tin. Louis had considered Brooms Paranthropus genus, but rejected it because he believed Zinj was in the Homo ancestral stock and he relied heavily on the larger size of Zinjs canines. At that time palaeoanthropology was in a mood to lump and was preaching against splitting. Dart rescued him with the now famous joke, what would have happened if Mrs. Ples had met Dear Boy one dark night. The battle of the name raged on for years and drove a wedge between Louis and Sir Wilfrid LeGros Clark, from 1955, who took the Paranthropus view. On the other hand, it brought the Leakeys and Dr. Melville Bell Grosvenor of the National Geographic Society together, the Leakeys became international figures and had no trouble finding funds from then on. The Zinj question ultimately became part of the Australopithecus/Paranthropus question, all species of Paranthropus were bipedal, and many lived during a time when species of the genus Homo, were prevalent. Paranthropus first appeared roughly 2.7 million years ago, most species of Paranthropus had a brain about 40 percent of the size of a modern human
35.
Ardipithecus
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Ardipithecus is a genus of an extinct hominine that lived during Late Miocene and Early Pliocene in Afar Depression, Ethiopia. Two fossil species are described in the literature, A. ramidus, which lived about 4.4 million years ago during the early Pliocene, behavioral analysis showed that Ardipithecus could be very similar to chimpanzees, indicating that the early human ancestors were very chimpanzee-like in behaviour. A. ramidus was named in September 1994, the first fossil found was dated to 4.4 million years ago on the basis of its stratigraphic position between two volcanic strata, the basal Gaala Tuff Complex and the Daam Aatu Basaltic Tuff. The name Ardipithecus ramidus stems mostly from the Afar language, in which Ardi means ground/floor, the pithecus portion of the name is from the Greek word for ape. Like most hominids, but unlike all previously recognized hominins, it had a grasping hallux or big toe adapted for locomotion in the trees and it is not confirmed how much other features of its skeleton reflect adaptation to bipedalism on the ground as well. Like later hominins, Ardipithecus had reduced canine teeth, more fragments were recovered in 1994, amounting to 45% of the total skeleton. This fossil was described as a species of Australopithecus, but White. Between 1999 and 2003, a team led by Sileshi Semaw discovered bones. The fossils were dated to between 4.35 and 4.45 million years old, Ardipithecus ramidus had a small brain, measuring between 300 and 350 cm3. Like common chimpanzees, A. ramidus was much more prognathic than modern humans, the size of the upper canine tooth in A. ramidus males was not distinctly different from that of females. The features of the canine in A. ramidus contrast with the sexual dimorphism observed in common chimpanzees. The less pronounced nature of the canine teeth in A. ramidus has been used to infer aspects of the social behavior of the species. In particular, it has used to suggest that the last common ancestor of hominids. This is markedly different from social patterns in common chimpanzees, among which intermale, researchers in a 2009 study said that this condition compromises the living chimpanzee as a behavioral model for the ancestral hominid condition. A. ramidus existed more recently than the most recent common ancestor of humans and chimpanzees, nevertheless, it is in some ways unlike chimpanzees, suggesting that the common ancestor differs from the modern chimpanzee. After the chimpanzee and human lineages diverged, both underwent substantial evolutionary change, chimp feet are specialized for grasping trees, A. ramidus feet are better suited for walking. The canine teeth of A. ramidus are smaller, and equal in size between males and females, which suggests reduced male-to-male conflict, increased pair-bonding, and increased parental investment. Thus, fundamental reproductive and social behavioral changes probably occurred in long before they had enlarged brains and began to use stone tools
36.
Sahelanthropus
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Sahelanthropus tchadensis is an extinct homininae species that is dated to about 7 million years ago, during the Miocene epoch, possibly very close to the time of the chimpanzee–human divergence. Few specimens are known, other than the partial skull nicknamed Toumaï, existing fossils include a relatively small cranium named Toumaï, five pieces of jaw, and some teeth, making up a head that has a mixture of derived and primitive features. The braincase, being only 320 cm³ to 380 cm³ in volume, is similar to that of extant chimpanzees and is less than the approximate human volume of 1350 cm³. The teeth, brow ridges, and facial structure differ markedly from those found in Homo sapiens, cranial features show a flatter face, u-shaped dental arcade, small canines, an anterior foramen magnum, and heavy brow ridges. No postcranial remains have been recovered, the only known skull suffered a large amount of distortion during the time of fossilisation and discovery, as the cranium is dorsoventrally flattened, and the right side is depressed. Sahelanthropus tchadensis may have walked on two legs, upon examination of the foramen magnum in the primary study, the lead author speculated that a bipedal gait would not be unreasonable based on basicranial morphology similar to more recent hominins. Further, according to recent information, what might be a femur of a hominid was also discovered near the cranium—but which has not been published nor accounted for. All known material of Sahelanthropus was found between July 2001 and March 2002 at three sites, TM247, TM266, which yielded most of the material, including a cranium and a femur, and TM292. The discoverers claimed that S. tchadensis is the oldest known human ancestor after the split of the line from that of chimpanzees. The bones were found far from most previous hominin fossil finds, however, an Australopithecus bahrelghazali mandible was found in Chad by Mamelbaye Tomalta, Najia and Alain Beauvilain, Michel Brunet and Aladji H. E. With the sexual dimorphism known to have existed in early hominins, Sahelanthropus may represent a common ancestor of humans and chimpanzees, though no consensus has been reached yet by the scientific community. The original placement of species as a human ancestor but not a chimpanzee ancestor would complicate the picture of human phylogeny. Another possibility is that Toumaï is related to humans and chimpanzees, but is the ancestor of neither. Brigitte Senut and Martin Pickford, the discoverers of Orrorin tugenensis, even if this claim is upheld the find would lose none of its significance, because at present, very few chimpanzee or gorilla ancestors have been found anywhere in Africa. Thus if S. tchadensis is a relative of the chimpanzees or gorillas. And S. tchadensis does indicate that the last common ancestor of humans and chimpanzees is unlikely to closely resemble extant chimpanzees, indeed, some researchers consider suggestions that Sahelanthropus is too early to be a human ancestor to have evaporated. Sediment isotope analysis of atoms in the fossil yielded an age of about 7 million years. In fact, Toumaï may have been reburied in the recent past, taphonomic analysis reveals the likelihood of one, perhaps two, burial
37.
Orrorin
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Orrorin tugenensis is a postulated early species of Homininae, estimated at 6.1 to 5.7 million years and discovered in 2000. It is not confirmed how Orrorin is related to modern humans and its discovery was an argument against the hypothesis that australopithecines are human ancestors, as much as it still remains the most prevalent hypothesis of human evolution as of 2012. The name of genus Orrorin means original man in Tugen, and the name of the only classified species, O. tugenensis, derives from Tugen Hills in Kenya, as of 2007,20 fossils of the species have been found. Orrorin had small teeth relative to its body size and its dentition differs from that found in Australopithecus in that its cheek teeth are smaller and less elongated mesiodistally and from Ardipithecus in that its enamel is thicker. The dentition differs from both species in the presence of a mesial groove on the upper canines. The canines are ape-like but reduced, like those found in Miocene apes, Orrorin had small post-canines and was microdont, like modern humans, whereas robust australopithecines were megadont. In the femur, the head is spherical and rotated anteriorly, the neck is elongated and oval in section, while these suggest that Orrorin was bipedal, the rest of the postcranium indicates it climbed trees. After the fossils were found in 2000, they were held at the Kipsaraman village community museum, since then, according to the Community Museums of Kenya chairman Eustace Kitonga, the fossils are stored at a secret bank vault in Nairobi. The main similarity is that the Orrorin femur is morphologically closer to that of H. sapiens than is Lucys, there is, however, some debate over this point. Other fossils found in the Lukeino Formation show that Orrorin lived in a dry evergreen forest environment, the team that found these fossils in 2000 was led by Brigitte Senut and Martin Pickford from the Muséum national dhistoire naturelle. This date is markedly different from those using the molecular clock approach. Life timeline List of human evolution fossils Martin Pickford Orrorin tugenensis - The Smithsonian Institutions Human Origins Program Human Timeline – Smithsonian, National Museum of Natural History
38.
Tribe (biology)
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In biology, a tribe is a taxonomic rank above genus, but below family and subfamily. It is sometimes subdivided into subtribes, in zoology, some examples include the tribes Caprini, Hominini, Bombini, and Thunnini. The standard ending for the name of a tribe is -ini. The tribe Hominini is divided into subtribes by some scientists, subtribe Hominina then comprises humans, the standard ending for the name of a zoological subtribe is -ina. In botany, examples include the tribes Acalypheae and Hyacintheae, the standard ending for the name of a botanical tribe is -eae. The tribe Hyacintheae is divided into subtribes, including the subtribe Massoniinae, the standard ending for the name of a botanical subtribe is -inae. In bacteriology, the form of names is as in botany, e. g. Pseudomonadeae
39.
Gorilla
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Gorillas are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. The eponymous genus Gorilla is divided into two species, the gorillas and the western gorillas, and either four or five subspecies. They are the largest living primates, the DNA of gorillas is highly similar to that of humans, from 95–99% depending on what is counted, and they are the next closest living relatives to humans after the chimpanzees and bonobos. Gorillas natural habitats cover tropical or subtropical forests in Africa, although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. The mountain gorilla inhabits the Albertine Rift montane cloud forests of the Virunga Volcanoes, ranging in altitude from 2, 200–4,300 metres. The word gorilla comes from the history of Hanno the Navigator, members of the expedition encountered a savage people, the greater part of whom were women, whose bodies were hairy, and who our interpreters called Gorillae. The word was later used as the species name, though it is unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys. The American physician and missionary Thomas Staughton Savage and naturalist Jeffries Wyman first described the gorilla in 1847 from specimens obtained in Liberia. The name was derived from Ancient Greek Γόριλλαι, meaning tribe of hairy women, the closest relatives of gorillas are the other two Homininae species, chimpanzees and humans, all of them having diverged from a common ancestor about 7 million years ago. Human gene sequences differ only 1. 6% on average from the sequences of corresponding gorilla genes, until recently, gorillas were considered to be a single species, with three subspecies, the western lowland gorilla, the eastern lowland gorilla and the mountain gorilla. There is now agreement that there are two species, each with two subspecies, more recently, a third subspecies has been claimed to exist in one of the species. The separate species and subspecies developed from a type of gorilla during the Ice Age. Primatologists continue to explore the relationships between various gorilla populations, the species and subspecies listed here are the ones upon which most scientists agree. The proposed third subspecies of Gorilla beringei, which has not yet received a trinomen, is the Bwindi population of the mountain gorilla, some variations that distinguish the classifications of gorilla include varying density, size, hair colour, length, culture, and facial widths. Now, over 100,000 western lowland gorillas are thought to exist in the wild, with 4,000 in zoos, mountain gorillas are the most severely endangered, with an estimated population of about 880 left in the wild and none in zoos. Population genetics of the lowland gorillas suggest that the western and eastern lowland populations diverged ~261 thousand years ago, gorillas move around by knuckle-walking, although they sometimes walk bipedally for short distances while carrying food or in defensive situations. Wild male gorillas weigh 135 to 180 kg while females usually weigh half as much as adult males at 70–115 kg. Adult males are 1.7 to 1.8 m tall, female gorillas are shorter, with smaller arm spans
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Chimpanzee-human last common ancestor
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The chimpanzee–human last common ancestor, or CHLCA, is the last common ancestor shared by the extant Homo and Pan genera of Hominini. Due to complex hybrid speciation, it is not possible to give an estimate on the age of this ancestral individual. While original divergence between populations may have occurred as early as 13 million years ago, hybridization may have been ongoing until as recent as 4 million years ago, speciation from Pan to Homo appears to have been a long, drawn-out process. The latter date and the argument for hybridization events are rejected by Wakeley, however, to date no fossil has been identified as a probable candidate for the CHLCA or the taxon Pan prior. The earliest studies of apes suggested the CHLCA may have been as old as 25 million years, however, genetic methods based on orangutan–human and gibbon–human LCA times were then used to estimate a chimpanzee–human LCA of 5 to 7 million years. Some researchers tried to estimate the age of the CHLCA using biopolymer structures that differ slightly between closely related animals, among these researchers, Allan C. Wilson and Vincent Sarich were pioneers in the development of the molecular clock for humans. Working on protein sequences they eventually determined that apes were closer to humans than some paleontologists perceived based on the fossil record. Later, Vincent Sarich concluded that the TCHLCA was no greater than 8 million years in age and this paradigmatic age has stuck with molecular anthropology until the late 1990s. An estimate of TCHLCA at 10 to 13 million years was proposed in 1998, 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. This conclusion was rejected as unwarranted by Wakeley, who suggested alternative explanations, such a scenario would explain why the divergence age between the Homo and Pan has varied with the chosen method and why a single point has so far been hard to track down. The taxon tribe Hominini was proposed on basis of the idea that, regarding a trichotomy, originally, this produced a separated Homo genus, which, predictably, was deemed the most different among the three genera that includes Pan and Gorilla. However, later discoveries and analyses revealed that Pan and Homo are closer genetically than are Pan and Gorilla, thus, Gorilla now became the separated genus and was referred to the new taxon tribe Gorillini. Mann and Weiss, proposed that the tribe Hominini should encompass Pan as well as Homo and they would classify Homo and all bipedal apes to the subtribe Hominina and Pan to the subtribe Panina. Richard Wrangham argued that the CHLCA species was similar to chimpanzees — so much so that it should be classified as a member of the Pan genus. To date, no fossil has been identified as a candidate for the CHLCA or the taxon Pan prior. Such grouping represents the clade and its members are called hominins. A chimpanzee clade was posited by Wood and Richard, who referred it to a Tribe Panini, few fossil specimens on the chimpanzee-side of the split have been found, the first fossil chimpanzee, dating between 545 and 284 kyr, was discovered in Kenyas East African Rift Valley. All extinct genera listed in the taxobox are ancestral to Homo, however, both Orrorin and Sahelanthropus existed around the time of the divergence, and so either one or both may be ancestral to both genera Homo and Pan
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Bipedalism
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Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that moves in a bipedal manner is known as a biped /ˈbaɪpɛd/. Types of bipedal movement include walking, running, or hopping, few modern species are habitual bipeds whose normal method of locomotion is two-legged. A larger number of modern species intermittently or briefly use a bipedal gait, several non-archosaurian lizard species move bipedally when running, usually to escape from threats. Many primate and bear species will adopt a bipedal gait in order to reach food or explore their environment, several arboreal primate species, such as gibbons and indriids, exclusively walk on two legs during the brief periods they spend on the ground. Many animals rear up on their hind legs whilst fighting or copulating, some animals commonly stand on their hind legs, in order to reach food, to keep watch, to threaten a competitor or predator, or to pose in courtship, but do not move bipedally. The word is derived from the Latin words bi two and ped- foot, as contrasted with quadruped four feet, limited and exclusive bipedalism can offer a species several advantages. While upright, non-locomotory limbs become free for other uses, including manipulation, flight, digging, even though bipedalism is slower at first, over long distances, it has allowed humans to outrun most other animals according to the endurance running hypothesis. Bipedality in kangaroo rats has been hypothesized to improve locomotor performance, zoologists often label behaviors, including bipedalism, as facultative or obligate. Even this distinction is not completely clear-cut — for example, humans other than infants normally walk and run in biped fashion, but almost all can crawl on hands and knees when necessary. Even if one ignores exceptions caused by some kind of injury or illness, there are many cases, including the fact that normal humans can crawl on hands. This article therefore avoids the terms facultative and obligate, and focuses on the range of styles of locomotion used by various groups of animals. There are a number of states of movement commonly associated with bipedalism, in most bipeds this is an active process, requiring constant adjustment of balance. One foot in front of another, with at least one foot on the ground at any time, one foot in front of another, with periods where both feet are off the ground. Moving by a series of jumps with both feet moving together, the great majority of living terrestrial vertebrates are quadrupeds, with bipedalism exhibited by only a handful of living groups. Humans, gibbons and large birds walk by raising one foot at a time, on the other hand, most macropods, smaller birds, lemurs and bipedal rodents move by hopping on both legs simultaneously. Tree kangaroos are able to walk or hop, most commonly alternating feet when moving arboreally, there are no known living or fossil bipedal amphibians. Many species of lizards become bipedal during high-speed, sprint locomotion, including the worlds fastest lizard, the first known biped is the bolosaurid Eudibamus whose fossils date from 290 million years ago
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Human taxonomy
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Human taxonomy is the classification of the species Homo sapiens, or the modern hominin, humans. Homo, the genus, includes the past genetic tree of humanity, with Neanderthals, Denisovans. H. sapiens is the surviving species of the genus Homo. Extinct Homo species include archaic humans, current humans have been designated as subspecies Homo sapiens sapiens, differentiated from the direct ancestor, Homo sapiens idaltu. Prior to the current scientific classification of humans, philosophers and scientists have made attempts to classify humans. They offered definitions of the human being and schemes for classifying types of humans, biologists once classified races as subspecies, but today anthropologists reject the concept of race and view humanity as an interrelated genetic continuum. Taxonomy of the hominins continues to evolve, generally, humans are considered the only surviving representatives of the genus Homo. Scientists have also debated whether any other branches of Homo, such as Neanderthals and these distinctions are connected with two competing theories of human origins, the more common recent single-origin hypothesis and the multiregional hypothesis. Modern humans have some genes that originally arose in archaic human populations, human taxonomy has involved both placing humans within the hominid family and classifying types of humans within the species. As recorded in the Hebrew Bible, ancient Hebrews classified humans as a kind of living soul, living things were said to beget their own kind, a group broader than the scientific species. Humans were said to comprise a single kind, humans have long been considered animals. Plato referred to humans as featherless biped animals, and Aristotle defined the human being as the animal or the political animal. Classic and medieval taxonomy grouped living things according to characteristics, modern taxonomy, on the other hand, classifies organisms according to evolutionary lines of descent. Current opposition to classifying humans as animals arises from this definition of what it means to be an animal. When Linnaeus defined humans as Homo sapiens in 1758, they were the members of the genus Homo. The first other species to be classified a Homo was H. neanderthalensis, since then, ten additional extinct species have been classified as Homo. In a common misunderstanding of evolutionary theory, each represents a stage in the evolutionary track, some more evolved. Based on this misunderstanding, scientists thought of humans as having descended from apes and expected to find the missing link
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Cladogram
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A cladogram is a diagram used in cladistics to show relations among organisms. A cladogram uses lines that branch off in different directions ending at a clade, there are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off and these branching off points represent a hypothetical ancestor which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of features, adaptation. The characteristics used to create a cladogram can be categorized as either morphological or molecular. Prior to the advent of DNA sequencing, cladistic analysis primarily used morphological data, behavioral data may also be used. As DNA sequencing has become cheaper and easier, molecular systematics has become a more and more popular way to infer phylogenetic hypotheses. Another powerful method of reconstructing phylogenies is the use of genomic retrotransposon markers, researchers must decide which character states are ancestral and which are derived, because only synapomorphic character states provide evidence of grouping. This determination is usually done by comparison to the states of one or more outgroups. States shared between the outgroup and some members of the in-group are symplesiomorphies, states that are present only in a subset of the in-group are synapomorphies, note that character states unique to a single terminal do not provide evidence of grouping. The choice of an outgroup is a step in cladistic analysis because different outgroups can produce trees with profoundly different topologies. A homoplasy is a state that is shared by two or more taxa due to some cause other than common ancestry. The two main types of homoplasy are convergence and reversion, however, homoplasy is often not evident from inspection of the character itself, and is then detected by its incongruence on a most-parsimonious cladogram. Note that characters that are homoplastic may still contain phylogenetic signal, a well-known example of homoplasy due to convergent evolution would be the character, presence of wings. Though the wings of birds, bats, and insects serve the function, each evolved independently. Of course, the reason a homoplasy is recognizable in the first place is because there are other characters that imply a pattern of relationships that reveal its homoplastic distribution. A cladogram is the result of a parsimony analysis, which groups taxa on the basis of synapomorphies alone. There are many other algorithms that treat data somewhat differently
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Clade
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A clade is a group of organisms that consists of a common ancestor and all its lineal descendants, and represents a single branch on the tree of life. The common ancestor may be an individual, a population, a species, clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently, over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades, the term clade was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis, a concept Huxley borrowed from Bernhard Rensch. Many commonly named groups are clades, for example, rodents or insects, because in each case, their name refers to a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago, the original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta and these clades include smaller clades, such as chipmunk or ant, each of which consists of even smaller clades. The clade rodent is in included in the mammal, vertebrate. The phenomenon of convergent evolution is, however, responsible for cases where there are misleading similarities in the morphology of groups that evolved from different lineages. The publication of Darwins theory of evolution in 1859 gave this view increasing weight, thomas Henry Huxley, an early advocate of evolutionary theory, proposed a revised taxonomy based on clades. For example, he grouped birds with reptiles, based on fossil evidence, german biologist Emil Hans Willi Hennig is considered to be the founder of cladistics. Taxonomists have increasingly worked to make the taxonomic system reflect evolution, when it comes to naming, however, this principle is not always compatible with the traditional rank-based nomenclature. For these and other reasons, phylogenetic nomenclature has been developed, a clade is by definition monophyletic, meaning that it contains one ancestor and all its descendants. The ancestor can be known or unknown, any and all members of a clade can be extant or extinct, the science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics, the latter term coined by Ernst Mayr, derived from clade. The results of analyses are tree-shaped diagrams called cladograms, they. Three methods of defining clades are featured in phylogenetic nomenclature, node-, stem-, the relationship between clades can be described in several ways, A clade located within a clade is said to be nested within that clade. In the diagram, the clade, i. e. the apes. Two clades are sisters if they have a common ancestor
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Superfamily (zoology)
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In biological classification, rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, a given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms, the rank of any species and the description of its genus is basic, which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two. Consider a particular species, the red fox Vulpes vulpes, its next rank, as one group of the class Mammalia, all of the above are classified among those with backbones in the Chordata phylum rank, and with them among all the animals in the Animalia kingdom rank. Finally, all of the above will find their earliest relatives somewhere in their domain rank Eukarya, today, nomenclature is regulated by the nomenclature codes. There are seven main ranks, kingdom, phylum or division, class, order, family, genus. In addition, the domain is now used as one of the fundamental ranks. Also, this represents a synonym for the category of dominion. Unlike Moore, Whoese et al. did not suggest a Latin term for this category, a taxon is usually assigned a rank when it is given its formal name. The basic ranks are species and genus, when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. The species name is called a binomial, that is. For example, the name for the human species is Homo sapiens. This is usually italicized in print and underlined when italics are not available, in this case, Homo is the generic name and it is capitalized, sapiens indicates the species and it is not capitalized. There are definitions of the taxonomic ranks in the International Code of Zoological Nomenclature, superfamily, family, subfamily, tribe, subtribe, genus, subgenus. The International Code of Zoological Nomenclature divides names into family-group names, genus-group names, in the genus group and species group no further ranks are allowed. At higher ranks a lower level may be denoted by adding the prefix infra, meaning lower, a taxon above the rank of species has a scientific name in one part. A species has a composed of two parts, generic name + specific name, for example Canis lupus. A subspecies has a composed of three parts, generic name + specific name + subspecific name, for example Canis lupus familiaris
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Family (taxonomy)
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In biological classification, family is one of the eight major taxonomic ranks, it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. In vernacular usage, a family may be named one of its common members, for example, walnuts and hickory trees belong to the family Juglandaceae. What does or does not belong to a family—or whether a family should be recognized at all—are proposed and determined by practicing taxonomists. There are no rules for describing or recognizing a family. Taxonomists often take different positions about descriptions of taxa, and there may be no broad consensus across the community for some time. Some described taxa are accepted broadly and quickly, but others only rarely, if at all, the naming of families is codified by various international codes. In zoological nomenclature, the names of animals end with the suffix -idae. The concept of rank at time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera. Carolus Linnaeus used the word familia in his Philosophia botanica to denote groups of plants, trees, herbs, ferns, palms. He used this term only in the section of the book. In zoology, the family as an intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes. He used families in some but not in all his orders of insects, families can be used for evolutionary, palaeontological and generic studies because they are more stable than lower taxonomic levels such as genera and species
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Tribe (taxonomy)
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In biology, a tribe is a taxonomic rank above genus, but below family and subfamily. It is sometimes subdivided into subtribes, in zoology, some examples include the tribes Caprini, Hominini, Bombini, and Thunnini. The standard ending for the name of a tribe is -ini. The tribe Hominini is divided into subtribes by some scientists, subtribe Hominina then comprises humans, the standard ending for the name of a zoological subtribe is -ina. In botany, examples include the tribes Acalypheae and Hyacintheae, the standard ending for the name of a botanical tribe is -eae. The tribe Hyacintheae is divided into subtribes, including the subtribe Massoniinae, the standard ending for the name of a botanical subtribe is -inae. In bacteriology, the form of names is as in botany, e. g. Pseudomonadeae
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Old World monkey
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The Old World monkeys or Cercopithecidae are a family of catarrhines, the only family in the superfamily Cercopithecoidea in the clade of Catarrhini. However, a group of monkeys still survives in Gibraltar to this day. Old World monkeys include many of the most familiar species of primates, such as baboons. Old World monkeys are medium to large in size, and range from arboreal forms, such as the monkeys, to fully terrestrial forms. By superficial appearance, Old World monkeys are unlike apes in that most have tails and, unlike the New World monkeys, technically, the distinction of catarrhines from platyrrhines depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In platyrrhines, the nostrils face sideways, while in catarrhines, for example, the colobus monkeys have stubs for thumbs to assist with their arboreal movement, the proboscis monkey has an extraordinary nose, while the snub-nosed monkeys have almost no nose at all. The male mandrills penis is red and the scrotum is lilac, the coloration is more pronounced in dominant males. Most Old World monkeys are at least partially omnivorous, but all prefer plant matter, the Barbary macaques diet consists mostly of leaves and roots, though it will also eat insects and uses cedar trees as a water source. Gestation in the Old World monkeys lasts between five and seven months, births are usually single, although, as with humans, twins occur from time to time. The young are born relatively well-developed, and are able to cling onto their mothers fur with their hands from birth, compared with most other mammals, they take a long time to reach sexual maturity, with four to six years being typical of most species. In most species, daughters remain with their mothers for life, males leave the group on reaching adolescence, and find a new troop to join. In many species, only an adult male lives with each group, driving off all rivals. Group sizes are variable, even within species, depending on the availability of food. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey
. PMID 20445105.
