1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
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
13.
North American porcupine
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The North American porcupine, also known as the Canadian porcupine or common porcupine, is a large rodent in the New World porcupine family. The beaver is the rodent in North America that is larger than the North American porcupine. The word porcupine comes from the middle or old French word porcespin and its roots derive from the Latin words porcus or pig and spina meaning thorns. Other colloquial names for the animal include quill pig and it is also referred to as the Canadian porcupine or common porcupine. The porcupines scientific name, Erethizon dorsatum, can be translated as the animal with the irritating back. Several Native American names exist, such as the Lakota name pahin meaning quill, the North American porcupine migrated from South America, where all New World porcupines or hystricomorphs evolved. Erethizon appeared in North America shortly after the two joined together in the later Tertiary period. Other hystricomorphs also migrated, but Erethizon was the one to survive north of Mexico. No known fossils are attributed to prior to the late Tertiary period. Some fossils, such as species from the family Paramyidae, show resemblance to the porcupine, South American hystricomorphs first appeared in the Lower Oligocene period. They are thought to have migrated from Africa, ancestors of the Old World porcupines or Hystricidae or they originated based on a migration of the North American Paramyidae. The earliest appearance of E. dorsatum is from the Pleistocene era found along the Arroyo del Cedazo near Aguascalientes, seven subspecies of E. dorsatum are recognized. They are subdivided by different ranges across North America, by far the most common is E. d. dorsatum, which ranges from Nova Scotia to Alberta and from Virginia to the Yukon. E. d. picinum occupies a range in northeastern Quebec. E. d. couesi is the most southern ranging from northern Mexico to Colorado, E. d. bruneri can be found in the midwest from Arkansas to Montana. The last three are western species, from south to north they are E. d. epixanthum, E. d. nigrescens, and E. d. myops. Porcupines are usually brown or black in color, with white highlights. They have a body, a small face, short legs
14.
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
15.
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
16.
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
17.
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
18.
Rodent
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Rodents are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all species are rodents, they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, Species can be arboreal, fossorial, or semiaquatic. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, hamsters, and capybaras. Other animals such as rabbits, hares, and pikas, whose incisors also grow continually, were included with them, but are now considered to be in a separate order. Nonetheless, Rodentia and Lagomorpha are sister groups, sharing a most recent common ancestor, most rodents are small animals with robust bodies, short limbs, and long tails. They use their incisors to gnaw food, excavate burrows. Most eat seeds or other plant material, but some have more varied diets and they tend to be social animals and many species live in societies with complex ways of communicating with each other. Mating among rodents can vary from monogamy, to polygyny, to promiscuity, many have litters of underdeveloped, altricial young, while others are precocial at birth. The rodent fossil record back to the Paleocene on the supercontinent of Laurasia. Rodents greatly diversified in the Eocene, as spread across continents. Rodents reached both South America and Madagascar from Africa, and were the only placental mammals to reach. Rodents have been used as food, for clothing, as pets, some species, in particular the brown rat, the black rat, and the house mouse, are serious pests, eating and spoiling food stored by humans, and spreading diseases. The distinguishing feature of the rodents is their pairs of continuously growing and these incisors have thick layers of enamel on the front and little enamel on the back. Because they do not stop growing, the animal must continue to wear them down so that they do not reach and pierce the skull. As the incisors grind against each other, the softer dentine on the rear of the teeth wears away, most species have up to 22 teeth with no canines or anterior premolars. A gap, or diastema, occurs between the incisors and the teeth in most species. This allows rodents to suck in their cheeks or lips to shield their mouth and throat from wood shavings and other inedible material, chinchillas and guinea pigs have a high-fiber diet, their molars have no roots and grow continuously like their incisors
19.
Hystricognathi
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The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis passes partially through the foramen and connects to the bone on the opposite side. This, together with their lack of a plate and the relative size of the infraorbital foramen. The 18 families within the Hystricognathi are divided into two infraorders, the Phiomorpha and the Caviomorpha, the Caviomorpha are mostly native to South America, with a few species in North America, while the Phiomorpha occur in the Old World. Play behavior has been observed in seven hystricognath families, the caviomorphs chase each other, play-wrestle, and gallop. The longer-legged species chase more often than the shorter-legged species and they also rotate their heads and body muscles as a form of play
20.
Caviomorpha
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Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence, the Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now accepted as a genuine part of the rodents. By the late Oligocene, all superfamilies and most families of caviomorphs are present in the fossil record, during this time, South America was isolated from all other continents. Several hypotheses have proposed as to how hystricognath rodents colonized this island continent. Most require that a group of these rodents traveled across ocean bodies atop a raft of mangroves or driftwood. The most common hypothesis suggests that the ancestor to all modern caviomorphs rafted across the Atlantic Ocean from Africa and this is supported by molecular results, which suggest that the Phiomorpha are sister taxa to the Caviomorpha. In fact, until the discovery of the Laotian rock rat, all modern hystricognath families were restricted to South America, Africa, the principal alternative hypothesis is that the caviomorph ancestor arose in Asia and migrated to South America through another continent. Fossil evidence suggests the Entodacrya may have originated in Asia and this is cited as evidence for an Asian origin for Caviomorpha as well. Likewise, Jenkins et al. argue that their discovery of a rodent family exclusive to Asia may be further evidence for an Asian origin of caviomorphs. Alternatively, the caviomorphs may have originated in Asia, but traveled through Africa, Australia and Antarctica, alternatively they may have originated in Africa and traveled to South America via Antarctica. New World monkeys appear to have colonized South America from Africa at a similar time, caviomorphs went on to colonize the West Indies as far as the Bahamas, reaching the Greater Antilles by the early Oligocene. This is commonly viewed as another example of oceanic dispersal, although a role for a land bridge has also been considered. Caviomorph rodents underwent an explosive diversification upon arrival into South America and they managed to outcompete other animals in rodent-like niches such as certain South American marsupials. Retaining predominantly herbivorous diets, they expanded their sizes to encompass a range from rat-sized echimyids to the bison-sized Phoberomys, habitats range from grasslands, high mountains, forest edges and dense tropical forests. The nutria has been introduced into North America and has proven a successful invasive species there. The Dinomyidae may belong to the Chinchilloidea, the Abrocomidae may belong to the Octodontoidea, huchon, D. E. J. P. Douzery. From the Old World to the New World, A molecular chronicle of the phylogeny, Jenkins, P. D. C. W. Kilpatrick, M. F. Robinson, and R. J. Timmins. Morphological and molecular investigations of a new family, genus and species of rodent from Lao PDR, la systématique des rongeurs hystricomorphes et la dérive des continents
21.
Charles Lucien Jules Laurent Bonaparte
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Charles Lucien Jules Laurent Bonaparte, 2nd Prince of Canino and Musignano, was a French biologist and ornithologist. Lucien and his wife had children, including Cardinal Lucien Bonaparte. Bonaparte was the son of Lucien Bonaparte and Alexandrine de Bleschamp, born in Paris, he was raised in Italy. On 29 June 1822, he married his cousin, Zénaïde, soon after the marriage, the couple left for Philadelphia in the United States to live with Zénaïdes father, Joseph Bonaparte. Before leaving Italy, Carlo had already discovered a new to science, the moustached warbler. On arrival in the United States, he presented a paper on this new bird, Bonaparte then set about studying the ornithology of the United States and updating Wilsons American Ornithology. The revised edition was published between 1825 and 1833, in 1824, Bonaparte tried to get the then unknown John James Audubon accepted by the Academy of Natural Sciences, but this was opposed by the ornithologist George Ord. At the end of 1826, Bonaparte and his family returned to Europe and he visited Germany, where he met Philipp Jakob Cretzschmar, and England, where he met John Edward Gray at the British Museum, and renewed his acquaintance with Audubon. In 1828, the family settled in Rome, in Italy, he was the originator of several scientific congresses, and lectured and wrote extensively on American and European ornithology and other branches of natural history. Between 1832 and 1841, Bonaparte published his work on the animals of Italy and he had also published Specchio Comparativo delle Ornithologie di Roma e di Filadelfia, presenting a comparison between birds of the latitude of Philadelphia and Italian species. He created the genus Zenaida, after his wife, for the mourning dove and he was elected a member of the American Antiquarian Society in 1845. In 1849, he was elected to the Roman Assembly and participated in the creation of the Roman Republic and he participated in the defense of Rome against the 40,000 French troops sent by his cousin Louis Napoleon. He left Rome after the Republican army was defeated in July 1849 and he landed at Marseilles, but was ordered to leave the country by Louis Napoleon. He reaffirmed his political beliefs the following year in naming Wilsons bird-of-paradise in honor of the republican idea and he travelled to England, attending the meeting of the British Association in Birmingham. He then visited Sir William Jardine in southern Scotland, Charles then began work on preparing a methodical classification of all the birds in the world, visiting museums across Europe to study the collections. In 1850, he was allowed to return to France and made Paris his home for the rest of his life, in 1854, he became director of the Jardin des Plantes. In 1855, he was made a member of the Royal Swedish Academy of Sciences. He published the first volume of his Conspectus Generum Avium before his death, Bonaparte also studied amphibians and reptiles, and is the author of Vipera ursinii, commonly known as Orsinis viper
22.
Prehensile-tailed porcupine
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The prehensile-tailed porcupines or coendous are found in Central and South America. Among the most notable features of Coendou porcupines are their unspined prehensile tails, the front and hind feet are also modified for grasping. These limbs all contribute to making this animal an adept climber and they feeds on leaves, shoots, fruits, bark, roots, and buds. They can be pests of plantation crops and they also make a distinctive baby-like sound to communicate in the wild. Young are born with hair that hardens to quills with age. Adults are slow-moving and will roll into a ball when threatened, the record longevity is 27 years. Rodents for comparative aging studies, from mice to beavers, nowak, Ronald M. Walkers Mammals of the World. Mammal Species of the World, A Taxonomic and Geographic Reference
23.
Arboreal locomotion
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Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them, some animals may scale trees only occasionally, but others are exclusively arboreal. Furthermore, many of these principles may be applied to climbing without trees. The earliest known tetrapod with specializations that adapted it for climbing trees was Suminia, some invertebrate animals are exclusively arboreal in habitat, such as the tree snail. Arboreal habitats pose numerous mechanical challenges to animals moving in them and these challenges include moving on narrow branches, moving up and down inclines, balancing, crossing gaps, and dealing with obstructions. Moving along a narrow surface poses special difficulties to animals, additionally, foot placement is constrained by the need to make contact with the narrow branch. This narrowness severely restricts the range of movements and postures an animal can use to move, branches are frequently oriented at an angle to gravity in arboreal habitats, including being vertical, which poses special problems. As an animal moves up a branch, they must fight the force of gravity to raise their body. Conversely, as the animal descends, it must also fight gravity to control its descent and prevent falling, descent can be particularly problematic for many animals, and highly arboreal species often have specialized methods for controlling their descent. Due to the height of many branches and the disastrous consequences of a fall. On horizontal and gently sloped branches, the problem is tipping to the side due to the narrow base of support. The narrower the branch, the greater the difficulty in balancing a given animal faces, on steep and vertical branches, tipping becomes less of an issue, and pitching backwards or slipping downwards becomes the most likely failure. In this case, large-diameter branches pose a challenge, since the animal cannot place its forelimbs closer to the center of the branch than its hindlimbs. Branches are not continuous, and any arboreal animal must be able to move between gaps in the branches, or even between trees and this can be accomplished by reaching across gaps, by leaping across them or gliding between them. Arboreal habitats often contain many obstructions, both in the form of branches emerging from the one being moved on and other branches impinging on the space the animal needs to move through and these obstructions may impede locomotion, or may be used as additional contact points to enhance it. While obstructions tend to impede limbed animals, they benefit snakes by providing anchor points, arboreal organisms display many specializations for dealing with the mechanical challenges of moving through their habitats. Arboreal animals frequently have elongated limbs that help them cross gaps, reach fruit or other resources, test the firmness of support ahead, however, some species of lizard have reduced limb size that helps them avoid limb movement being obstructed by impinging branches. Many arboreal species, such as porcupines, chameleons, silky anteaters, spider monkeys
24.
Spine (zoology)
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In a zoological context, a spine is a hard, needle-like anatomical structure. Spines are found in a range of animals both vertebrate and invertebrate. In most spiny mammals, the spines are modified hairs, with a spongy center covered in a thick, hard layer of keratin, spines in mammals include the prickles of hedgehogs and the quills of porcupines as well as the prickly fur of spiny mice and Tenrec. They are also found on Echidna, a monotreme, the ancient precursor to mammals, Dimetrodon, had extremely long spines on their backbone that were joined together with a web of skin to form a sail-like structure. Many mammalian species also have penile spines, the Mesozoic eutriconodont mammal Spinolestes already displayed spines similar to those of modern spiny mice. Spines are found in the rays of certain finned bony fishes including scorpion fish, the sting that is found in a stingray is a type of barbed spine. Spines are also found in animals, such as sea urchins. They are a feature of the shell of a number of different species of gastropod and bivalve mollusks, spines are also found in internal organs in invertebrates, such as the copulatory spines in the male or female organs of certain flatworms. In many cases, spines are a mechanism that help protect the animal against potential predators. Because spines are sharp, they can puncture skin and inflict pain, the spine of some animals are capable of injecting venom. In the case of large species of stingray, a puncture with the barbed spine. Animals such as porcupines are considered aposematic, because their spines warn predators that they are dangerous, porcupines rattle their quills as a warning to predators, much like rattlesnakes. Because many species of fish and invertebrates carry venom within their spines, venom can cause intense pain, and can sometimes result in death if left untreated. On the other hand, being pricked by a porcupine quill is not dangerous, the quill can be removed by gently but firmly pulling it out of the skin. The barbed tip sometimes breaks off, but it works its way out through the skin over time. e, through the nose Pens Some of the earliest pens were made from quills Sometimes, Brush
25.
Forest
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A forest is a large area dominated by trees. Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as density, tree height, land use, legal standing. According to the widely used Food and Agriculture Organization definition, forests covered four billion hectares or approximately 30 percent of the land area in 2006. Forests are the dominant terrestrial ecosystem of Earth, and are distributed across the globe, Forests account for 75% of the gross primary productivity of the Earths biosphere, and contain 80% of the Earths plant biomass. Forests at different latitudes and elevations form distinctly different ecozones, boreal forests near the poles, tropical forests near the equator, higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition. Human society and forests influence each other in both positive and negative ways, Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect peoples health, human activities, including harvesting forest resources, can negatively affect forest ecosystems. Although forest is a term of common parlance, there is no universally recognised precise definition, there are three broad categories of forest definitions in use, administrative, land use, and land cover. Land use definitions are based upon the purpose that the land serves. For example, a forest may be defined as any land that is used primarily for production of timber, land cover definitions define forests based upon the type and density of vegetation growing on the land. Such definitions typically define a forest as an area growing trees above some threshold and these thresholds are typically the number of trees per area, the area of ground under the tree canopy or the section of land that is occupied by the cross-section of tree trunks. Under such land cover definitions, and area of land only be defined as forest if it is growing trees, areas that fail to meet the land cover definition may be still included under while immature trees are establishing if they are expected to meet the definition at maturity. Under land use definitions, there is variation on where the cutoff points are between a forest, woodland, and savanna. Under some definitions, forests require high levels of tree canopy cover, from 60% to 100%, excluding savannas. Other definitions consider savannas to be a type of forest, the term was not endemic to Romance languages, and cognates in Romance languages, such as Italian foresta, Spanish and Portuguese floresta, etc. are all ultimately borrowings of the French word. The exact origin of Medieval Latin foresta is obscure, uses of the word forest in English to denote any uninhabited area of non-enclosure are now considered archaic. The word was introduced by the Norman rulers of England as a term denoting an uncultivated area legally set aside for hunting by feudal nobility. These hunting forests were not necessarily wooded much, if at all, however, as hunting forests did often include considerable areas of woodland, the word forest eventually came to mean wooded land more generally
26.
Old World porcupine
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The Old World porcupines, or Hystricidae, are large terrestrial rodents, distinguished by the spiny covering from which they take their name. They range over the south of Europe and the Levant, most of Africa, India, although both the Old World and New World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related. The habits of most species are strictly terrestrial, the various species are typically herbivorous, eating fruit, roots, and bulbs. Some species also gnaw on dry bones, perhaps as a source of calcium, like other rodents, they have powerful gnawing incisors, and no canine teeth. Their dental formula is 1.0.1.31.0.1.3 One or two young are born after a period between 90 and 112 days, depending on the species. Females typically give birth once a year, in a grass-lined underground chamber within a burrow system. The young are more or less fully developed, and the spines. Although they begin to take solid food within two weeks, they are not fully weaned until 13 to 19 weeks after birth. The young remain with the colony until they reach maturity at around two years of age, and share the burrow system with their parents and siblings from other litters. Males, in particular, help defend the colony from intruders, the crested porcupine, a typical representative of the Old World porcupines, occurs throughout the south of Europe and North and West Africa. It is replaced in South Africa by the Cape porcupine, H. africaeaustralis, the latter also lives throughout the Middle East. Besides these large-crested species, several smaller species without crests occur in northeast India, the genus Atherurus includes the brush-tailed porcupines which are much smaller animals, with long tails tipped with bundles of flattened spines. One species is found in the Malay region and one in Central, the latter species, the African brush-tailed porcupine, is often hunted for its meat. Trichys, the last genus, contains one species, the porcupine of Borneo. This species is very similar to Atherurus, but differs from the members of that genus in many cranial characteristics. Fossil species are known from Africa and Eurasia, with one of the oldest being Sivacanthion from the Miocene of present-day Pakistan. However, it was not a direct ancestor of modern porcupines. and Bell. Classification of Mammals Above the Species Level, columbia University Press, New York,631 pp. ISBN 0-231-11013-8
27.
Order (biology)
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In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, an immediately higher rank, superorder, may be added directly above order, while suborder would be a lower rank. A taxonomic unit, a taxon, in that rank, in that case the plural is orders. Example, The Juglans and Hickory trees belong to the family Juglandaceae, what does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no agreement, with different taxonomists each taking a different position. There are no rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognised only rarely, for some groups of organisms, consistent suffixes are used to denote that the rank is an order. The Latin suffix -formes meaning having the form of is used for the name of orders of birds and fishes. The suffix -ales is for the name of orders of plants, fungi, for some clades covered by the International Code of Zoological Nomenclature, a number of additional classifications are sometimes used, although not all of these are officially recognised. In their 1997 classification of mammals, McKenna and Bell used two levels between superorder and order, grandorder and mirorder. Michael Novacek inserted them at the same position, michael Benton inserted them between superorder and magnorder instead. This position was adopted by Systema Naturae 2000 and others, in botany, the ranks of subclass and suborder are secondary ranks pre-defined as respectively above and below the rank of order. Any number of further ranks can be used as long as they are clearly defined, the superorder rank is commonly used, with the ending -anae that was initiated by Armen Takhtajans publications from 1966 onwards. Carl Linnaeus was the first to apply it consistently to the division of all three kingdoms of nature in his Systema Naturae, for plants, Linnaeus orders in the Systema Naturae and the Species Plantarum were strictly artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups. In French botanical publications, from Michel Adansons Familles naturelles des plantes and until the end of the 19th century, some of the plant families still retain the names of Linnaean natural orders or even the names of pre-Linnaean natural groups recognised by Linnaeus as orders in his natural classification. Such names are known as family names. In zoology, the Linnaean orders were used more consistently and that is, the orders in the zoology part of the Systema Naturae refer to natural groups. Some of his names are still in use
28.
Molar (tooth)
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The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals and they are used primarily to grind food during chewing. The name molar derives from Latin, molaris dens, meaning tooth, from mola, millstone and dens. Molars show a great deal of diversity in size and shape across mammal groups, in humans, the molar teeth have either four or five cusps. Adult humans have twelve molars, in four groups of three at the back of the mouth, the third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of twenty, ethnicity can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all, the human mouth contains upper and lower molars. They are, maxillary first molar, maxillary second molar, maxillary third molar, mandibular first molar, mandibular second molar, in mammals, the crown of the molars and premolars are folded into a wide range of complex shapes. The basic elements of the crown are the more or less conical projections called cusps, the cusps contain both dentine and enamel, whereas minor projections on the crown, called crenullations, are the result of different enamel thickness. Cusps are occasionally joined to form ridges and expanded to form crests, cingula are often incomplete ridges that pass around the base of the crown. It is generally agreed that therian mammals evolved from an ancestor with tribosphenic cheek teeth, with three main cusps arranged in a triangle. Each major cusp on an upper molar is called a cone and is identified by a dependent on its relative location on the tooth, proto-, para-, meta-, hypo-. Suffixes are added to names, -id is added to cusps on a lower molar. A shelf-like ridge on the part of the crown is called a cingulum, the same feature on the lower molar a cingulid, and a minor cusp on these, for example. The design that is considered one of the most important characteristics of mammals is a shape called a tribosphenic molar. This molar design has two important features, the trigonid, or shearing end, and the talonid, or crushing heel, in modern tribosphenic molars, the trigonid is towards the front of the jaw and the talonid towards the rear. The tribosphenic tooth is found in insectivores and young platypuses, upper molars look like three-pointed mountain ranges, lowers look like two peaks and a third off to the side. The tribosphenic design appears primitively in all groups of mammals, some Jurassic mammals, such as Shuotherium and Pseudotribos, have reversed tribosphenic molars, in which the talonid is towards the front
29.
Prehensile tail
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A prehensile tail is the tail of an animal that has adapted to be able to grasp or hold objects. Fully prehensile tails can be used to hold and manipulate objects, if the tail cannot be used for this it is considered only partially prehensile - such tails are often used to anchor an animals body to dangle from a branch, or as an aid for climbing. The term prehensile means able to grasp, one point of interest is the distribution of animals with prehensile tails. The prehensile tail is predominantly a New World adaptation, especially among mammals, many more animals in South America have prehensile tails than in Africa and Southeast Asia. It has been argued that animals with prehensile tails are more common in South America because the forest there is denser than in Africa or Southeast Asia. In contrast, in dense forest such as in Southeast Asia it is observed that gliding animals such as colugos or flying snakes are more abundant. South American rainforests also differ by having more lianas, as there are large animals to eat them than in Africa and Asia. Tails are mostly a feature of vertebrates, however, some such as scorpions also have appendages that can be considered tails. However, only vertebrates are known to have developed prehensile tails, many mammals with prehensile tails will have a bare patch to aid gripping. This bare patch is known as a friction pad, many New World monkeys in the family Atelidae, which includes howler monkeys, spider monkeys and woolly monkeys, have grasping tails often with a bare tactile pad. This is in contrast with their distant Old World monkey cousins who do not have prehensile tails, a marsupial group from the Americas. There is anecdotal evidence that opossums may use their tails to carry nesting material. Anteaters are found in Central and South America, three of the four species of anteater, the Silky Anteater and the two species of tamandua, have prehensile tails Binturong. One of the few Old World animals with prehensile tails. The kinkajou of South and Central America is the other animal of the order Carnivora, besides the binturong. Another old world mammal, the Harvest Mouse also has a prehensile tail. Commonly found amongst areas of tall grasses such as crops, roadside verges, hedgerows, reedbeds. New World porcupines of the genera Coendou and Chaetomys have fully prehensile tails help them to climb
30.
Dentition
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Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the arrangement, kind. That is, the number, type, and morpho-physiology of the teeth of an animal, the dentition of animals with two successions of teeth is referred to as diphyodont, while the dentition of animals with only one set of teeth throughout life is monophyodont. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed polyphyodont, the mammalian pattern is significantly different. The teeth in the upper and lower jaws in mammals have evolved a relationship such that they operate together as a unit. All mammals except the monotremes, the xenarthrans, the pangolins, and these are the incisor, the canine, the premolar, and the molar. The incisors occupy the front of the row in both upper and lower jaws. They are normally flat, chisel-shaped teeth that meet in an edge-to-edge bite and their function is cutting, slicing, or gnawing food into manageable pieces that fit into the mouth for further chewing. The canines are immediately behind the incisors, in many mammals, the canines are pointed, tusk-shaped teeth, projecting beyond the level of the other teeth. In carnivores, they are offensive weapons for bringing down prey. In other mammals such as primates, they are used to split open hard surfaced food. The premolars and molars are at the back of the mouth, depending on the particular mammal and its diet, these two kinds of teeth prepare pieces of food to be swallowed by grinding, shearing, or crushing. The specialised teeth—incisors, canines, premolars, and molars—are found in the order in every mammal. In many mammals the infants have a set of teeth fall out and are replaced by adult teeth. These are called deciduous teeth, primary teeth, baby teeth or milk teeth, animals that have two sets of teeth, one followed by the other, are said to be diphyodont. Normally the dental formula for milk teeth is the same as for adult teeth except that the molars are missing, because mammal teeth are specialised for different functions, many mammal groups have lost teeth not needed in their adaptation. Tooth form has also undergone evolutionary modification as a result of selection for specialised feeding or other adaptations. Over time, different mammal groups have evolved distinct dental features, the number of teeth of each type is written as a dental formula for one side of the mouth, or quadrant, with the upper and lower teeth shown on separate rows
31.
Canada
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Canada is a country in the northern half of North America. Canadas border with the United States is the worlds longest binational land border, the majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer. Canada is sparsely populated, the majority of its territory being dominated by forest and tundra. It is highly urbanized with 82 per cent of the 35.15 million people concentrated in large and medium-sized cities, One third of the population lives in the three largest cities, Toronto, Montreal and Vancouver. Its capital is Ottawa, and other urban areas include Calgary, Edmonton, Quebec City, Winnipeg. Various aboriginal peoples had inhabited what is now Canada for thousands of years prior to European colonization. Pursuant to the British North America Act, on July 1,1867, the colonies of Canada, New Brunswick and this began an accretion of provinces and territories to the mostly self-governing Dominion to the present ten provinces and three territories forming modern Canada. With the Constitution Act 1982, Canada took over authority, removing the last remaining ties of legal dependence on the Parliament of the United Kingdom. Canada is a parliamentary democracy and a constitutional monarchy, with Queen Elizabeth II being the head of state. The country is officially bilingual at the federal level and it is one of the worlds most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Its advanced economy is the eleventh largest in the world, relying chiefly upon its abundant natural resources, Canadas long and complex relationship with the United States has had a significant impact on its economy and culture. Canada is a country and has the tenth highest nominal per capita income globally as well as the ninth highest ranking in the Human Development Index. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, Canada is an influential nation in the world, primarily due to its inclusive values, years of prosperity and stability, stable economy, and efficient military. While a variety of theories have been postulated for the origins of Canada. In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona, from the 16th to the early 18th century Canada referred to the part of New France that lay along the St. Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named The Canadas, until their union as the British Province of Canada in 1841. Upon Confederation in 1867, Canada was adopted as the name for the new country at the London Conference. The transition away from the use of Dominion was formally reflected in 1982 with the passage of the Canada Act, later that year, the name of national holiday was changed from Dominion Day to Canada Day
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United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
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South America
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South America is a continent located in the western hemisphere, mostly in the southern hemisphere, with a relatively small portion in the northern hemisphere. It may also be considered a subcontinent of the Americas, which is the used in nations that speak Romance languages. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean, North America and it includes twelve sovereign states, a part of France, and a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands, Trinidad and Tobago, South America has an area of 17,840,000 square kilometers. Its population as of 2005 has been estimated at more than 371,090,000, South America ranks fourth in area and fifth in population. Brazil is by far the most populous South American country, with more than half of the population, followed by Colombia, Argentina, Venezuela. In recent decades Brazil has also concentrated half of the regions GDP and has become a first regional power, most of the population lives near the continents western or eastern coasts while the interior and the far south are sparsely populated. Most of the continent lies in the tropics, the continents cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the majority of South Americans speak Portuguese or Spanish. South America occupies the portion of the Americas. The continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border. Almost all of mainland South America sits on the South American Plate, South Americas major mineral resources are gold, silver, copper, iron ore, tin, and petroleum. These resources found in South America have brought high income to its countries especially in times of war or of rapid growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity often has hindered the development of diversified economies and this is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth, South America is home to many interesting and unique species of animals including the llama, anaconda, piranha, jaguar, vicuña, and tapir. The Amazon rainforests possess high biodiversity, containing a proportion of the Earths species. Brazil is the largest country in South America, encompassing around half of the land area
34.
Mexico
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Mexico, officially the United Mexican States, is a federal republic in the southern half of North America. It is bordered to the north by the United States, to the south and west by the Pacific Ocean, to the southeast by Guatemala, Belize, and the Caribbean Sea, and to the east by the Gulf of Mexico. Covering almost two million square kilometers, Mexico is the sixth largest country in the Americas by total area, Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana, pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its base in Mexico-Tenochtitlan, Three centuries later, this territory became Mexico following recognition in 1821 after the colonys Mexican War of Independence. The tumultuous post-independence period was characterized by instability and many political changes. The Mexican–American War led to the cession of the extensive northern borderlands, one-third of its territory. The Pastry War, the Franco-Mexican War, a civil war, the dictatorship was overthrown in the Mexican Revolution of 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the countrys current political system. Mexico has the fifteenth largest nominal GDP and the eleventh largest by purchasing power parity, the Mexican economy is strongly linked to those of its North American Free Trade Agreement partners, especially the United States. Mexico was the first Latin American member of the Organisation for Economic Co-operation and Development and it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts. By 2050, Mexico could become the fifth or seventh largest economy. The country is considered both a power and middle power, and is often identified as an emerging global power. Due to its culture and history, Mexico ranks first in the Americas. Mexico is a country, ranking fourth in the world by biodiversity. In 2015 it was the 9th most visited country in the world, Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus and the Pacific Alliance. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely, the Valley of Mexico, and its people, the Mexica and this became the future State of Mexico as a division of New Spain prior to independence. It is generally considered to be a toponym for the valley became the primary ethnonym for the Aztec Triple Alliance as a result. After New Spain won independence from Spain, representatives decided to name the new country after its capital and this was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan
35.
Brazil
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Brazil, officially the Federative Republic of Brazil, is the largest country in both South America and Latin America. As the worlds fifth-largest country by area and population, it is the largest country to have Portuguese as an official language. Its Amazon River basin includes a vast tropical forest, home to wildlife, a variety of ecological systems. This unique environmental heritage makes Brazil one of 17 megadiverse countries, Brazil was inhabited by numerous tribal nations prior to the landing in 1500 of explorer Pedro Álvares Cabral, who claimed the area for the Portuguese Empire. Brazil remained a Portuguese colony until 1808, when the capital of the empire was transferred from Lisbon to Rio de Janeiro, in 1815, the colony was elevated to the rank of kingdom upon the formation of the United Kingdom of Portugal, Brazil and the Algarves. Independence was achieved in 1822 with the creation of the Empire of Brazil, a state governed under a constitutional monarchy. The ratification of the first constitution in 1824 led to the formation of a bicameral legislature, the country became a presidential republic in 1889 following a military coup détat. An authoritarian military junta came to power in 1964 and ruled until 1985, Brazils current constitution, formulated in 1988, defines it as a democratic federal republic. The federation is composed of the union of the Federal District, the 26 states, Brazils economy is the worlds ninth-largest by nominal GDP and seventh-largest by GDP as of 2015. A member of the BRICS group, Brazil until 2010 had one of the worlds fastest growing economies, with its economic reforms giving the country new international recognition. Brazils national development bank plays an important role for the economic growth. Brazil is a member of the United Nations, the G20, BRICS, Unasul, Mercosul, Organization of American States, Organization of Ibero-American States, CPLP. Brazil is a power in Latin America and a middle power in international affairs. One of the worlds major breadbaskets, Brazil has been the largest producer of coffee for the last 150 years and it is likely that the word Brazil comes from the Portuguese word for brazilwood, a tree that once grew plentifully along the Brazilian coast. In Portuguese, brazilwood is called pau-brasil, with the word brasil commonly given the etymology red like an ember, formed from Latin brasa and the suffix -il. As brazilwood produces a red dye, it was highly valued by the European cloth industry and was the earliest commercially exploited product from Brazil. The popular appellation eclipsed and eventually supplanted the official Portuguese name, early sailors sometimes also called it the Land of Parrots. In the Guarani language, a language of Paraguay, Brazil is called Pindorama
36.
Echimyidae
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The family Echimyidae contains the Neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents and it is probably also the most ecologically diverse, with members ranging from fully arboreal to terrestrial to fossorial habits. They presently exist mainly in South America, three members of the family also range into Central America, species of the extinct subfamily Heteropsomyinae formerly lived on Cuba, Hispaniola, and Puerto Rico in the Antilles, probably until the arrival of Europeans. Some authorities consider the nutria from southern and central South America to be a part of this family, in general form, most spiny rats resemble rats, although they are more closely related to guinea pigs and chinchillas. Most species have stiff, pointed hairs, or spines, that serve for protection from predators. Many echimyids can break off their tails when attacked and this action may confuse predators long enough for the spiny rat to escape. Unlike the tails of some species of lizards, however, the tails of spiny rats do not regenerate, therefore, the tactic cannot be used more than once in each individuals lifetime. Most spiny rats are rare and poorly known, but a few are extremely abundant, various species are respectively terrestrial, arboreal, or fossorial. In general, the forms are most rat-like in appearance, whilst the burrowing species are more gopher-like, with stocky bodies. Most species do poorly in conditions of heat and aridity and are restricted to regions with abundant water. The bristle-spined rat, Chaetomys subspinosus, has sometimes been classified in Echimyidae, the classification with Echimyidae is supported by similarities in the cheek teeth structure. Some of these characters have been, however, reinterpreted as evidence for affinities between Chaetomys and the Erethizontidae. H, a Revision of the Genera of Arboreal Echimyidae, With Descriptions of Two New Genera. Mammalian Diversification, From Chromosomes to Phylogeography, university of California Publications in Zoology. Walkers Mammals of the World, Vol.2
37.
Phylogeny
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The taxa joined together in the tree are implied to have descended from a common ancestor. Phylogenetic trees are central to the field of phylogenetics, each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed, Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetic comparative methods. Unrooted trees illustrate only the relatedness of the nodes and do not require the ancestral root to be known or inferred. The idea of a tree of life arose from ancient notions of a progression from lower to higher forms of life. Charles Darwin also produced one of the first illustrations and crucially popularized the notion of a tree in his seminal book The Origin of Species. Over time, species classification has become static and more dynamic. A rooted phylogenetic tree is a tree with a unique node corresponding to the most recent common ancestor of all the entities at the leaves of the tree. The most common method for rooting trees is the use of an uncontroversial outgroup—close enough to allow inference from trait data or molecular sequencing, unrooted trees illustrate the relatedness of the leaf nodes without making assumptions about ancestry. They do not require the ancestral root to be known or inferred, unrooted trees can always be generated from rooted ones by simply omitting the root. By contrast, inferring the root of an unrooted tree requires some means of identifying ancestry, both rooted and unrooted phylogenetic trees can be either bifurcating or multifurcating, and either labeled or unlabeled. In contrast, a rooted multifurcating tree may have more than two children at some nodes and an unrooted multifurcating tree may have more than three neighbors at some nodes. A labeled tree has specific values assigned to its leaves, while a tree, sometimes called a tree shape. The last distinction is the most biologically relevant, it arises because there are places on an unrooted tree to put the root. For labeled bifurcating trees, there are,2 n −2. for n ≥2 total rooted trees and. 2 n −3. for n ≥3 total unrooted trees, among labeled bifurcating trees, the number of unrooted trees with n leaves is equal to the number of rooted trees with n −1 leaves. A dendrogram is a term for the diagrammatic representation of a phylogenetic tree. A cladogram is a phylogenetic tree formed using cladistic methods and this type of tree only represents a branching pattern, i. e. its branch spans do not represent time or relative amount of character change
38.
Mitochondrion
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The mitochondrion is a double membrane-bound organelle found in all eukaryotic organisms. Some cells in multicellular organisms may however lack them. A number of organisms, such as microsporidia, parabasalids. To date, only one eukaryote, Monocercomonoides, is known to have completely lost its mitochondria, the word mitochondrion comes from the Greek μίτος, mitos, thread, and χονδρίον, chondrion, granule or grain-like. Mitochondria generate most of the supply of adenosine triphosphate, used as a source of chemical energy. Mitochondria are commonly between 0.75 and 3 μm in diameter but vary considerably in size and structure, unless specifically stained, they are not visible. Mitochondrial biogenesis is in turn temporally coordinated with these cellular processes, Mitochondria have been implicated in several human diseases, including mitochondrial disorders, cardiac dysfunction, heart failure and autism. The number of mitochondria in a cell can vary widely by organism, tissue, for instance, red blood cells have no mitochondria, whereas liver cells can have more than 2000, The organelle is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, the space, the inner membrane. Although most of a cells DNA is contained in the cell nucleus, mitochondrial proteins vary depending on the tissue and the species. In humans,615 distinct types of protein have been identified from cardiac mitochondria, the mitochondrial proteome is thought to be dynamically regulated. The first observations of structures that probably represented mitochondria were published in the 1840s. Richard Altmann, in 1890, established them as cell organelles, the term mitochondria was coined by Carl Benda in 1898. Leonor Michaelis discovered that Janus green can be used as a stain for mitochondria in 1900. Benjamin F. Kingsbury, in 1912, first related them with cell respiration, in 1913, particles from extracts of guinea-pig liver were linked to respiration by Otto Heinrich Warburg, which he called grana. Warburg and Heinrich Otto Wieland, who had postulated a similar particle mechanism. It was not until 1925, when David Keilin discovered cytochromes, in the following years, the mechanism behind cellular respiration was further elaborated, although its link to the mitochondria was not known. The introduction of tissue fractionation by Albert Claude allowed mitochondria to be isolated from other cell fractions, in 1946, he concluded that cytochrome oxidase and other enzymes responsible for the respiratory chain were isolated to the mitchondria
39.
Cytochrome b
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Cytochrome b is a protein found in the mitochondria of eukaryotic cells. It functions as part of the transport chain and is the main subunit of transmembrane cytochrome bc1. In the mitochondrion of eukaryotes and in prokaryotes, cytochrome b is a component of respiratory chain complex III — also known as the bc1 complex or ubiquinol-cytochrome c reductase. In plant chloroplasts and cyanobacteria, there is a protein, cytochrome b6. These complexes are involved in transport, the pumping of protons to create a proton-motive force. This proton gradient is used for the generation of ATP and these complexes play a vital role in cells. Cytochrome b/b6 is a membrane protein of approximately 400 amino acid residues that probably has 8 transmembrane segments. In plants and cyanobacteria, cytochrome b6 consists of two subunits encoded by the petB and petD genes, cytochrome b/b6 non-covalently binds two heme groups, known as b562 and b566. Four conserved histidine residues are postulated to be the ligands of the atoms of these two heme groups. Cytochrome b is used as a region of mitochondrial DNA for determining phylogenetic relationships between organisms, due to its sequence variability. It is considered to be most useful in determining relationships within families, mutations in cytochrome b primarily result in exercise intolerance in human patients, though more rare, severe multi-system pathologies have also been reported. Single-point mutations in cytochrome b of Plasmodium falciparum and P. berghei are associated with resistance to the anti-malarial drug atovaquone
40.
Karyology
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A karyotype is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is used for the complete set of chromosomes in a species or in an individual organism. Karyotypes describe the chromosome count of an organism and what these chromosomes look like under a light microscope, attention is paid to their length, the position of the centromeres, banding pattern, any differences between the sex chromosomes, and any other physical characteristics. The preparation and study of karyotypes is part of cytogenetics, the study of whole sets of chromosomes is sometimes known as karyology. The chromosomes are depicted in a format known as a karyogram or idiogram, in pairs, ordered by size. The basic number of chromosomes in the cells of an individual or a species is called the somatic number and is designated 2n. In the germ-line the chromosome number is n. p28 Thus, so, in normal diploid organisms, autosomal chromosomes are present in two copies. There may, or may not, be sex chromosomes, polyploid cells have multiple copies of chromosomes and haploid cells have single copies. The study of karyotypes is important for cell biology and genetics, Karyotypes can be used for many purposes, such as to study chromosomal aberrations, cellular function, taxonomic relationships, and to gather information about past evolutionary events. Chromosomes were first observed in plant cells by Carl Wilhelm von Nägeli in 1842 and their behavior in animal cells was described by Walther Flemming, the discoverer of mitosis, in 1882. The name was coined by another German anatomist, Heinrich von Waldeyer in 1888 and it is New Latin from Ancient Greek κάρυον karyon, kernel, seed, or nucleus, and τύπος typos, general form). The next stage took place after the development of genetics in the early 20th century, lev Delaunay seems to have been the first person to define the karyotype as the phenotypic appearance of the somatic chromosomes, in contrast to their genic contents. The subsequent history of the concept can be followed in the works of C. D. Darlington, investigation into the human karyotype took many years to settle the most basic question, how many chromosomes does a normal diploid human cell contain. In 1912, Hans von Winiwarter reported 47 chromosomes in spermatogonia and 48 in oogonia, concluding an XX/XO sex determination mechanism. Painter in 1922 was not certain whether the diploid of humans was 46 or 48, at first favouring 46, but revised his opinion from 46 to 48, considering the techniques of the time, these results were remarkable. In textbooks, the number of human chromosomes remained at 48 for over thirty years, New techniques were needed to correct this error. The work took place in 1955, and was published in 1956, the karyotype of humans includes only 46 chromosomes. Rather interestingly, the apes have 48 chromosomes
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Erethizontidae
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The New World porcupines, family Erethizontidae, are large arboreal rodents, distinguished by their spiny coverings from which they take their name. They inhabit forests and wooded regions across North America, and into northern South America, although both the New World and Old World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related. New World porcupines are stout animals, with blunt, rounded heads, fleshy, mobile snouts, the spines are mixed with long, soft hairs. They are distinguished from the Old World porcupines in that they have rooted molars, complete collar bones, entire upper lips, tuberculated soles, no trace of first front toes, and four teats. They are less strictly nocturnal than Old World species in their habits and their long and powerful prehensile tails help them balance when they are in the tree tops. Their diets consist mainly of bark, leaves, and conifer needles, but can also include roots, stems, berries, fruits, seeds, nuts, grasses, some species also eat insects and small reptiles. Their teeth are similar to those of Old World porcupines, with the dental formula 1.0.1.31.0.1.3 Solitary offspring are born after a period of up to 210 days. The young are fully developed, with open eyes, and are able to climb trees within a few days of birth. It is a native of the part of Canada and the United States. The tree porcupines contain 16 species and they are found throughout tropical South America, with two extending into Mexico. They are of a lighter build than the ground porcupines, with short, close, many-coloured spines, often mixed with hairs and these three genera are often united into a single genus Coendou. Genus Chaetomys, distinguished by the shape of its skull and the complexity of its teeth, contains C. subspinosus. This animal is considered a member of Echimyidae on the basis of its premolars
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Erethizontinae
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Porcupines are rodentian mammals with a coat of sharp spines, or quills, that protect against predators. The term covers two families of animals, the Old World porcupines of family Hystricidae, and the New World porcupines of family Erethizontidae, the Old World porcupines live in southern Europe, Asia, and most of Africa. They are large, terrestrial, and strictly nocturnal, in taxonomic terms, they form the family Hystricidae. The New World porcupines are indigenous to North America and northern South America and they live in wooded areas and can climb trees, where some species spend their entire lives. They are less strictly nocturnal than their Old World relatives, in taxonomic terms, they form the family Erethizontidae. Porcupines are the third-largest of the rodents, behind the capybara, most porcupines are about 60–90 cm long, with an 20–25 cm long tail. Weighing 5–16 kg, they are rounded, large, and slow, Porcupines occur in various shades of brown, gray, and white. Porcupines spiny protection resembles that of the unrelated erinaceomorph hedgehogs and Australian spiny anteaters or monotreme echidnas, the name porcupine comes from Latin porcus pig + spina spine, quill, via Old Italian—Middle French—Middle English. A regional American name for the animal is quill pig, similarly, the German name, Stachelschwein, means thorn-swine and the Afrikaans name, ystervark, means iron pig. Fossils belonging to the Hystrix genus date back to the late Miocene of Africa, a porcupine is any of 29 species of rodents belonging to the families Erethizontidae or Hystricidae. The two families of porcupines are quite different, and although both belong to the Hystricognathi branch of the vast order Rodentia, they are not closely related, the 11 Old World porcupines tend to be fairly large, and have spikes grouped in clusters. The two subfamilies of New World porcupines are mostly smaller, have their quills attached singly rather than grouped in clusters, the New World porcupines evolved their spines independently and are more closely related to several other families of rodents than they are to the Old World porcupines. The North American porcupine is a herbivore, it leaves, herbs, twigs. In the winter, it may eat bark and it often climbs trees to find food. The African porcupine is not a climber and forages on the ground and it is mostly nocturnal, but will sometimes forage for food in the day. Porcupines have become a pest in Kenya and are eaten as a delicacy, Porcupines quills, or spines, take on various forms, depending on the species, but all are modified hairs coated with thick plates of keratin, and embedded in the skin musculature. Old World porcupines have quills embedded in clusters, whereas in New World porcupines, single quills are interspersed with bristles, underfur, quills are released by contact or may drop out when the porcupine shakes its body. New quills grow to replace lost ones, Porcupines were long believed to have the ability to project their quills to a considerable distance at an enemy, but this has since been proven to be untrue
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Bicolored-spined porcupine
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The bicolored-spined porcupine is a species of nocturnal and arboreal rodent in the family Erethizontidae. It is found in Bolivia, Colombia, Ecuador, and Peru, the head and body of Coendou bicolor measure about 543 mm, and another 481 mm is tail. The body is covered with spines, pale yellow at the base and black-tipped. The bicolored-spined porcupine has a prehensile tail that is primarily free of spines. Mammals of the Neotropics, volume 1 - The Northern Neotropics, university of Chicago Press, Chicago IL
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Streaked dwarf porcupine
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The streaked dwarf porcupine, Coendou ichillus, is a porcupine species in the family Erethizontidae. It is known from the lowlands of eastern Ecuador, and may be present in Peru as well and it appears to be nocturnal and arboreal in its habits. This species was sometimes assigned to Sphiggurus, a genus no longer recognized since genetic studies showed it to be polyphyletic. Its closest relatives are the frosted hairy dwarf porcupine and the brown hairy dwarf porcupine
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Mexican hairy dwarf porcupine
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The Mexican hairy dwarf porcupine or Mexican tree porcupine is a species of rodent in the family Erethizontidae. It is found in Costa Rica, El Salvador, Guatemala, Honduras, Panama, Mexico, Nicaragua and this species was formerly sometimes assigned to Sphiggurus, a genus no longer recognized since genetic studies showed it to be polyphyletic. Its closest relatives are the Andean porcupine and the stump-tailed porcupine and this porcupine has a pale head and a dark-coloured body. The head-and-body length ranges between about 320 and 457 mm, with a tail ranging from 200 to 358 mm, the maximum weight is about 2.6 kg. This porcupine is covered with yellowish spines but these are almost entirely obscured by the long black hair on the body. Sometimes the spines on the shoulders and back are visible projecting through the hairs, by contrast, the head is hairless, revealing the yellowish spines, the snout is pink, broad and bulbous, and the eyes are small. The tail is prehensile, spiny and broad at the base and this porcupine differs from Rothschilds porcupine in that Rothschilds is more obviously spiny and lacks the hairy coat. An arboreal species, it uses its tail to hold onto branches. It is nocturnal and is more active on dark nights. The day is spent in a tree, concealed on a leafy branch, or in highland areas. As it uses the same hiding place each day, a pile of droppings accumulates which produces a strong odour, the diet consists of buds, young leaves, fruits and seeds. It particularly favours fruiting trees such as Inga, Cecropia, Ficus, individuals normally live alone and are silent, but in the breeding season it is more vocal, emitting screams and yowls. The female usually bears a single offspring
