1.
Megaannum
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A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earths axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the globe, four seasons are recognized, spring, summer, autumn. In tropical and subtropical regions several geographical sectors do not present defined seasons, but in the seasonal tropics, a calendar year is an approximation of the number of days of the Earths orbital period as counted in a given calendar. The Gregorian, or modern, calendar, presents its calendar year to be either a common year of 365 days or a year of 366 days, as do the Julian calendars. For the Gregorian calendar the average length of the year across the complete leap cycle of 400 years is 365.2425 days. The ISO standard ISO 80000-3, Annex C, supports the symbol a to represent a year of either 365 or 366 days, in English, the abbreviations y and yr are commonly used. In astronomy, the Julian year is a unit of time, it is defined as 365.25 days of exactly 86400 seconds, totalling exactly 31557600 seconds in the Julian astronomical year. The word year is used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year. Similarly, year can mean the period of any planet, for example. The term can also be used in reference to any long period or cycle, west Saxon ġēar, Anglian ġēr continues Proto-Germanic *jǣran. Cognates are German Jahr, Old High German jār, Old Norse ár and Gothic jer, all the descendants of the Proto-Indo-European noun *yeh₁rom year, season. Cognates also descended from the same Proto-Indo-European noun are Avestan yārǝ year, Greek ὥρα year, season, period of time, Old Church Slavonic jarŭ, Latin annus is from a PIE noun *h₂et-no-, which also yielded Gothic aþn year. Both *yeh₁-ro- and *h₂et-no- are based on verbal roots expressing movement, *h₁ey- and *h₂et- respectively, the Greek word for year, ἔτος, is cognate with Latin vetus old, from the PIE word *wetos- year, also preserved in this meaning in Sanskrit vat-sa- yearling and vat-sa-ras year. Derived from Latin annus are a number of English words, such as annual, annuity, anniversary, etc. per annum means each year, anno Domini means in the year of the Lord. No astronomical year has an number of days or lunar months. Financial and scientific calculations often use a 365-day calendar to simplify daily rates, in the Julian calendar, the average length of a year is 365.25 days. In a non-leap year, there are 365 days, in a year there are 366 days
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
Paleogene
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The Paleogene is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago to the beginning of the Neogene Period 23.03 Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon and this period consists of the Paleocene, Eocene and Oligocene epochs. The terms Paleogene System and lower Tertiary System are applied to the rocks deposited during the Paleogene Period. By dividing the Tertiary Period into two periods instead of directly into five epochs, the periods are more comparable to the duration of periods of the preceding Mesozoic and Paleozoic Eras. The trend was caused by the formation of the Antarctic Circumpolar Current. During the Paleogene, the continued to drift closer to their current positions. India was in the process of colliding with Asia, subsequently forming the Himalayas, the Atlantic Ocean continued to widen by a few centimeters each year. Africa was moving north to meet with Europe and form the Mediterranean, inland seas retreated from North America early in the period. Australia had also separated from Antarctica and was drifting towards Southeast Asia, mammals began a rapid diversification during this period. Some of these mammals would evolve into forms that would dominate the land, while others would become capable of living in marine, specialized terrestrial. Those that took to the oceans became modern cetaceans, while those that took to the trees became primates, the group to which humans belong. Birds, which were well established by the end of the Cretaceous. In comparison to birds and mammals, most other branches of life remained unchanged during this period. As the Earth cooled, tropical plants became less numerous and were now restricted to equatorial regions, deciduous plants, which could survive through the seasonal climates the world was now experiencing, became more common. The Paleogene is notable in the context of offshore oil drilling, and especially in Gulf of Mexico oil exploration and these rock formations represent the current cutting edge of deep-water oil discovery. Lower Tertiary explorations to date include, Kaskida Oil Field Tiber Oil Field Jack 2 Paleogene Microfossils, 180+ images of Foraminifera
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Neogene
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The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene, some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. During this period, mammals and birds continued to evolve into modern forms. Early hominids, the ancestors of humans, appeared in Africa near the end of the period, some continental movement took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the ocean currents from the Pacific to the Atlantic ocean. The global climate cooled considerably over the course of the Neogene, the terms Neogene System and upper Tertiary System describe the rocks deposited during the Neogene Period. The continents in the Neogene were very close to their current positions, the Isthmus of Panama formed, connecting North and South America. The Indian subcontinent continued to collide with Asia, forming the Himalayas, sea levels fell, creating land bridges between Africa and Eurasia and between Eurasia and North America. The global climate became seasonal and continued an overall drying and cooling trend which began at the start of the Paleogene. The ice caps on both poles began to grow and thicken, and by the end of the period the first of a series of glaciations of the current Ice Age began, marine and continental flora and fauna have a modern appearance. The reptile group Choristodera became extinct in the part of the period. Mammals and birds continued to be the dominant terrestrial vertebrates, the first hominids, the ancestors of humans, appeared in Africa and spread into Eurasia. In response to the cooler, seasonal climate, tropical plant species gave way to deciduous ones, grasses therefore greatly diversified, and herbivorous mammals evolved alongside it, creating the many grazing animals of today such as horses, antelope, and bison. The Neogene traditionally ended at the end of the Pliocene Epoch, just before the definition of the beginning of the Quaternary Period. However, there was a movement amongst geologists to also include ongoing geological time in the Neogene, by dividing the Cenozoic Era into three periods instead of seven epochs, the periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic eras. The International Commission on Stratigraphy once proposed that the Quaternary be considered a sub-era of the Neogene, with a date of 2.58 Ma. In the 2004 proposal of the ICS, the Neogene would have consisted of the Miocene and Pliocene epochs, thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya. Digital Atlas of Neogene Life for the Southeastern United States — by San Jose State University via Web Archive
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Holocene
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The Holocene is the geological epoch that began after the Pleistocene at approximately 11,700 years before present. The term Recent has often used as an exact synonym of Holocene. The Holocene is part of the Quaternary period and its name comes from the Ancient Greek words ὅλος and καινός, meaning entirely recent. It has been identified with the current warm period, known as MIS1, given these, a new term, Anthropocene, is specifically proposed and used informally only for the very latest part of modern history involving significant human impact. It is accepted by the International Commission on Stratigraphy that the Holocene started approximately 11,700 years ago, the epoch follows the Pleistocene and the last glacial period. The Holocene can be subdivided into five time intervals, or chronozones, based on climatic fluctuations, Preboreal, Boreal, Atlantic, Subboreal and they find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest. The scheme was defined for Northern Europe, but the changes were claimed to occur more widely. The periods of the include a few of the final pre-Holocene oscillations of the last glacial period. Paleontologists have not defined any faunal stages for the Holocene, if subdivision is necessary, periods of human technological development, such as the Mesolithic, Neolithic, and Bronze Age, are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world, climatically, the Holocene may be divided evenly into the Hypsithermal and Neoglacial periods, the boundary coincides with the start of the Bronze Age in Europe. According to some scholars, a division, the Anthropocene, has now begun. Continental motions due to plate tectonics are less than a kilometre over a span of only 10,000 years, however, ice melt caused world sea levels to rise about 35 m in the early part of the Holocene. The sea level rise and temporary land depression allowed temporary marine incursions into areas that are now far from the sea, Holocene marine fossils are known, for example, from Vermont and Michigan. Other than higher-latitude temporary marine incursions associated with depression, Holocene fossils are found primarily in lakebed, floodplain. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during the period exceeds any likely tectonic uplift of non-glacial origin, post-glacial rebound in the Scandinavia region resulted in the formation of the Baltic Sea. The region continues to rise, still causing weak earthquakes across Northern Europe, the equivalent event in North America was the rebound of Hudson Bay, as it shrank from its larger, immediate post-glacial Tyrrell Sea phase, to near its present boundaries. Climate has been stable over the Holocene. It appears that this was influenced by the glacial ice remaining in the Northern Hemisphere until the later date
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Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
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Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
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Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
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Actinopterygii
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Actinopterygii /ˌæktᵻnˌɒptəˈrɪdʒi. aɪ/, or the ray-finned fishes, constitute a class or subclass of the bony fishes. These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm, to the ocean sunfish, at 2,300 kg. Ray-finned fishes occur in variant forms. The main features of a typical ray-finned fish are shown in the diagram at the left. In nearly all ray-finned fish, the sexes are separate, development then proceeds with a free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism, in most cases this involves protogyny, fish starting life as females and converting to males at some stage, triggered by some internal or external factor. This may be advantageous as females become less prolific as they age while male fecundity increases with age, protandry, where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization, of the oviparous teleosts, most do not provide parental care. Viviparity is relatively rare and is found in about 6% of teleost species, male territoriality preadapts a species for evolving male parental care. There are a few examples of fish that self-fertilise, the mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to the habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C and can fertilise eggs that are spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred, the earliest known fossil actinopterygiian is Andreolepis hedei, dating back 420 million years. Remains have been found in Russia, Sweden, and Estonia, actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii, in turn, are divided into the infraclasses Holostei and Teleostei, during the Mesozoic and Cenozoic the teleosts in particular diversified widely, and as a result, 96% of all known fish species are teleosts. The cladogram shows the groups of actinopterygians and their relationship to the terrestrial vertebrates that evolved from a related group of fish
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Pieter Bleeker
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Pieter Bleeker was a Dutch medical doctor, ichthyologist, and herpetologist. He was famous for the Atlas Ichthyologique des Orientales Neerlandaises, his work on the fishes of East Asia published between 1862 and 1877. Bleeker was employed as a officer in the Royal Netherlands East Indies Army from 1842 to 1860. During that time, he did most of his ichthyology work and he acquired many of his specimens from local fishermen, but he also built up an extended network of contacts who would send him specimens from various government outposts throughout the islands. During his time in Indonesia, he collected well over 12,000 specimens, Bleeker corresponded with Auguste Duméril of Paris. His work in ichthyology and tropical medicine was recognised by two doctorates honoris causa and it was published in 36 volumes between 1862 and his death in 1878. Between 1977 and 1983, the Smithsonian republished the work in 10 volumes, Bleeker published more than 500 papers on ichthyology, describing 511 new genera and 1,925 new species. He also worked in herpetology, describing at least 14 species of reptiles, in 1855, he became correspondent of the Royal Netherlands Academy of Arts and Sciences, department Natuurkunde, and in 1862 a member. In 1856 he was elected correspondent for the Muséum national dhistoire naturelle in Paris, in January 1864 he received a French knighthood of the Légion dhonneur. He was president of the Royal Netherlands Institute of Southeast Asian and Caribbean Studies, beolens B, Watkins M, Grayson M.2011. Xiii +296 pp. ISBN 978-1-4214-0135-5, P. Bleeker, Levensbericht in, Jaarboek,1877, Amsterdam, pp. 5-159 Bleeker, P, van Oijen, MJP, Loots, GMP, van Limburg, FJG. A precursor of the fish of the Indian Archipelago, the Bleeker/Günther letters and the sale of Bleeker specimens to the British Museum. Whitehead, PJP, Boeseman, M, Wheeler, AC, the types of Bleekers Indo-Pacific Elopoid and Clupeoid Fishes
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Type species
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A similar concept is used for suprageneric groups called a type genus. In botanical nomenclature, these terms have no standing under the code of nomenclature. In botany, the type of a name is a specimen which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name, names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. In bacteriology, a species is assigned for each genus. Every named genus or subgenus in zoology, whether or not currently recognized as valid, is associated with a type species. In practice, however, there is a backlog of untypified names defined in older publications when it was not required to specify a type, a type species is both a concept and a practical system that is used in the classification and nomenclature of animals. The type species represents the species and thus definition for a particular genus name. In the Glossary, type species is defined as The nominal species that is the type of a nominal genus or subgenus. The type species permanently attaches a formal name to a genus by providing just one species within that genus to which the name is permanently linked. The species name in turn is fixed, in theory, to a type specimen, for example, the type species for the land snail genus Monacha is Monacha cartusiana. That genus is placed within the family Hygromiidae. The type genus for that family is the genus Hygromia, the concept of the type species in zoology was introduced by Pierre André Latreille. The International Code of Zoological Nomenclature states that the name of the type species should always be cited. It gives an example in Article 67.1, Astacus marinus Fabricius,1775 was later designated as the type species of the genus Homarus, thus giving it the name Homarus marinus. However, the species of Homarus should always be cited using its original name. 3, the type of the genus name Elodes is quoted as the type of the species name Hypericum aegypticum, Glossary of scientific naming Genetypes – genetic sequence data from type specimens. Holotype Paratype Principle of Typification Type Type genus
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European perch
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The species is a popular quarry for anglers, and has been widely introduced beyond its native area, into Australia, New Zealand, and South Africa. They have caused damage to native fish populations in Australia and have been proclaimed a noxious species in New South Wales. European perch are greenish with red pelvic, anal and caudal fins and they have five to eight dark vertical bars on their sides. When the perch grow larger, a hump grows between its head and dorsal fin, European perch can vary greatly in size between bodies of water. They can live for up to 22 years, and older perch are often larger than average. The British record is 2.8 kg, but they grow larger in mainland Europe than in Britain. As of May 2016, the official all tackle world record recognised by the International Game Fish Association stands at 2.9 kg for a Finnish fish caught September 4,2010. In January 2010 a perch with a weight of 3.75 kg has been caught in the River Meuse, due to the low salinity levels of the Baltic Sea, especially around the Finnish archipelago and Bothnian Sea, many freshwater fish live and thrive there. Perch especially are in abundance and grow to a considerable size due to the diet of Baltic herring, the range of the European perch covers fresh water basins all over Europe, excluding the Iberian peninsula. Their range is known to reach the Kolyma River in Siberia to the east and it is also common in some of the brackish waters of the Baltic Sea. European perch has been introduced, with reported adverse ecological impact after introduction. The European perch lives in slow-flowing rivers, deep lakes and ponds and it tends to avoid cold or fast-flowing waters but some specimens penetrate waters of these type, although they do not breed in this habitat. Perch often start eating other fish when it reaches size of 120 mm. Male perch is mature to reproduce in the age of 1–2 years, female in age of 2–4 years. The perch spawns between February and July, depositing the eggs upon water plants, or the branches of trees or shrubs that have become immersed in the water. There has been speculation, but only evidence, that eggs have been to stick to the legs of wading birds. The first scientific description of the perch was made by Peter Artedi in 1730. He defined the basic signs of this species after studying perch from Swedish lakes. Artedi described its features, counting the fin rays scales and vertebrae of the typical perch, in 1758, Carl Linnaeus named it Perca fluviatilis
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Carl Linnaeus
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Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands and he then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist. Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is also considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
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10th edition of Systema Naturae
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The 10th edition of Systema Naturae is a book written by Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature. In it, Linnaeus introduced binomial nomenclature for animals, something he had already done for plants in his 1753 publication of Species Plantarum, before 1758, most biological catalogues had used polynomial names for the taxa included, including earlier editions of Systema Naturae. The first work to consistently apply binomial nomenclature across the kingdom was the 10th edition of Systema Naturae. Names published before that date are unavailable, even if they would otherwise satisfy the rules, during Linnaeus lifetime, Systema Naturae was under continuous revision. The Animal Kingdom, Animals enjoy sensation by means of an organization, animated by a medullary substance, perception by nerves. They have members for the different purposes of life, organs for their different senses and they all originate from an egg. Their external and internal structure, their anatomy, habits, instincts. The list has been broken down into the six classes Linnaeus described for animals, Mammalia, Aves, Amphibia, Pisces, Insecta. These classes were created by studying the internal anatomy, as seen in his key. Warm, red blood Viviparous, Mammalia Oviparous, Aves Heart with 1 auricle,1 ventricle, cold, red blood Lungs voluntary, Amphibia External gills, Pisces Heart with 1 auricle,0 ventricles. Linnaeus described mammals as, Animals that suckle their young by means of lactiferous teats, in external and internal structure they resemble man, most of them are quadrupeds, and with man, their natural enemy, inhabit the surface of the Earth. The largest, though fewest in number, inhabit the ocean and they are areal, vocal, swift and light, and destitute of external ears, lips, teeth, scrotum, womb, bladder, epiglottis, corpus callosum and its arch, and diaphragm. They breathe by means of gills, which are united by a bony arch, swim by means of radiate fins. Many of them are without a head, and most of them without feet. They are principally distinguished by their tentacles, by the Ancients they were not improperly called imperfect animals, as being destitute of ears, nose, head, eyes and legs, and are therefore totally distinct from Insects. In addition to repeating the species he had listed in his Species Plantarum. The species from Species Plantarum were numbered sequentially, while the new species were labelled with letters, new plant species described in the 10th edition of Systema Naturae include, The original 1758 Systema Naturae Linnaeus 1758 Classification of Animals on the Taxonomicon
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Vertebrate
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Vertebrates /ˈvɜːrtᵻbrᵻts/ comprise all species of animals within the subphylum Vertebrata /-ɑː/. Vertebrates represent the majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the fish and the jawed vertebrates, which include the cartilaginous fish. A bony fish known as the lobe-finned fishes is included with tetrapods, which are further divided into amphibians, reptiles, mammals. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, vertebrates make up less than five percent of all described animal species, the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as Craniata when discussing morphology, molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a group of vertebrates in the common taxon of craniata. The word origin of vertebrate derives from the Latin word vertebratus, the Proto-Indo-European language origins are still unclear. Vertebrate is derived from the vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic body plan, a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it. In all vertebrates, the mouth is found at, or right below, the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon, jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills, the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch, the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their relatives have more than 50 pairs of gills. In amphibians and some primitive fishes, the larvae bear external gills. These are reduced in adulthood, their function taken over by the gills proper in fishes, some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish apparently being irrevocably lost very early in the evolution of tetrapods
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Osteichthyes
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Osteichthyes /ˌɒstiːˈɪkθi. iːz/, popularly referred to as the bony fish, is a diverse taxonomic group of fish that have skeletons primarily composed of bone tissue, as opposed to cartilage. The vast majority of fish are members of Osteichthyes, which is a diverse and abundant group consisting of 45 orders. It is the largest class of vertebrates in existence today, the group Osteichthyes is divided into the ray-finned fish and lobe-finned fish. The oldest known fossils of fish are about 420 million years ago. Osteichthyes can be compared to Euteleostomi, in paleontology, the terms are synonymous. However, recently published phylogenetic trees treat the Osteichthyes as a clade, bony fish are characterized by a relatively stable pattern of cranial bones, rooted, medial insertion of mandibular muscle in the lower jaw. The head and pectoral girdles are covered with large dermal bones, the eyeball is supported by a sclerotic ring of four small bones, but this characteristic has been lost or modified in many modern species. The labyrinth in the ear contains large otoliths. The braincase, or neurocranium, is divided into anterior and posterior sections divided by a fissure. Early bony fish had simple lungs which helped them breathe in low-oxygen water, in many bony fish these have evolved into swim bladders, which help the body create a neutral balance between sinking and floating. They do not have fin spines, but instead support the fin with lepidotrichia and they also have an operculum, which helps them breathe without having to swim. Bony fish have no placoid scales, most have smooth and overlapping ganoid, cycloid or ctenoid scales. Traditionally, Osteichthyes is considered a class, recognised on having a swim bladder, under this classification systems, the Osteichthyes are paraphyletic with regard to land vertebrates as the common ancestor of all Osteichthyes includes tetrapods amongst its descendants. The largest subclass, the Actinopterygii are monophyletic, but with the inclusion of the smaller sub-class Sarcopterygii and this has led to an alternative classification, splitting the Osteichthyes into two full classes. Paradoxically, Sarcopterygii is under this scheme monophyletic, as it includes the tetrapods, most bony fish belong to the ray-finned fish. The phylogeny of living bony fishes is shown in the cladogram, for the majority this is their sole or main means of respiration. Lungfish and other species are capable of respiration through lungs or vascularized swim bladders. Other species can respire through their skin, intestines, and/or stomach, Osteichthyes are primitively ectothermic, meaning that their body temperature is dependent on that of the water
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Perch
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Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. Many species of freshwater gamefish more or less resemble perch, in fact, the exclusively saltwater dwelling red drum is often referred to as a red perch, though by definition perch are freshwater fish. Though many fish are referred to as perch as a name, to be considered a true perch. The type species for genus is the European perch, Perca fluviatilis. Most authorities recognize three species within the genus, The European perch is found in Europe and Asia. This species is greenish in color with dark vertical bars on its sides with a red or orange coloring in the tips of its fins. The European perch has been introduced in New Zealand and Australia. In Australia, larger specimens have been bred, but the species grows larger than about six pounds. The Balkhash perch is found in Kazakhstan, Uzbekistan, and China and it is very similar to the European perch, and grows to a comparable size. The yellow perch, smaller and paler than the European perch, is found in the United States, in northern areas, it is sometimes referred to as the lake perch. This species is prized for its quality and has often been raised in hatcheries. Yellow perch are almost identical in appearance to European perch, but have a yellow coloring. These fish typically reach a size of about 15 in and 2.2 lb. The general body type of a perch is somewhat long and rounded, true perch have rough or ctenoid scales. On the anterior side of the head are the maxilla and lower mandible for the mouth, a pair of nostrils, on the posterior sides are the opercula, which protect the gills, and the lateral line system, which is sensitive to vibrations in the water. The kidney of the runs along the backbone and forms a head. Perch have paired pectoral and pelvic fins, and two fins, the first one spiny and the second soft. These two fins can be separate or joined, Perch are carnivorous fish most commonly found in small ponds, lakes, streams, or rivers
27.
Aquatic ecosystem
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An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on other and on their environment live in aquatic ecosystems. The two main types of ecosystems are marine ecosystems and freshwater ecosystems. Marine ecosystems cover approximately 71% of the Earths surface and contain approximately 97% of the planets water and they generate 32% of the worlds net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has a salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems, marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, the benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides, in this figure it is termed the littoral zone, other near-shore zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web, classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations, environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources, marine pollution, climate change, and building on coastal areas. Freshwater ecosystems cover 0. 78% of the Earths surface and inhabit 0. 009% of its total water and they generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the known fish species. There are three types of freshwater ecosystems, Lentic, slow moving water, including pools, ponds. Lotic, faster moving water, for example streams and rivers, wetlands, areas where the soil is saturated or inundated for at least part of the time. Lake ecosystems can be divided into zones, one common system divides lakes into three zones. The first, the zone, is the shallow zone near the shore. This is where rooted wetland plants occur, the offshore is divided into two further zones, an open water zone and a deep water zone
28.
Marlin
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A marlin is a fish from the family Istiophoridae, which includes about 10 species. It has a body, a spear-like snout or bill. Its common name is thought to derive from its resemblance to a sailors marlinspike, even more so than their close relatives, the scombrids, marlins are fast swimmers, reaching speeds of about 80 km/h. They are popular sporting fish in tropical areas, the marlins are perciform fish, most closely related to the swordfish and Scombridae. On the 85th day, Santiago, the old fisherman, hooks a resolute marlin, marlin fishing Sailfish Froese, Rainer, and Daniel Pauly, eds. A compendium of fossil marine animal genera, ghost Fish Revelation May Alter Marlins Status from National Public Radio
29.
Makaira
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The Atlantic blue marlin is a species of marlin endemic to the Atlantic Ocean. The Atlantic blue marlin feeds on a variety of organisms near the surface. It uses its bill to stun, injure, or kill while knifing through a school of fish or other prey, Marlin is a popular game fish. The relatively high fat content of its meat makes it valuable in certain markets. It is the fish of the Commonwealth of the Bahamas and is thus featured on its coat of arms. Blue marlin are distributed throughout the tropical and subtropical waters of the Atlantic, Indian, females can grow up to four times the weight of males. The maximum published weight is 818 kg and length 5 m, adult blue marlin have few predators apart from killer whales, sharks, and humans. They are sought after as a prized game fish by anglers and are taken by commercial fishermen. Blue marlin are currently considered a species by the IUCN due to overfishing. Some other historic English names for the marlin are Cuban black marlin, ocean gar. The blue marlin is placed in the genus Makaira and this name is derived from the Greek word machaira, meaning a short sword or bent dagger, and the Latin machaera, sword. The specific epithet nigricans is Latin for becoming black, the blue marlin is part of the billfish family Istiophoridae and is in the perch-like order Perciformes. In addition, it is in the suborder Xiphioidei and is a member of the subclass Neopterygii and it is also in the class of Actinopterygii, which includes ray-finned fishes and spiny-rayed fishes, and the superclass Osteichthyes, which includes all of the bony fishes. The classification of the Atlantic blue marlin and the Indo-Pacific blue marlin as separate species is under debate. A separate study by V. P. Buonaccorsi, J. R. Mcdowell, the longest females can reach a length of 5 m with the bill, from eye to tip, constituting about 20% of the total body length. Body mass in the largest female specimens has been reported from 540 to 820 kg, depending on the source. The largest blue marlin caught by IGFA angling rules is from Vitoria, Brazil, both sexes have 24 vertebrae, of which 11 are precaudal and 13 are caudal. The marlin has two fins and two anal fins
30.
Percidae
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The Percidae are a family of perciform fish found in fresh and brackish waters of the Northern Hemisphere. The majority are Nearctic, but there are also Palearctic species, the family contains about 200 species in 11 genera. The perches, and their relatives are in family, well-known species include the walleye, sauger, ruffe. However, small fish known as darters are also a part of this family, also, many percid fish have a heart-shaped plate of teeth on the roof of the mouth. The shape of fish is usually somewhat slender and laterally compressed. Their scales are generally harsh and rough to the feel, or ctenoid, percid fish are among the most beautiful of the freshwater fish due to their brilliant colors
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Serranidae
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The Serranidae are a large family of fishes belonging to the order Perciformes. The family contains about 450 species in 65 genera, including the sea basses and the groupers. Although many species are small, in some less than 10 cm. Representatives of this live in tropical and subtropical seas worldwide. Many serranid species are colored, and many of the larger species are caught commercially for food. They are usually found over reefs, in tropical to subtropical waters along the coasts, serranids are generally robust in form, with large mouths and small spines on the gill coverings. They typically have several rows of teeth, usually with a pair of particularly large. Although some species, especially in the Anthiadinae subfamily, only feed on zooplankton and they are typically ambush predators, hiding in cover on the reef and darting out to grab passing prey. Their bright colours are most likely a form of disruptive camouflage, many species are protogynous hermaphrodites, meaning they start out as females and change sex to male later in life. They produce large quantities of eggs and their larvae are planktonic, as other fish, serranids harbour parasites, including nematodes, cestodes, digeneans, monogeneans, isopods, and copepods. A study conducted in New Caledonia has shown that coral reef-associated serranids harbour about 10 species of parasites per fish species, recent molecular classifications challenge the validity of the genera Cromileptes and Anyperodon. Each of these two genera has a species, which were included in the same clade as species of Epinephelus in a study based on five different genes. Froese, Rainer, and Daniel Pauly, eds, a compendium of fossil marine animal genera
32.
Scombridae
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The Scombridae family of the mackerels, tunas, and bonitos includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies, all species are in the subfamily Scombrinae, except the butterfly kingfish, which is the sole member of subfamily Gasterochismatinae. Scombrids have two fins and a series of finlets behind the rear dorsal fin and anal fin. The caudal fin is divided and rigid, with a slender. The first dorsal fin and the fins are normally retracted into body grooves. Species lengths vary from the 20 cm of the island mackerel to the 4.58 m recorded for the immense Atlantic bluefin tuna, scombrids are generally predators of the open ocean, and are found worldwide in tropical and temperate waters. They are capable of speed, due to a highly streamlined body. Some members of the family, in particular the tunas, are notable for being partially endothermic, other adaptations include a large amount of red muscle, allowing them to maintain activity over long periods. Two of the fastest recorded scombrids are the wahoo and the yellowfin tuna, a compendium of fossil marine animal genera. Media related to Scombridae at Wikimedia Commons Skaphandrus. com Scombridae
33.
Swordfish
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Swordfish, also known as broadbills in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood and these fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of 550 m. They commonly reach 3 m in length, and the maximum reported is 4.55 m in length and 650 kg in weight and they are the sole member of their family, Xiphiidae. The swordfish is named after its bill, which resembles a sword and this makes it superficially similar to other billfish such as marlin, but upon examination, their physiology is quite different and they are members of different families. They commonly reach 3 m in length, and the maximum reported is 4.55 m in length and 650 kg in weight, the International Game Fish Associations all-tackle angling record for a swordfish was a 1,182 lb specimen taken off Chile in 1953. Females are larger than males, and Pacific swordfish reach a greater size than northwest Atlantic and they reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years. The oldest swordfish found in a recent study were a 16-year-old female, swordfish ages are derived, with difficulty, from annual rings on fin rays rather than otoliths, since their otoliths are small in size. Swordfish are ectothermic animals, however, along some species of sharks, they have special organs next to their eyes to heat their eyes. Temperatures of 10 to 15 °C above the water temperature have been measured. The heating of the eyes greatly improves their vision, and consequently improves their ability to catch prey, of the 25, 000+ fish species, only 22 are known to have a mechanism to conserve heat. These include the swordfish, marlin, tuna, and some sharks, contrary to popular belief, the sword is not used to spear, but instead may be used to slash at its prey to injure the prey animal, to make for an easier catch. Mainly, the swordfish relies on its speed and agility in the water to catch its prey. It is undoubtedly among the fastest fish, but the basis for the frequently quoted speed of 97 km/h is unreliable, swordfish prefer water temperatures between 18 and 22 °C, but have the widest tolerance among billfish, and can be found from 5 to 27 °C. This highly migratory species typically moves towards colder regions to feed during the summer, swordfish feed daily, most often at night, when they rise to surface and near-surface waters in search of smaller fish. During the day, they occur to depths of 550 m and have exceptionally been recorded as deep as 2,878 m. Adults feed on a range of pelagic fish, such as mackerel, barracudinas, silver hake, rockfish, herring, and lanternfishes, but they also take demersal fish, squid. Large prey are typically slashed with the sword, while small are swallowed whole and they swim alone or in very loose aggregations, separated by as much as 10 m from a neighboring swordfish
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Istiophoridae
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A marlin is a fish from the family Istiophoridae, which includes about 10 species. It has a body, a spear-like snout or bill. Its common name is thought to derive from its resemblance to a sailors marlinspike, even more so than their close relatives, the scombrids, marlins are fast swimmers, reaching speeds of about 80 km/h. They are popular sporting fish in tropical areas, the marlins are perciform fish, most closely related to the swordfish and Scombridae. On the 85th day, Santiago, the old fisherman, hooks a resolute marlin, marlin fishing Sailfish Froese, Rainer, and Daniel Pauly, eds. A compendium of fossil marine animal genera, ghost Fish Revelation May Alter Marlins Status from National Public Radio
35.
Nototheniidae
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The cod icefishes or nothothens are the family Nototheniidae of acanthopterygian fishes. They are traditionally placed in the perciform assemblage together with their relatives and they are largely found in the Southern Ocean and off the coast of Antarctica. As the dominant Antarctic fish taxa, they occupy both sea-bottom and water-column ecological niches, the spleen may be used to remove ice crystals from circulating blood. As the chilly subantarctic waters averages –1 to 4°C, most Antarctic species have antifreeze glycoproteins in their blood, some species exhibit polymorphism, for example, the circum-Antarctic Trematomus newnesi exists as two morphs in the Ross Sea, the typical morph and a large-mouthed/broad-headed morph. As the major resource in the Southern Ocean, notothens are under increasing pressure from commercial fishing
36.
Fish anatomy
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Fish anatomy is the study of the form or morphology of fishes. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish, the anatomy of fish is often shaped by the physical characteristics of water, the medium in which fish live. Water is much denser than air, holds a small amount of dissolved oxygen. The body of a fish is divided into a head, trunk and tail, the skeleton, which forms the support structure inside the fish, is either made of cartilage, in cartilaginous fish, or bone in bony fish. The main skeletal element is the column, composed of articulating vertebrae which are lightweight yet strong. The ribs attach to the spine and there are no limbs or limb girdles. The main external features of the fish, the fins, are composed of bony or soft spines called rays which. They are supported by the muscles which compose the main part of the trunk, the heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision, there is an inner ear but no external or middle ear. Sharks and rays are basal fish with numerous primitive anatomical features similar to those of ancient fish and their bodies tend to be dorso-ventrally flattened, they usually have five pairs of gill slits and a large mouth set on the underside of the head. The dermis is covered with separate dermal placoid scales and they have a cloaca into which the urinary and genital passages open, but not a swim bladder. Cartilaginous fish produce a number of large, yolky eggs. Some species are ovoviviparous and the young develop internally but others are oviparous, the bony fish lineage shows more derived anatomical traits, often with major evolutionary changes from the features of ancient fish. They have a skeleton, are generally laterally flattened, have five pairs of gills protected by an operculum. The dermis is covered with overlapping scales, bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca. They mostly spawn a number of small eggs with little yolk which they broadcast into the water column. Fish have a variety of different body plans, at the broadest level their body is divided into head, trunk, and tail, although the divisions are not always externally visible. The body is fusiform, a streamlined body plan often found in fast-moving fish
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Anatomical terms of location
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Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. All vertebrates have the basic body plan – they are strictly bilaterally symmetrical in early embryonic stages. That is, they have left and right halves if divided down the centre. For these reasons, the directional terms can be considered to be those used in vertebrates. By extension, the terms are used for many other organisms as well. While these terms are standardized within specific fields of biology, there are unavoidable, sometimes dramatic, for example, differences in terminology remain a problem that, to some extent, still separates the terminology of human anatomy from that used in the study of various other zoological categories. The vertebrates and Craniata share a heritage and common structure. To avoid ambiguities this terminology is based on the anatomy of each animal in a standard way, for humans, one type of vertebrate, anatomical terms may differ from other forms of vertebrates. Thus what is on top of a human is the head, whereas the top of a dog may be its back, for example, many species are not even bilaterally symmetrical. In these species, terminology depends on their type of symmetry, all descriptions are with respect to the organism in its standard anatomical position, even when the organism in question has appendages in another position. This helps avoid confusion in terminology when referring to the organism in different postures. In humans, this refers to the body in a position with arms at the side. While the universal vertebrate terminology used in medicine would work in human medicine. Many anatomical terms can be combined, either to indicate a position in two axes simultaneously or to indicate the direction of a movement relative to the body, for example, anterolateral indicates a position that is both anterior and lateral to the body axis. There is no limit to the contexts in which terms may be modified to qualify each other in such combinations. Generally the modifier term is truncated and an o or an i is added in prefixing it to the qualified term, where desirable three or more terms may be agglutinated or concatenated, as in anteriodorsolateral. Such terms sometimes used to be hyphenated, but the tendency is to omit the hyphen. There is however little basis for any rule to interfere with choice of convenience in such usage
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Cladistics
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Therefore, members of a group are assumed to share a common history and are considered to be closely related. The techniques and nomenclature of cladistics have been applied to other disciplines, Cladistics in the original sense refers to a particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole field. What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard in 1921, Hennig referred to his own approach as phylogenetic systematics. Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal, originally conceived, if only in essence, by Willi Hennig in a book published in 1950, cladistics did not flourish until its translation into English in 1966. Today, cladistics is the most popular method for constructing phylogenies from morphological, unlike phenetics, cladistics is specifically aimed at reconstructing evolutionary histories. The way for computational phylogenetics was paved by phenetics, a set of commonly used from the 1950s to 1980s. Phenetics did not try to reconstruct phylogenetic trees, rather, it tried to build dendrograms from similarity data, the cladistic method interprets each character state transformation implied by the distribution of shared character states among taxa as a potential piece of evidence for grouping. The outcome of an analysis is a cladogram – a tree-shaped diagram that is interpreted to represent the best hypothesis of phylogenetic relationships. Cladists contend that these models are unjustified, every cladogram is based on a particular dataset analyzed with a particular method. Different datasets and different methods, not to mention violations of the mentioned assumptions, only scientific investigation can show which is more likely to be correct. Since the cladograms provide competing accounts of events, at most one of them is correct. Within the primates, all anthropoids are hypothesized to have had a common ancestor all of whose descendants were anthropoids, the prosimians, on the other hand, form a paraphyletic taxon. When two or more taxa that are not nested within each other share a plesiomorphy, it is a symplesiomorphy, symplesiomorphies do not mean that the taxa that exhibit that character state are necessarily closely related. For example, Reptilia is traditionally characterized by being cold-blooded, whereas birds are warm-blooded, an apomorphy or derived state is an innovation. It can thus be used to diagnose a clade – or even to help define a clade name in phylogenetic nomenclature, features that are derived in individual taxa are called autapomorphies. Autapomorphies express nothing about relationships among groups, clades are identified by synapomorphies, for example, the possession of digits that are homologous with those of Homo sapiens is a synapomorphy within the vertebrates. The tetrapods can be singled out as consisting of the first vertebrate with such digits homologous to those of Homo sapiens together with all descendants of this vertebrate and it is therefore inferred to have evolved by convergence or reversal. Both mammals and birds are able to maintain a constant body temperature
39.
Paraphyletic
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In taxonomy, a group is paraphyletic if it consists of the groups last common ancestor and all descendants of that ancestor excluding a few—typically only one or two—monophyletic subgroups. The group is said to be paraphyletic with respect to the excluded subgroups, the term is commonly used in phylogenetics and in linguistics. The term was coined to apply to well-known taxa like reptiles which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that all extant reptiles as well as the extinct synapsids—except for mammals. Other commonly recognized paraphyletic groups include fish, monkeys and lizards, if many subgroups are missing from the named group, it is said to be polyparaphyletic. A paraphyletic group cannot be a clade, which is a monophyletic group, groups that include all the descendants of a common ancestor are said to be monophyletic. A paraphyletic group is a group from which one or more subsidiary clades is excluded to form a separate group. Ereshefsky has argued that paraphyletic taxa are the result of anagenesis in the group or groups. For example, dinosaurs are paraphyletic with respect to birds because birds possess many features that dinosaurs lack, a group whose identifying features evolved convergently in two or more lineages is polyphyletic. More broadly, any taxon that is not paraphyletic or monophyletic can be called polyphyletic and these terms were developed during the debates of the 1960s and 70s accompanying the rise of cladistics. The prokaryotes, because they exclude the eukaryotes, a descendant group, bacteria and Archaea are prokaryotes, but archaea and eukaryotes share a common ancestor that is not ancestral to the bacteria. The prokaryote/eukaryote distinction was proposed by Edouard Chatton in 1937 and was accepted after being adopted by Roger Stanier. The botanical code abandoned consideration of bacterial nomenclature in 1975, currently, dicotyledons are paraphyletic because the group excludes monocotyledons. Dicotyledon has not been used as an ICBN classification for decades, phylogenetic analysis indicates that the monocots are a development from a dicot ancestor. Excluding monocots from the dicots makes the latter a paraphyletic group, the order Artiodactyla, because it excludes Cetaceans. In the ICZN Code, the two taxa are orders of equal rank, molecular studies, however, have shown that the Cetacea descend from the Artiodactyl ancestors, although the precise phylogeny within the order remains uncertain. Without the Cetacean descendants the Artiodactyls must be paraphyletic, the class Reptilia as traditionally defined, because it excludes birds and mammals. In the ICZN Code, the three taxa are classes of equal rank, however, mammals hail from the synapsids and birds are descended from the dinosaurs, both of which are reptiles
40.
Scorpaeniformes
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The Scorpaeniformes are a diverse order of ray-finned fish, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species with over 1,320, scorpaeniform fishes are carnivorous, mostly feeding on crustaceans and on smaller fish. Most species live on the sea bottom in shallow waters, although species are known from deep water, from the midwater. They typically have spiny heads, and rounded pectoral and caudal fins. Most species are less than 30 cm in length, but the size range of the order varies from the velvetfishes, which can be just 2 cm long as adults, to the lingcod. The division of Scorpaeniformes into families is not settled, accounts range from 26 to 35 families, a compendium of fossil marine animal genera
41.
Tetraodontiformes
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The Tetraodontiformes are an order of highly derived ray-finned fish, also called the Plectognathi. Sometimes these are classified as a suborder of the order Perciformes and they have no close relatives, and descend from a line of coral-dwelling species that emerged around 80 million years ago. Various bizarre forms are included here, all departures from the streamlined body plan typical of most fishes. These forms range from nearly square or triangular, globose to laterally compressed and triggerfish. They range in size from Rudarius excelsus, measuring just 2 cm in length, to the ocean sunfish, most members of this order, except for the family Balistidae, are ostraciiforms, meaning the body is rigid and incapable of lateral flexure. Because of this, they are slow-moving and rely on their pectoral, dorsal, anal, however, movement is usually quite precise, dorsal and anal fins aid in manoeuvring and stabilizing. In most species, all fins are simple, small, and rounded, except for the fins which. Again, in most members, the plates are covered over with skin. The tetraodontiform strategy seems to be defense at the expense of speed, with all species fortified with scales modified into strong plates or spines — or with tough, leathery skin. Many species of the Tetraodontidae, Triodontidae, and Diodontidae are further protected from predation by tetrodotoxin, tetraodontiforms have highly modified skeletons, with no nasal, parietal, infraorbital, or lower rib bones. The bones of the jaw are modified and fused into a sort of beak and this is alluded to in their name, derived from the Greek words tetra meaning four and odous meaning tooth and the Latin forma meaning shape. Counting these teeth-like bones is a way of distinguishing similar families, for example, the Tetraodontidae, Triodontidae, the Molidae are conspicuous even within this oddball order, they lack swim bladders and spines, and are propelled by their very tall dorsal and anal fins. The caudal peduncle is absent and the fin is reduced to a stiff rudder-like structure. Molids are pelagic rather than reef-associated and feed on soft-bodied invertebrates, tree of Life, Tetraodontiformes Sepkoski, Jack. A compendium of fossil marine animal genera
42.
Flatfish
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A flatfish is a member of the order Pleuronectiformes of ray-finned demersal fishes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both lie on one side of the head, one or the other migrating through. Some species face their left sides upward, some face their right sides upward, many important food fish are in this order, including the flounders, soles, turbot, plaice, and halibut. Some flatfish can camouflage themselves on the ocean floor. Over 700 species are in the 11 families, the largest families are Bothidae, Cynoglossidae, Paralichthyidae, Pleuronectidae, and Soleidae, with more than 100 species each. Some families are the results of relatively recent splits, for example, the Achiridae were classified as a subfamily of Soleidae in the past, and the Samaridae were considered a subfamily of the Pleuronectidae. The Pleuronectidae may be split further still, as some authorities elevate Paralichthodinae, Poecilopsettinae, the taxonomy of some groups is in need of a review, as the last monograph covering the entire order was John Roxborough Normans Monograph of the Flatfishes published in 1934. New species are described with some regularity and undescribed species likely remain, hybrids are well known in flatfishes. The Pleuronectidae, of fishes, have the largest number of reported hybrids. Two of the most famous intergeneric hybrids are between the European plaice and European flounder in the Baltic Sea, and between the English sole and starry flounder in Puget Sound. The offspring of the species pair is popularly known as the hybrid sole and was initially believed to be a valid species in its own right. Flatfishes are found in worldwide, ranging from the Arctic, through the tropics. Most species are found in depths between 0 and 500 m, but a few have been recorded from depths in excess of 1,500 m, none have been confirmed from the abyssal or hadal zones. Among the deepwater species, Symphurus thermophilus lives in congregating around ponds of sulphur at hydrothermal vents on the seafloor, no other flatfish is known from hydrothermal vents. Many species will enter brackish or fresh water, and a number of soles. The most obvious characteristic of the flatfish is its asymmetry, with both eyes lying on the side of the head in the adult fish. In some families, the eyes are usually on the side of the body. The primitive spiny turbots include equal numbers of right- and left-sided individuals, other distinguishing features of the order are the presence of protrusible eyes, another adaptation to living on the seabed, and the extension of the dorsal fin onto the head
43.
Fishes of the World
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Fishes of the World by Joseph S. Nelson is a standard reference for fish systematics. Now in its edition, the work is a comprehensive overview of the diversity and classification of the 30. The book begins with an overview of ichthyology, although it is not self-contained. After a short section on Chordata and non-fish taxa, the work lists all known fish families in a systematic fashion, each family gets at least one paragraph, and usually a body outline drawing, large families have subfamilies and tribes described as well. Notable genera and species are mentioned, while the book generally does not deal with the species-level diversity, the complexities of the higher taxa are described succinctly, with many references for difficult points. The book does not involve color illustrations, the fourth edition was the first to incorporate the wide use of DNA analysis, revising many earlier classifications. The first edition appeared in 1976, the second in 1984, the third in 1994, the fourth in March 2006, bell The Quarterly Review of Biology Vol.70, 232-233 http, //www. jstor. org/stable/3036281 Fishes of the World. Review by, Carl L. Hubbs Systematic Zoology Vol.27, 136-137 http, Review by, George C. Williams The Quarterly Review of Biology Vol.52, 215-216. Http, //www. jstor. org/stable/2824104 Fishes of the World by J. S. Nelson, Review by, Lynne R. Parenti Copeia Vol.1995, 262-264 http, //www. jstor. org/stable/1446836 Day, Julia J. Fishes of the World, 4th Edition
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National Museum of Natural History
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The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D. C. Opened in 1910, the museum on the National Mall was one of the first Smithsonian buildings constructed exclusively to hold the national collections and research facilities. The main building has an area of 1,500,000 square feet with 325,000 square feet of exhibition and public space. The museums collections contain over 126 million specimens of plants, animals, fossils, minerals, rocks, meteorites, human remains, the United States National Museum was founded in 1846 as part of the Smithsonian Institution. The museum was housed in the Smithsonian Institution Building, which is better known today as the Smithsonian Castle. A formal exhibit hall opened in 1858, the growing collection led to the construction of a new building, the National Museum Building. Covering a then-enormous 2.25 acres, it was built in just 15 months at a cost of $310,000, congress authorized construction of a new building on June 28,1902. The regents began considering sites for the new building in March, the D. C. architectural firm of Hornblower & Marshall was chosen to design the structure. Testing of the soil for the foundations was set for July 1903, the Natural History Building opened its doors to the public on March 17,1910, in order to provide the Smithsonian Institution with more space for collections and research. The building was not fully completed until June 1911, the structure cost $3.5 million dollars. The Neoclassical style building was the first structure constructed on the side of the National Mall as part of the 1901 McMillan Commission plan. In addition to the Smithsonians natural history collection, it housed the American history, art. Between 1981 and 2003, the National Museum of Natural History had 11 permanent, there were six directors alone between 1990 and 2002. Turnover was high as the directors were disenchanted by low levels of funding. Robert W. Fri was named the director in 1996. One of the largest donations in Smithsonian history was made during Fris tenure, kenneth E. Behring donated $20 million in 1997 to modernize the museum. Fri resigned in 2001 after disagreeing with Smithsonian leadership over the reorganization of the scientific research programs. J. Dennis OConnor, Provost of the Smithsonian Institution was named acting director of the museum on July 25,2001, eight months later, OConner resigned to become the vice president of research and dean of the graduate school at the University of Maryland
45.
Pomacanthus semicirculatus
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Pomacanthus semicirculatus is a ray-finned fish in the family Pomacanthidae. It is found in the Indo-West Pacific Ocean and it occasionally makes its way into the aquarium trade. The adult semicircle angelfish is a pale brownish-green colour and it is a deep-bodied, laterally compressed fish that can grow to a length of 35 centimetres. The mouth is positioned just above the tip of the snout, the scales have blue bases which gives the body a speckled effect. The fins, except for the pectorals, are rimmed in blue and so are the cheek, operculum, the dorsal fin has 13 spines and 20–23 soft rays and the anal fin has 3 spines and 18–22 soft rays. Both these fins have filaments that trail behind as the fish swims, the pectoral fins are pale yellow and have 19–21 soft rays. The juveniles in contrast, are marked from top to bottom with narrow white stripes. At the head end the stripes are fairly straight but they become curved as they approach the base of the tail. The juveniles gradually adopt the adult colouration when they are 8 to 16 centimetres, the semicircle angelfish is found in the Indo-Pacific region. Its range extends from the east coast of Africa to Fiji and Japan and it has also been seen sporadically off the east coast of Florida since 1999 and at Oahu, Hawaii since 2005. The semicircle angelfish is found on sheltered coral reefs, where it feeds on algae, the juveniles are very timid and difficult to approach
