1.
Precambrian
–
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
Precambrian
Precambrian
2.
Cambrian
–
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
Cambrian
–
Archeocyathids from the
Poleta formation in the
Death Valley area
Cambrian
–
Stromatolites of the Pika Formation (Middle Cambrian) near Helen Lake, Banff National Park, Canada
Cambrian
–
Trilobites were very common during this time
Cambrian
–
Anomalocaris was an early marine predator, among the various
arthropods of the time.
3.
Ordovician
–
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
Ordovician
–
External mold of Ordovician
bivalve showing that the original
aragonite shell dissolved on the sea floor, leaving a cemented mold for biological encrustation (
Waynesville Formation of Franklin County, Indiana).
Ordovician
–
A
diorama depicting Ordovician flora and fauna.
Ordovician
–
Nautiloids like
Orthoceras were among the largest predators in the Ordovician.
Ordovician
–
Fossiliferous limestone slab from the Liberty Formation (Upper Ordovician) of Caesar Creek State Park near Waynesville, Ohio.
4.
Silurian
–
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
Silurian
–
Ordovician -Silurian boundary on
Hovedøya,
Norway, showing gray Ordovician
sandstone and brown Silurian
mudstone. The layers have been overturned by the
Caledonian orogeny.
Silurian
–
Marine extinction intensity during the
Phanerozoic
Silurian
–
Silurian sea bed fossils collected from Wren's Nest Nature Reserve, Dudley UK
Silurian
–
Crinoid fragments in a Silurian (Pridoli) limestone (
Saaremaa, Estonia)
5.
Devonian
–
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
Devonian
–
The rocks of Lummaton Quarry in
Torquay in Devon played an early role in defining the Devonian period.
Devonian
–
Dunkleosteus, one of the largest armoured fish to ever roam the planet, lived during the late Devonian
Devonian
–
Enrolled phacopid
trilobite from the Devonian of Ohio
Devonian
–
The common tabulate coral
Aulopora from the Middle Devonian of Ohio – view of colony origin encrusting a
brachiopod valve
6.
Carboniferous
–
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
Carboniferous
–
Generalized geographic map of the
United States in Middle
Pennsylvanian time.
Carboniferous
–
Lower Carboniferous marble in Big Cottonwood Canyon,
Wasatch Mountains,
Utah.
Carboniferous
–
Etching depicting some of the most significant plants of the Carboniferous.
Carboniferous
–
Ancient in situ
lycopsid, probably
Sigillaria, with attached
stigmarian roots.
7.
Permian
–
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
Permian
–
Selwyn Rock, South Australia - an exhumed
glacial pavement of Permian age
Permian
–
Geography of the Permian world
Permian
–
Hercosestria cribrosa, a
reef -forming productid brachiopod (Middle Permian, Glass Mountains, Texas).
Permian
–
Edaphosaurus pogonias and
Platyhystrix - Early Permian, North America and Europe
8.
Triassic
–
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
Triassic
–
Triassic flora as depicted in
Meyers Konversations-Lexikon (1885–90)
Triassic
–
230 Ma plate tectonic reconstruction
Triassic
–
Middle Triassic marginal marine sequence, southwestern
Utah
Triassic
–
Staurikosaurus feeding on a dicynodont, in geopark Paleorrota.
9.
Jurassic
–
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
Jurassic
–
Various
dinosaurs roamed forests of similarly large
conifers during the Jurassic period.
Jurassic
–
Jurassic limestones and marls (the
Matmor Formation) in southern
Israel.
Jurassic
–
The late Jurassic
Morrison Formation in
Colorado is one of the most fertile sources of dinosaur fossils in North America.
Jurassic
–
Gigandipus, a
dinosaur footprint in the Lower Jurassic
Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern
Utah.
10.
Cretaceous
–
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
Cretaceous
–
Drawing of fossil jaws of
Mosasaurus hoffmanni, from the
Maastrichtian of
Dutch Limburg, by Dutch geologist
Pieter Harting (1866).
Cretaceous
–
Although the first representatives of leafy trees and true grasses emerged in the Cretaceous, the flora was still dominated by conifers like
Araucaria (Here: Modern Araucaria araucana in Chile).
Cretaceous
–
Tyrannosaurus rex, one of the largest land predators of all time, lived during the late Cretaceous.
Cretaceous
–
Up to 2 m-long
Velociraptor was likely feathered and roamed the late Cretaceous.
11.
Paleogene
–
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
Paleogene
–
Scene featuring typical Eocene (Mid-Paleogene) flora and fauna
12.
Neogene
–
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
Neogene
–
Scene featuring Miocene (Early Neogene) fauna
13.
Toque macaque
–
The toque macaque is a reddish-brown-coloured Old World monkey endemic to Sri Lanka, where it is known as the rilewa or rilawa. With age, the face of females turn slightly pink, prominent in the subsp. M. s. sinica is found from the Vavuniya, Mannar, up to the lowlands of Anuradhapura, Polonnaruwa, Puttalam, and Kurunegala along the zone of Monaragala. M. s. aurifrons can be found sympatrically with subsp, sinica within intermediate regions of the country, such as Kegalle, parts of Kurunegala. They are also found in parts of the island including Galle. M. s. opisthomelas is recently identified as a separate subspecies and it can be found in the entire south-western region of central hill, and Nuwara Eliya districts. They can be seen around the Hakgala Botanical Garden and other cold climatic montane forest patches, S. opisthomelas is similar to subsp. Aurifrons, but has a fur and contrasting golden color in the anterior part of its brown cap. The three subspecies can be identified through the orientation of their different hair patterns, the social status is highly structured in toque macaques, where they prevail dominance hierarchies among both males and females. Females change the number of composition within a troop. A troop may consist very few as 8 to large as 40, when the troop becomes too much, social tension and aggression towards each other arise, which giving some individuals to flee from the troop. This is remarkable in adults and sub adults, where a troop may consist largely with females, newly appointed alpha male also show aggressiveness towards females, which results flee. There are sightings, where there are fights between individuals of the same troop and some gets heavy wounds to cheeks, eyes. When in estrous, the females perineum becomes reddish in color and this change is a signal to the males that she is ready to mate. There is an average of 18 month between births, after a 5–6 month gestation period, female macaque give birth to a single offspring. Offspring hold on to their mothers for about 2 months, during this time they learn survival techniques and social skills critical for survival. The infants are born into their classes based on their mothers position in the troop. Young males are forced to abandon their troop when they are about 6–8 years of age and this prevents in-breeding and ensures that the current alpha male maintains his position in the troop
Toque macaque
–
Toque macaque
Toque macaque
–
Grooming behaviour
Toque macaque
–
Macaca sinica opisthomelas
14.
Yala National Park
–
Yala National Park is the most visited and second largest national park in Sri Lanka. The park consists of five blocks, two of which are now open to the public, and also adjoining parks, the blocks have individual names such as, Ruhuna National Park and Kumana National Park or Yala East for the adjoining area. It is situated in the southeast region of the country, and lies in Southern Province, the park covers 979 square kilometres and is located about 300 kilometres from Colombo. Yala was designated as a sanctuary in 1900, and. The park is best known for its variety of wild animals and it is important for the conservation of Sri Lankan elephants, Sri Lankan leopards and aquatic birds. There are six national parks and three wildlife sanctuaries in the vicinity of Yala, among the largest is Lunugamvehera National Park. The park is situated in the dry semi-arid climatic region and rain is received mainly during the northeast monsoon, Yala hosts a variety of ecosystems ranging from moist monsoon forests to freshwater and marine wetlands. It is one of the 70 Important Bird Areas in Sri Lanka, Yala harbours 215 bird species including six endemic species of Sri Lanka. The number of mammals that has recorded from the park is 44. The area around Yala has hosted several ancient civilizations, two important pilgrim sites, Sithulpahuwa and Magul Vihara, are situated within the park. The 2004 Indian Ocean tsunami caused damage on the Yala National Park and 250 people died in its vicinity. The number of visitors has been on the rise since 2009, in 1560 Spanish cartographer Cipriano Sanchez noted Yala in his map is abandoned for 300 years due to insalubrious conditions. Chief Justice Sir Alexander Johnston wrote an account on Yala in 1806 after travelling from Trincomalee to Hambantota. On March 23,1900 the government proclaimed Yala and Wilpattu reserves under the Forest Ordinance, initially the extent of the reserve was 389 square kilometres between the Menik and Kumbukkan Rivers. At that time the reserve did not bear the name Yala, the Game Protection Society was instrumental in establishing the reserve. The forest area between Palatupana and Yala was declared a site reserved only for the resident sportsmen. Henry Engelbrecht was appointed as the first park warden, on 1 March 1938, Yala became a national park when the Flora and Fauna Protection Ordinance was passed into law by D. S. Senanayake, the minister of agriculture. The park consists of five blocks, subsequently four other blocks were incorporated to the park
Yala National Park
–
Patanangala, a rock outcrop in the Yala beach
Yala National Park
–
Map of Yala National Park
Yala National Park
–
Surface water becomes critical in the dry season
15.
Sri Lanka
–
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, is an island country in South Asia near south-east India. Sri Lanka has maritime borders with India to the northwest and the Maldives to the southwest, Sri Lankas documented history spans 3,000 years, with evidence of pre-historic human settlements dating back to at least 125,000 years. Its geographic location and deep harbours made it of strategic importance from the time of the ancient Silk Road through to World War II. Sri Lanka was known from the beginning of British colonial rule until 1972 as Ceylon, Sri Lankas recent history has been marred by a thirty-year civil war which decisively ended when the Sri Lankan military defeated the Liberation Tigers of Tamil Eelam in 2009. A diverse and multicultural country, Sri Lanka is home to many religions, ethnic groups, in addition to the majority Sinhalese, it is home to large groups of Sri Lankan and Indian Tamils, Moors, Burghers, Malays, Kaffirs and the aboriginal Vedda. Sri Lanka has a rich Buddhist heritage, and the first known Buddhist writings of Sri Lanka, Sri Lanka is a republic and a unitary state governed by a semi-presidential system. The legislative capital, Sri Jayawardenepura Kotte, is a suburb of the capital and largest city. Along with the Maldives, Sri Lanka is one of the two countries in South Asia that are rated among high human development on the Human Development Index. In antiquity, Sri Lanka was known to travellers by a variety of names, according to the Mahavamsa, the legendary Prince Vijaya named the land Tambapanni, because his followers hands were reddened by the red soil of the area. In Hindu mythology, such as the Mahabharata, the island was referred to as Lankā, in Tamil, the island is referred to as Eelam. Ancient Greek geographers called it Taprobanā or Taprobanē from the word Tambapanni, as a British crown colony, the island was known as Ceylon, it achieved independence as the Dominion of Ceylon in 1948. The country is known in Sinhalese as Śrī Laṃkā and in Tamil as Ilaṅkai, in 1972, its formal name was changed to Free, Sovereign and Independent Republic of Sri Lanka. Later in 1978 it was changed to the Democratic Socialist Republic of Sri Lanka, as the name Ceylon still appears in the names of a number of organisations, the Sri Lankan government announced in 2011 a plan to rename all those over which it has authority. The pre-history of Sri Lanka goes back 125,000 years, the era spans the Palaeolithic, Mesolithic and early Iron Ages. Among the Paleolithic human settlements discovered in Sri Lanka, Pahiyangala and it is said that Kubera was overthrown by his demon stepbrother Ravana, the powerful emperor who built a mythical flying machine named Dandu Monara. The modern city of Wariyapola is described as Ravanas airport, early inhabitants of Sri Lanka were probably ancestors of the Vedda people, an indigenous people numbering approximately 2,500 living in modern-day Sri Lanka. According to the Mahāvamsa, a written in Pāḷi, the original inhabitants of Sri Lanka are the Yakshas and Nagas. Ancient cemeteries that were used before 600BC and other signs of advanced civilization has also discovered in Sri Lanka
Sri Lanka
–
Avukana Buddha statue, a 12 metres (39 ft) standing Buddha statue belongs to the reign of
Dhatusena of Anuradhapura, 5th century
Sri Lanka
–
Flag
Sri Lanka
–
Ptolemy's world map of Ceylon, first century CE, in a 1535 publication.
Sri Lanka
–
The
Sigiriya rock fortress
16.
Biological classification
–
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
Biological classification
–
Title page of
Systema Naturae, Leiden, 1735
Biological classification
–
Evolution of the
vertebrates at class level, width of spindles indicating number of families. Spindle diagrams are typical for
Evolutionary taxonomy
Biological classification
–
The same relationship, expressed as a
cladogram typical for
cladistics
Biological classification
–
Type specimen for
Nepenthes smilesii, a tropical
pitcher plant.
17.
Animal
–
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
Animal
–
Carl Linnaeus, known as the father of modern
taxonomy
Animal
–
Had'n
Animal
–
The use of
love darts by the land snail
Monachoides vicinus is a form of
sexual selection
Animal
–
A
newt lung cell stained with
fluorescent dyes undergoing the early
anaphase stage of
mitosis
18.
Chordata
–
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
Chordata
Chordata
–
Craniate:
Hagfish
Chordata
–
Tunicates: sea squirts
Chordata
–
Cephalochordate:
Lancelet
19.
Mammal
–
Mammals are any vertebrates within the class Mammalia, a clade of endothermic amniotes distinguished from reptiles by the possession of a neocortex, hair, three middle ear bones and mammary glands. All female mammals nurse their young with milk, secreted from the mammary glands, Mammals include the largest animals on the planet, the great whales. The basic body type is a quadruped, but some mammals are adapted for life at sea, in the air, in trees. The largest group of mammals, the placentals, have a placenta, Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale. With the exception of the five species of monotreme, all modern mammals give birth to live young, most mammals, including the six most species-rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha, the next three biggest orders, depending on the biological classification scheme used, are the Primates, the Cetartiodactyla, and the Carnivora. Living mammals are divided into the Yinotheria and Theriiformes There are around 5450 species of mammal, in some classifications, extant mammals are divided into two subclasses, the Prototheria, that is, the order Monotremata, and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the group of the Metatheria, and include all living metatherians as well as many extinct ones. Much of the changes reflect the advances of cladistic analysis and molecular genetics, findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora. The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade, the early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the line that led to todays reptiles. Some mammals are intelligent, with some possessing large brains, self-awareness, Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals, singing, and echolocation. Mammals can organize themselves into fission-fusion societies, harems, and hierarchies, most mammals are polygynous, but some can be monogamous or polyandrous. They provided, and continue to provide, power for transport and agriculture, as well as commodities such as meat, dairy products, wool. Mammals are hunted or raced for sport, and are used as model organisms in science, Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is accepted, McKenna & Bell and Wilson & Reader provide useful recent compendiums. Though field work gradually made Simpsons classification outdated, it remains the closest thing to a classification of mammals
Mammal
–
Goat kids will stay with their mother until they are weaned.
Mammal
20.
Primate
–
A primate is a mammal of the order Primates. In taxonomy, primates include two distinct lineages, strepsirrhines and haplorhines, Primates arose from ancestors that lived in the trees of tropical forests, many primate characteristics represent adaptations to life in this challenging three-dimensional environment. Most primate species remain at least partly arboreal, with the exception of humans, who inhabit every continent except for Antarctica, most primates live in tropical or subtropical regions of the Americas, Africa and Asia. Based on fossil evidence, the earliest known true primates, represented by the genus Teilhardina, an early close primate relative known from abundant remains is the Late Paleocene Plesiadapis, c. Molecular clock studies suggest that the branch may be even older. The order Primates was traditionally divided into two groupings, prosimians and anthropoids. Prosimians have characteristics more like those of the earliest primates, and include the lemurs of Madagascar, lorisoids, simians include monkeys, apes and hominins. Simians are divided into two groups, catarrhine monkeys and apes of Africa and Southeast Asia and platyrrhine or New World monkeys of South, catarrhines consist of Old World monkeys, gibbons and great apes, New World monkeys include the capuchin, howler and squirrel monkeys. Humans are the only extant catarrhines to have spread successfully outside of Africa, South Asia, New primate species are still being discovered. More than 25 species were described in the decade of the 2000s. Considered generalist mammals, primates exhibit a range of characteristics. Some primates are primarily terrestrial rather than arboreal, but all species possess adaptations for climbing trees, locomotion techniques used include leaping from tree to tree, walking on two or four limbs, knuckle-walking, and swinging between branches of trees. Primates are characterized by large brains relative to other mammals, as well as a reliance on stereoscopic vision at the expense of smell. These features are developed in monkeys and apes and noticeably less so in lorises. Three-color vision has developed in some primates, most also have opposable thumbs and some have prehensile tails. Many species are dimorphic, differences include body mass, canine tooth size. Primates have slower rates of development than other similarly sized mammals and reach maturity later, depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members. The relationships among the different groups of primates were not clearly understood until relatively recently, for example, ape has been used either as an alternative for monkey or for any tailless, relatively human-like primate
Primate
–
A 1927 drawing of
chimpanzees, a
gibbon (top right) and two
orangutans (center and bottom center): The chimp in the upper left is
brachiating; the orangutan at the bottom center is
knuckle-walking.
Primate
Primate
–
The
Philippine tarsier, once considered a
prosimian, is now predominantly considered a
haplorhine.
Primate
–
Common brown lemur, a
strepsirrhine primate
21.
Haplorhini
–
Haplorrhini is a clade containing the tarsiers and the simians. The name is also spelt Haplorrhini, the simians include catarrhines, and the platyrrhines. The extinct omomyids, which are considered to be the most basal haplorhines, are believed to be closely related to the tarsiers than to other haplorhines. Haplorhines share a number of derived features that distinguish them from the strepsirrhine wet-nosed primates, the haplorhine upper lip, which has replaced the ancestral rhinarium found in strepsirrhines, is not directly connected to their nose or gum, allowing a large range of facial expressions. Their brain-to-body mass ratio is greater than the strepsirrhines. Haplorhines have a plate, unlike the postorbital bar found in strepsirrhines. All anthropoids have a uterus, tarsiers have a bicornate uterus like the strepsirrhines. Most species typically have single births, although twins and triplets are common for marmosets, despite similar gestation periods, haplorhine newborns are relatively much larger than strepsirrhine newborns, but have a longer dependence period on their mother. This difference in size and dependence is credited to the complexity of their behavior. The taxonomic name Haplorhini derives from the Ancient Greek haploûs and rhinos and it refers to the lack of a rhinarium or wet nose, which is found in many mammals, including strepsirrhine primates. Haplorhini and its sister clade, Strepsirrhini, diverged about 65 million years ago, the fossil Archicebus may be similar to the most recent common ancestor at this time. The other major clade within Haplorhini, the simians, is divided into two parvorders, Platyrrhini and Catarrhini, the New World monkeys split from catarrhines about 40 mya, while the apes diverged from Old World monkeys about 25 mya. The available fossil evidence indicates both the hominoid and cercopithecoid clades originated in Africa. The following is the listing of the living families, and their placement in the Order Primates, ORDER PRIMATES Suborder Strepsirrhini, lemurs, lorises
Haplorhini
–
Haplorhines Temporal range:
Late Paleocene –
Holocene
22.
Ernst Haeckel
–
The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures. As a philosopher, Ernst Haeckel wrote Die Welträtsel, the genesis for the term world riddle, Ernst Haeckel was born on 16 February 1834, in Potsdam. In 1852, Haeckel completed studies at the Domgymnasium, the high school of Merseburg. He then studied medicine in Berlin and Würzburg, particularly with Albert von Kölliker, Franz Leydig, Rudolf Virchow, together with Hermann Steudner he attended botany lectures in Würzburg. In 1857, Haeckel attained a doctorate in medicine, and afterwards he received a license to practice medicine, the occupation of physician appeared less worthwhile to Haeckel, after contact with suffering patients. Between 1859 and 1866, Haeckel worked on many phyla such radiolarians, poriferans, during a trip to the Mediterranean, Haeckel named nearly 150 new species of radiolarians. In 1867, he married Agnes Huschke and their son Walter was born in 1868, their daughters Elizabeth in 1871 and Emma in 1873. In 1869, he traveled as a researcher to Norway, in 1871 to Croatia, and in 1873 to Egypt, Turkey, Haeckel retired from teaching in 1909, and in 1910 he withdrew from the Evangelical church. Haeckels wife, Agnes, died in 1915, and Haeckel became substantially frailer, with a broken leg and he sold his Villa Medusa in Jena in 1918 to the Carl Zeiss foundation, and it presently contains a historic library. Haeckel died on 9 August 1919, Haeckels political beliefs were influenced by his affinity for the German Romantic movement coupled with his acceptance of a form of Lamarckism. Rather than being a strict Darwinian, Haeckel believed that the characteristics of an organism were acquired through interactions with the environment and he believed the social sciences to be instances of applied biology, and that phrase was picked up and used for Nazi propaganda. In 1905, Haeckel founded a group called the Monist League to promote his religious and this group lasted until 1933 and included such notable members as Wilhelm Ostwald, Georg von Arco, Helene Stöcker and Walter Arthur Berendsohn. Haeckel was the first person known to use the term First World War. Shortly after the start of the war Haeckel wrote, There is no doubt that the course, Haeckel was a zoologist, an accomplished artist and illustrator, and later a professor of comparative anatomy. For example, Haeckel described and named hypothetical ancestral microorganisms that have never been found and he was one of the first to consider psychology as a branch of physiology. He also proposed the kingdom Protista in 1866 and his chief interests lay in evolution and life development processes in general, including development of nonrandom form, which culminated in the beautifully illustrated Kunstformen der Natur. Haeckel did not support natural selection, rather believing in Lamarckism and it proposed a link between ontogeny and phylogeny, summed up by Haeckel in the phrase ontogeny recapitulates phylogeny. His concept of recapitulation has been refuted in the form he gave it, the strong recapitulation hypothesis views ontogeny as repeating forms of the ancestors, while weak recapitulation means that what is repeated is the ancestral embryonic development process
Ernst Haeckel
–
Ernst Haeckel
Ernst Haeckel
–
Sea anemones from Ernst Haeckel's
Kunstformen der Natur (Art forms of Nature) of 1904
Ernst Haeckel
–
Haeckel (left) with
Nicholai Miklukho-Maklai, his assistant, in the
Canaries, 1866
23.
Callitrichidae
–
The Callitrichidae are a family of New World monkeys, including marmosets and tamarins. At times, this group of animals has been regarded as a subfamily, called Callitrichinae and this taxon was traditionally thought to be a primitive lineage, from which all the larger-bodied platyrrhines evolved. However, some argue that callitrichids are actually a dwarfed lineage. Ancestral stem-callitrichids likely were normal-sized ceboids that were dwarfed through evolutionary time and they are the smallest of the simian primates. They eat insects, fruit, and the sap or gum from trees, the marmosets rely quite heavily on tree exudates, with some species considered obligate exudativores. Callitrichids typically live in small, territorial groups of five or six animals. Their social organization is unique among primates and is called a cooperative polyandrous group and this communal breeding system involves groups of multiple males and females, but only one female is reproductively active. Females mate with more than one male and each shares the responsibility of carrying the offspring and they are the only primate group that regularly produces twins, which constitute over 80% of births in species that have been studied. Unlike other male primates, male callitrichids generally provide as much care as females. Parental duties may include carrying, protecting, feeding, comforting, in some cases, such as in the cotton-top tamarin, males, particularly those that are paternal, will even show a greater involvement in caregiving than females. The typical social structure seems to constitute a group, with several of their previous offspring living in the group
Callitrichidae
–
Callitrichidae
Callitrichidae
–
Emperor tamarin (Saguinus imperator)
24.
Cebidae
–
The Cebidae are one of the five families of New World monkeys now recognised. It includes the capuchin monkeys and squirrel monkeys and these species are found throughout tropical and subtropical South and Central America. Cebid monkeys are arboreal animals that only travel on the ground. They are generally small monkeys, ranging in size up to that of the capuchin, with a body length of 33 to 56 cm. They are somewhat variable in form and coloration, but all have the wide, flat and they are different from marmosets as they have additional molar tooth and a prehensile tail. They are omnivorous, mostly eating fruit and insects, although the proportions of these vary greatly between species. They have the formula,2.1.3. 2-32.1.3. 2-3 Females give birth to one or two young after a gestation period of between 130 and 170 days, depending on species. They are social animals, living in groups of five and forty individuals, with the smaller species typically forming larger groups. They are generally diurnal in habit, previously, New World monkeys were divided between Callitrichidae and this family. For a few recent years, marmosets, tamarins, and lion tamarins were placed as a subfamily in Cebidae, the most recent classification of New World monkeys again splits the callitrichids off, leaving only the capuchins and squirrel monkeys in this family
Cebidae
–
Cebidae Temporal range:
Late Oligocene [
citation needed] to present
Cebidae
–
White-fronted Capuchin (Cebus albifrons)
Cebidae
–
Common Squirrel Monkey (Saimiri sciureus)
25.
Aotidae
–
The night monkeys, also known as the owl monkeys or douroucoulis, are the members of the genus Aotus of New World monkeys. The only nocturnal monkeys, they are native to Panama and much of tropical South America, until 1983, all night monkeys were placed into only one or two species. He split Aotus into two groups, a northern, gray-necked group and a southern, red-necked group, a new species from the gray-necked group was recently described as A. jorgehernandezi. As is the case with some other splits in this genus, chromosome evidence has also been used as an argument for merging species, as was the case for considering infulatus a subspecies of A. azarae rather than a separate species. Fossil species have been assigned to genus, but only extant species are listed below. They are sometimes said to lack a tapetum lucidum, the layer behind the retina posessed by many nocturnal animals. Other sources say they have a tapetum lucidum composed of collagen fibrils and their ears are rather difficult to see, this is why their genus name, Aotus was chosen. There is little data on the weights of wild night monkeys, the male is slightly taller than the female, measuring 346 and 341 millimetres, respectively. Night monkeys can be found in Panama, Colombia, Ecuador, Peru, Brazil, Paraguay, Argentina, Bolivia, the species that live at higher elevations tend to have thicker fur than the monkeys at sea level. The night monkey can live in forests undisturbed by humans as well as forests that are recovering from human logging efforts, the name night monkey comes from the fact that all species are active at night and are, in fact, the only truly nocturnal monkeys. Night monkeys make a wide variety of vocal sounds, with up to eight categories of distinct calls. Unusual among the New World monkeys, they are monochromats, that is, they have no colour vision and they have a better spatial resolution at low light levels than other primates, which contributes to their ability to capture insects and move at night. Night monkeys live in groups consisting of a mated pair and their immature offspring. Family groups defend territories by vocal calls and scent marking, the night monkey is socially monogamous, and all night monkeys form pair bonds. Only one infant is born each year, the male is the primary caregiver, and the mother only carries the infant for the first week or so of its life. This is believed to have developed because it increases the survival of the infant, adults will occasionally be evicted from the group by same-sex individuals, either kin or outsiders. Most night monkey species are threatened by varying levels of habitat throughout their range, caused by agricultural expansion, cattle ranching, logging, armed conflict. They are also removed from wild for national and international trade and this trade is primarily for biomedical research and while much of it is legal, it is also continuing illegally from at least part of their range
Aotidae
–
Night monkeys
Aotidae
–
Three-striped night monkey
26.
Pitheciidae
–
The Pitheciidae are one of the five families of New World monkeys now recognised. Formerly, they were included in the family Atelidae, the family includes the titis, saki monkeys and uakaris. Most species are native to the Amazon region of Brazil, with some being found from Colombia in the north to Bolivia in the south, pithecids are small to medium-sized monkeys, ranging from 23 cm in head-body length for the smaller titis, to 44-49 cm for the uakaris. They have medium to long fur, in a range of colors, often with contrasting patches. They are diurnal and arboreal animals, found in forests from low-lying swamp to mountain slopes. They are predominantly herbivorous, eating fruit and seeds, although some species will also eat a small number of insects. Sakis and uakaris have a diastema between the canine and premolar teeth, but the titis, which have small canines for New World monkeys. All species have the formula,2.1.3.32.1.3.3 Females give birth to a single young after a gestation period of between four and six months, depending on species. The uakaris and bearded sakis are polygamous, living in groups of 8-30 individuals, each group has multiple males, which establish a dominance hierarchy amongst themselves. The titis and Pithecia sakis, by contrast, are monogamous, there are 54 currently recognized extant species of pithecid monkey, grouped into two subfamilies and four genera. Seven extinct genera known from the record are placed in the subfamily Pitheciinae
Pitheciidae
27.
Atelidae
–
The Atelidae are one of the five families of New World monkeys now recognised. It was formerly included in the family Cebidae, atelids are generally larger monkeys, the family includes the howler, spider, woolly, and woolly spider monkeys. They are found throughout the regions of Central and South America. Atelid monkeys are small to moderate in size, ranging from 34 to 72 cm in length, with the howler monkeys being the largest members of the group. They have long tails with a sensitive, almost hairless. The tail is used as fifth limb while moving through the trees where they make their homes. They also have nails on their fingers and toes, enabling them to climb, most species have predominantly dark brown, grey, or black fur, often with paler markings. These are arboreal and diurnal animals, with most species restricted to dense rain forest, although some howler monkey species are found in drier forests and they mainly eat fruit and leaves, although the smaller species, in particular, may also eat some small insects. They have the formula,2.1.3.32.1.3.3 Females give birth to a single infant after a gestation period of 180 to 225 days. In most species, individuals give birth every one to three years, and there is little, if any, seasonal peak in the number of births, atelid monkeys are typically polygamous, and live in social groups with anything up to twenty five adults, depending on species. Currently,29 species of monkey are recognized, grouped into five genera
Atelidae
–
Atelidae Temporal range:
Middle Miocene [
citation needed] to present
28.
Cercopithecidae
–
The Old World monkeys or Cercopithecidae are a family of catarrhines, the only family in the superfamily Cercopithecoidea in the clade of Catarrhini. However, a group of monkeys still survives in Gibraltar to this day. Old World monkeys include many of the most familiar species of primates, such as baboons. Old World monkeys are medium to large in size, and range from arboreal forms, such as the monkeys, to fully terrestrial forms. By superficial appearance, Old World monkeys are unlike apes in that most have tails and, unlike the New World monkeys, technically, the distinction of catarrhines from platyrrhines depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In platyrrhines, the nostrils face sideways, while in catarrhines, for example, the colobus monkeys have stubs for thumbs to assist with their arboreal movement, the proboscis monkey has an extraordinary nose, while the snub-nosed monkeys have almost no nose at all. The male mandrills penis is red and the scrotum is lilac, the coloration is more pronounced in dominant males. Most Old World monkeys are at least partially omnivorous, but all prefer plant matter, the Barbary macaques diet consists mostly of leaves and roots, though it will also eat insects and uses cedar trees as a water source. Gestation in the Old World monkeys lasts between five and seven months, births are usually single, although, as with humans, twins occur from time to time. The young are born relatively well-developed, and are able to cling onto their mothers fur with their hands from birth, compared with most other mammals, they take a long time to reach sexual maturity, with four to six years being typical of most species. In most species, daughters remain with their mothers for life, males leave the group on reaching adolescence, and find a new troop to join. In many species, only an adult male lives with each group, driving off all rivals. Group sizes are variable, even within species, depending on the availability of food. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey
Cercopithecidae
Cercopithecidae
–
Paracolobus chemeroni fossil
Cercopithecidae
–
Black-footed gray langur, Semnopithecus hypoleucos
29.
Hominoidea
–
Apes are a branch of Old World tailless anthropoid primates native to Africa and Southeast Asia. They are the group of Old World monkeys, together forming the catarrhine clade. They are distinguished from other primates by a degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation. There are two extant branches of the superfamily Hominoidea, the gibbons, or lesser apes, and the hominids, or great apes. The family Hylobatidae, the apes, include four genera and a total of sixteen species of gibbon, including the lar gibbon. They are highly arboreal and bipedal on the ground and they have lighter bodies and smaller social groups than great apes. The family Hominidae, the apes, includes orangutans, gorillas, chimpanzees. There are seven extant species of apes, two in the orangutans, two in the gorillas, two in the chimpanzees, and a single extant species, Homo sapiens, of modern humans. Recent evidence has changed our understanding of the relationships between the hominoids, especially regarding the lineage, and the traditionally used terms have become somewhat confused. Competing approaches re methodology and terminology are found among current scientific sources, see below, History of hominoid taxonomy and see Primate, Historical and modern terminology for discussions of the changes in scientific classification and terminology regarding hominoids. Except for gorillas and humans, hominoids are agile climbers of trees, most non-human hominoids are rare or endangered. The chief threat to most of the species is loss of tropical rainforest habitat. The great apes of Africa are also facing threat from the Ebola virus, currently considered to be the greatest threat to survival of African apes, Ebola is responsible for the death of at least one third of the species since 1990. Ape, from Old English apa, is a word of uncertain origin, the term has a history of rather imprecise usage—and of comedic or punning usage in the vernacular. Its earliest meaning was generally of any non-human anthropoid primate, as is still the case for its cognates in other Germanic languages, later, after the term monkey had been introduced into English, ape was specialized to refer to a tailless primate. Two tailless species of macaque still have names using ape, the Barbary ape of North Africa, Macaca sylvanus. Some, or – recently – all, hominoids are also called apes, ape has been used as a synonym for monkey or for naming any primate with a human-like appearance, particularly those without a tail. Thus the Barbary macaque, a kind of monkey, is called the Barbary ape
Hominoidea
Hominoidea
–
Like those of the orangutan, the shoulder joints of hominoids are adapted to
brachiation, or movement by swinging in tree branches.
Hominoidea
–
A series of images showing a gorilla utilizing a small tree trunk as a tool to maintain balance as she fished for aquatic herbs
30.
Cladistics
–
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
Cladistics
–
Peter Chalmers Mitchell in 1920
Cladistics
–
Diagrammatic representation of the
divergence of modern
taxonomic groups from their
common ancestor
Cladistics
–
Robert John Tillyard
31.
Species
–
In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
Species
–
John Ray
Species
–
Carl Linnaeus believed in the fixity of species.
32.
New World monkey
–
New World monkeys are the five families of primates that are found in Central and South America and portions of Mexico, Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Platyrrhini parvorder and the Ceboidea superfamily, platyrhini means flat-nosed, and their noses are flatter than those of other simians, with sideways-facing nostrils. Monkeys in the family Atelidae, such as the monkey, are the only primates to have prehensile tails. New World monkeys closest relatives are the simians, the Catarrhini. New World monkeys descend from African simians that colonized South America, New World monkeys differ slightly from Old World monkeys in several aspects. The most prominent phenotypic distinction is the nose, which is the feature used most commonly to distinguish between the two groups, the clade for the New World monkeys, Platyrrhini, means flat nosed. The noses of New World monkeys are flatter than the narrow noses of the Old World monkeys, New World monkeys are the only monkeys with prehensile tails—in comparison with the shorter, non-grasping tails of the anthropoids of the Old World. New World monkeys also typically lack the trichromatic vision of Old World monkeys, colour vision in New World primates relies on a single gene on the X-chromosome to produce pigments that absorb medium and long wavelength light, which contrasts with short wavelength light. As a result, males rely on a single medium/long pigment gene and are dichromatic, heterozygous females may possess two alleles with different sensitivities within this range, and so can display trichromatic vision. Platyrrhines also differ from Old World monkeys in that they have twelve premolars instead of eight, having a dental formula of 2.1.3.32.1.3.3 or 2.1.3.22.1.3.2. This is in contrast with Old World Anthropoids, including gorillas, chimps, bonobos, siamangs, gibbons, orangutans, and most humans, which share a dental formula of 2.1.2.32.1.2.3. Many New World monkeys are small and almost all are arboreal, unlike most Old World monkeys, many New World monkeys form monogamous pair bonds, and show substantial paternal care of young. They eat fruits, nuts, insects, flowers, bird eggs, spiders, unlike humans and most Old World monkeys, their thumbs are not opposable. About 40 million years ago, the Simiiformes infraorder split into the parvorders Platyrrhini and Catarrhini, the individuals whose descendents would become Platyrrhini are currently conjectured to have migrated to South America either on a raft of vegetation or via a land bridge. There are two possible rafting routes, either across the Atlantic Ocean from Africa or across the Caribbean from North America, however, there is no fossil record to support the hypothesis of a migration from North America. The land bridge hypothesis relies on the existence of Atlantic Ocean ridges and this would have either produced a single land bridge or a series of mid-Atlantic islands to act as stepping stones for the migration. The latter is now the favorite choice, the chromosomal content of the ancestor species appears to have been 2n =54. In extant species, the 2n value varies from 16 in the monkey to 62 in the woolly monkey
New World monkey
33.
Catarrhini
–
Catarrhini is one of the two subdivisions of the simians, the other being the plathyrrhine. The Catarrhine are all native to Africa and Asia, members of this parvorder are called catarrhines. The technical distinction between the New World platyrrhines and Old World catarrhines is the shape of their noses, the platyrrhines have nostrils which face sideways. The catarrhines have nostrils that face downwards. Catarrhines also never have tails, and have flat fingernails and toenails, a tubular ectotympanic. Most catarrhine species show sexual dimorphism and do not form a pair bond. Most, but not all, species live in social groups, like the platyrrhines, the catarrhines are generally diurnal, and have grasping hands and grasping feet. The apes – in both traditional and phylogenic nomenclature – are exclusively catarrhine species, in traditional usage, ape describes any tailless, larger, and more typically ground-dwelling species of catarrhine. Ape may be found as part of the name of such species. In phylogenic usage, the term ape applies only to the superfamily Hominoidea, the apes and Old World monkeys split from their New World monkey kin about 35 million years ago. The major catarrhine division occurred about 25 Mya, with the gibbons separating from the great apes about 15-19 Mya, therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey. Order PrimatesSuborder Strepsirrhini, lemurs, lorises, etc, in May 2005, dozens of new primate fossils, mainly single teeth, were discovered in the Bugti Hills of Pakistan. They were recognised as belonging to three new species, the three primates called Bugtipithecus inexpectans, Phileosimias kamali, and Phileosimias brahuiorum all date back to the Oligocene some 30 Mya – when monkeys dominated only Africa. These were small lemur-like catarrhines that prospered in an ancient tropical rainforest, possibly these Asian catarrhines led nowhere in evolution, a side branch from Eosimias. Other possible new catarrhine fossils have been uncovered in China, Thailand, disotell T. R. Noviello C. M. Raaum R. L. Sterner K. N. Stewart C. Catarrhine primate divergence dates estimated from complete mitochondrial genomes, concordance with fossil and nuclear DNA evidence
Catarrhini
34.
Old World monkey
–
The Old World monkeys or Cercopithecidae are a family of catarrhines, the only family in the superfamily Cercopithecoidea in the clade of Catarrhini. However, a group of monkeys still survives in Gibraltar to this day. Old World monkeys include many of the most familiar species of primates, such as baboons. Old World monkeys are medium to large in size, and range from arboreal forms, such as the monkeys, to fully terrestrial forms. By superficial appearance, Old World monkeys are unlike apes in that most have tails and, unlike the New World monkeys, technically, the distinction of catarrhines from platyrrhines depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In platyrrhines, the nostrils face sideways, while in catarrhines, for example, the colobus monkeys have stubs for thumbs to assist with their arboreal movement, the proboscis monkey has an extraordinary nose, while the snub-nosed monkeys have almost no nose at all. The male mandrills penis is red and the scrotum is lilac, the coloration is more pronounced in dominant males. Most Old World monkeys are at least partially omnivorous, but all prefer plant matter, the Barbary macaques diet consists mostly of leaves and roots, though it will also eat insects and uses cedar trees as a water source. Gestation in the Old World monkeys lasts between five and seven months, births are usually single, although, as with humans, twins occur from time to time. The young are born relatively well-developed, and are able to cling onto their mothers fur with their hands from birth, compared with most other mammals, they take a long time to reach sexual maturity, with four to six years being typical of most species. In most species, daughters remain with their mothers for life, males leave the group on reaching adolescence, and find a new troop to join. In many species, only an adult male lives with each group, driving off all rivals. Group sizes are variable, even within species, depending on the availability of food. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey
Old World monkey
Old World monkey
–
Paracolobus chemeroni fossil
Old World monkey
–
Black-footed gray langur, Semnopithecus hypoleucos
35.
Cladistically
–
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
Cladistically
–
Peter Chalmers Mitchell in 1920
Cladistically
–
Diagrammatic representation of the
divergence of modern
taxonomic groups from their
common ancestor
Cladistically
–
Robert John Tillyard
36.
Paraphyletic
–
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
Paraphyletic
–
The traditional class
Reptilia (green field) is a paraphyletic group comprising all
amniotes (Amniota) other than the mammals and birds. In contrast, the
clade Amniota itself is
monophyletic.
37.
Arboreal locomotion
–
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them, some animals may scale trees only occasionally, but others are exclusively arboreal. Furthermore, many of these principles may be applied to climbing without trees. The earliest known tetrapod with specializations that adapted it for climbing trees was Suminia, some invertebrate animals are exclusively arboreal in habitat, such as the tree snail. Arboreal habitats pose numerous mechanical challenges to animals moving in them and these challenges include moving on narrow branches, moving up and down inclines, balancing, crossing gaps, and dealing with obstructions. Moving along a narrow surface poses special difficulties to animals, additionally, foot placement is constrained by the need to make contact with the narrow branch. This narrowness severely restricts the range of movements and postures an animal can use to move, branches are frequently oriented at an angle to gravity in arboreal habitats, including being vertical, which poses special problems. As an animal moves up a branch, they must fight the force of gravity to raise their body. Conversely, as the animal descends, it must also fight gravity to control its descent and prevent falling, descent can be particularly problematic for many animals, and highly arboreal species often have specialized methods for controlling their descent. Due to the height of many branches and the disastrous consequences of a fall. On horizontal and gently sloped branches, the problem is tipping to the side due to the narrow base of support. The narrower the branch, the greater the difficulty in balancing a given animal faces, on steep and vertical branches, tipping becomes less of an issue, and pitching backwards or slipping downwards becomes the most likely failure. In this case, large-diameter branches pose a challenge, since the animal cannot place its forelimbs closer to the center of the branch than its hindlimbs. Branches are not continuous, and any arboreal animal must be able to move between gaps in the branches, or even between trees and this can be accomplished by reaching across gaps, by leaping across them or gliding between them. Arboreal habitats often contain many obstructions, both in the form of branches emerging from the one being moved on and other branches impinging on the space the animal needs to move through and these obstructions may impede locomotion, or may be used as additional contact points to enhance it. While obstructions tend to impede limbed animals, they benefit snakes by providing anchor points, arboreal organisms display many specializations for dealing with the mechanical challenges of moving through their habitats. Arboreal animals frequently have elongated limbs that help them cross gaps, reach fruit or other resources, test the firmness of support ahead, however, some species of lizard have reduced limb size that helps them avoid limb movement being obstructed by impinging branches. Many arboreal species, such as porcupines, chameleons, silky anteaters, spider monkeys
Arboreal locomotion
–
Leopards are good climbers and can carry their kills up their trees to keep them out of reach from scavengers and other predators.
Arboreal locomotion
–
Gibbons are very good brachiators because their elongated limbs enable them to easily swing and grasp on to branches.
Arboreal locomotion
–
The silky anteater uses its prehensile tail as a third arm for stabilization and balance, while its claws help better grasp and climb onto branches.
Arboreal locomotion
–
The gecko's toes adhere to surfaces via dry adhesion, to allow them to stay firmly attached to a branch or even a flat wall.
38.
Baboon
–
Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. The five species are some of the largest non-hominoid members of the order, only the mandrill. Previously, the closely related gelada and the two species of genus Mandrillus were grouped in the genus, and these Old World monkeys are still often referred to as baboons in everyday speech. They range in size and weight depending on species, the Guinea baboon is 50 cm and weighs only 14 kg, while the largest chacma baboon can be 120 cm and weigh 40 kg. Five species of Papio are commonly recognized, although there is disagreement about whether they are really full species or subspecies. They are P. ursinus, P. papio, P. hamadryas, P. anubis, many authors distinguish P. hamadryas as a full species, but regard all the others as subspecies of P. cynocephalus and refer to them collectively as savanna baboons. However, recent morphological and genetic studies of Papio show the hamadryas baboon to be closely related to the northern baboon species than to the southern species. In 2015 researchers found the oldest baboon fossil dating 2 million years ago, the traditional five-form classification probably under-represents the variation within Papio. However, current knowledge of the morphological, genetic, and behavioral diversity within Papio is too poor to make any final and these calluses are nerveless, hairless pads of skin that provide for the sitting comfort of the baboon. All baboon species exhibit pronounced sexual dimorphism, usually in size, males of the hamadryas baboon species also have large white manes. Baboons are terrestrial and are found in savannah, open woodland. Their diets are omnivorous, but mostly herbivorous, yet they eat insects and occasionally prey on fish, trout and salmon if available, shellfish, hares, birds, vervet monkeys and they are foragers and are active at irregular times throughout the day and night. They can raid human dwellings, and in South Africa, they have known to prey on sheep. Baboons in captivity have been known to live up to 45 years, baboons are able to acquire orthographic processing skills, which form part of the ability to read. Their principal predators are Nile crocodiles, lions, spotted and striped hyenas, leopards and they are considered a difficult prey for the leopard, though, which is mostly a threat to young baboons. Large males will often confront them by flashing their eyelids, showing their teeth by yawning, screeching, making gestures, although they are not a prey species, baboons have been killed by the black mamba. This usually occurs when a baboon accidentally rouses the snake, most baboons live in hierarchical troops. Group sizes vary between five and 250 animals, depending on circumstances, especially species and time of year
Baboon
Baboon
–
Face of a
hamadryas baboon (Papio hamadryas)
Baboon
–
Olive baboon with mother,
Lake Manyara National Park,
Tanzania
Baboon
–
Baboons caught up a tree by Kalahari lions (1 of 3)
39.
Diurnality
–
Diurnality is a form of plant or animal behavior characterized by activity during the day, with a period of sleeping, or other inactivity, at night. The common adjective used for daytime activity is diurnal, the timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a period, cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors. Animals active at dawn or dusk are crepuscular, those active at night are nocturnal, plants that open their flowers during the day are referred to as diurnal, while those that bloom at night are nocturnal. The timing of opening is often related to the time at which preferred pollinators are foraging. For example, sunflowers open during the day in order to attract bees, many animal species are diurnal, including many mammals, insects, reptiles and birds. In some animals, especially insects, external patterns of the environment control the activity, diurnality is descriptive, it refers to an observed 24-hour pattern, as opposed to ~24-hour circadian rhythms which are self-sustaining within the organism. In many species, the switches from nocturnal to diurnal foraging depending on the environmental temperature. This allows the individual to maximize its feeding efficiency during the summer and lower its risk of predation during the winter. Diurnal insects include some bees, such as Anthidium maculosum and these carder bees are diurnal and active only when the temperatures are above freezing. They are also most active when there are plenty of such as flowers, from which they can extract pollen. Some primarily nocturnal or crepuscular animals, like dogs and cats, have been domesticated and have become diurnal to coincide with the cycle of human life, however, these animals may exhibit their species original behavior when they are born feral. Other animals have been forced from their normal cycle to a one as a means of avoiding predators. Many plants are diurnal or nocturnal, depending on the period when the most effective pollinators, i. e. insects. Most angiosperm plants are visited by insects, so the flower adapts its phenology to the most effective pollinators. For example, the baobab is pollinated by bats and starts blooming in late afternoon. Services that alternate between high and low utilization in a daily cycle are described as being diurnal, many web sites have the most users during the day and little utilization at night, or vice versa. Operations planners can use this cycle to plan, for example, maintenance that needs to be done when there are fewer users on the web site
Diurnality
–
Ostriches are diurnal, but may be active on moonlit nights
40.
Primate cognition
–
Primate cognition is the study of the intellectual and behavioral skills of non-human primates, particularly in the fields of psychology, behavioral biology, primatology, and anthropology. Premack and Woodruffs 1978 article Does the chimpanzee have a theory of mind, was a contentious issue because of the problem of inferring from animal behavior the existence of thinking, of the existence of a concept of self or self-awareness, or of particular thoughts. For example, many researchers focus on understanding of intention, gaze, perspective. Recently, most non-human theory of research has focused on monkeys and great apes. There has been controversy over the interpretation of evidence purporting to show theory of mind ability—or inability—in animals. Two examples serve as demonstration, first, Povinelli et al and they found that the animals failed in most cases to differentially request food from the knower. Tomasello and like-minded colleagues who originally argued that great apes did not have theory of mind have since reversed their position, Povinelli and his colleagues, however, maintain that Tomasellos group has misinterpreted the results of their experiments. They point out that most evidence in support of great ape theory of mind involves naturalistic settings to which the apes may have already adapted through past learning and they therefore propose testing theory of mind abilities in great apes in novel, and not naturalistic settings. The modeling of human language in animals is known as animal language research, Nim Chimpsky, a chimpanzee, was successfully taught 125 signs during his life, though some disagree on whether this can be constituted as true language. There have been other, more successful animal language projects, such as Kanzi and Koko and it has been suggested that Nim Chimpskys limited success was due to short training sessions, rather than true language immersion. There are many reports of primates making or using tools, both in the wild or when captive, chimpanzees, orangutans, gorillas, capuchin monkeys, baboons, and mandrills have all been reported as using tools. The use of tools by primates is varied and includes hunting, collecting honey, processing food, collecting water, weapons, tool making is much rarer, but has been documented in orangutans, bonobos and bearded capuchin monkeys. Captive gorillas have made a variety of tools, in the wild, mandrills have been observed to clean their ears with modified tools. Scientists filmed a large male mandrill at Chester Zoo stripping down a twig, apparently to make it narrower, there is some controversy over whether tool use represents a higher level of physical cognition. Some studies suggest primates could use tools due to environmental or motivational clues, in 1913, Wolfgang Köhler started writing a book on problem solving titled The Mentality of Apes. In this research, Köhler observed the manner in which chimpanzees solve problems and he found that they stacked wooden crates to use as makeshift ladders in order to retrieve the food. If the bananas were placed on the ground outside of the cage, in the 1970s and the 1980s there had been suggestions that apes are unable to ask questions and to give negative answers. According to numerous published studies, apes are able to answer questions
Primate cognition
–
Tool use by a gorilla
41.
Lemur
–
Lemurs are a clade of strepsirrhine primates endemic to the island of Madagascar. As with other primates, such as lorises, pottos. In this regard, lemurs are often confused with ancestral primates, when in actuality, lemurs did not give rise to monkeys and apes, due to Madagascars highly seasonal climate, lemur evolution has produced a level of species diversity rivaling that of any other primate group. Until shortly after humans arrived on the island around 2,000 years ago, ranging in weight from the 30-gram mouse lemur to the 9-kilogram indri, lemurs share many common, basal primate traits, such as divergent digits on their hands and feet and nails instead of claws. However, their brain-to-body size ratio is smaller than that of anthropoid primates, lemurs are generally the most social of the strepsirrhine primates and communicate more with scents and vocalizations than with visual signals. Many lemur adaptations are in response to Madagascars highly seasonal environment, lemurs have relatively low basal metabolic rates and may exhibit seasonal breeding, dormancy, or female social dominance. Most eat a variety of fruits and leaves, while some are specialists. Although many share similar diets, different species of lemur share the same forests by differentiating niches, Lemur research during the 18th and 19th centuries focused on taxonomy and specimen collection. Although field observations trickled in from early explorers, modern studies of lemur ecology, initially hindered by political instability and turmoil on Madagascar during the mid-1970s, field studies resumed in the 1980s and have greatly increased the understanding of these primates. Research facilities like the Duke Lemur Center have provided research opportunities under more controlled settings, lemurs are important for research because their mix of ancestral characteristics and traits shared with anthropoid primates can yield insights on primate and human evolution. However, many species are threatened with extinction due to habitat loss. Although local traditions generally help protect lemurs and their forests, illegal logging, widespread poverty, Carl Linnaeus, the founder of modern binomial nomenclature, gave lemurs their name as early as 1758, when he used it in the 10th edition of Systema Naturae. He included three species under the genus Lemur, Lemur tardigradus, Lemur catta, and Lemur volans, although the term lemur was first intended for slender lorises, it was soon limited to the endemic Malagasy primates, which have been known as lemurs ever since. The name derives from the Latin term lemures, which refers to specters or ghosts that were exorcised during the Lemuria festival of ancient Rome, according to Linnaeus own explanation, the name was selected because of the nocturnal activity and slow movements of the slender loris. Being familiar with the works of Virgil and Ovid and seeing an analogy that fit with his naming scheme, Linnaeus adapted the term lemur for these nocturnal primates. However, Dunkel et al. noted in 2012 that it has been commonly and falsely assumed that Linnaeus was referring to the appearance, reflective eyes. Lemurs are primates belonging to the suborder Strepsirrhini, like other strepsirrhine primates, such as lorises, pottos, and galagos, they share ancestral traits with early primates. In this regard, lemurs are popularly confused with ancestral primates, however, lemurs did not give rise to monkeys, instead, they evolved independently in isolation on Madagascar
Lemur
Lemur
–
A life restoration of
Babakotia radofilai, a
sloth lemur that became extinct less than two thousand years ago
Lemur
–
Close-up of a
ruffed lemur 's foot, showing the
toilet-claw on the second toe and nails on all other toes
Lemur
–
A six-tooth version of the strepsirrhine
toothcomb in a
ring-tailed lemur, with canine-like premolars behind it
42.
Lorisidae
–
Lorisidae is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and include the lorises, Lorisids live in tropical, central Africa as well as in south and southeast Asia. Lorisids have a close, woolly fur, which is grey or brown. The eyes are large and face forward, the ears are small and often partially hidden in the fur. The thumbs are opposable and the finger is short. The second toe of the legs has a fine claw for grooming. Their tails are short or are missing completely and they grow to a length of 17 to 40 cm and a weight of between 0.3 and 2 kg, depending on the species. Their dental formula is similar to that of lemurs,2.1.3.32.1.3.3 Lorisids are nocturnal and arboreal, unlike the closely related galagos, lorisids never jump. Some have slow deliberate movements, whilst others can move with some speed across branches and it was previously thought that all lorisids moved slowly, but investigations using red light proved this to be wrong. Nonetheless, even the faster species freeze or move slowly if they hear or see any potential predator and this habit of remaining motionless whilst in danger is successful only because of the leafy environment of their jungle home, which helps to conceal their true position. With their strong hands they clasp at the branches and cannot be removed without significant force, most lorisids are solitary or live in small family groups. Slow lorises from southeast Asia produce a secretion from their brachial gland, the red slender loris from India also possesses brachial glands, but it is uncertain whether they also synthesize the toxin. The potto is thought to lack brachial glands, though it produces similar toxic excretions with its anal glands, the main diet of most lorisids consists of insects, but they also consume bird eggs and small vertebrates as well as fruits and sap. Lorisids have a period of four to six months and give birth to two young. These often clasp themselves to the belly of the mother or wait in nests, after three to nine months - depending on the species - they are weaned and are fully mature within 10 to 18 months. The life expectancy of lorises can be to up to 20 years, there are five genera and eleven species of lorisid. Nycticebus linglom Bornean slow loris, Nycticebus menagensis Pygmy slow loris, Nycticebus pygmaeus Family Galagidae, galagos Suborder Haplorrhini, tarsiers, monkeys and apes
Lorisidae
43.
Galago
–
Galagos /ɡəˈleɪɡoʊz/, also known as bushbabies, bush babies, or nagapies, are small nocturnal primates native to continental Africa, and make up the family Galagidae. They are sometimes included as a subfamily within the Lorisidae or Loridae, according to some accounts, the name bushbaby comes from either the animals cries or its appearance. The Afrikaans name nagapie is because they are almost exclusively seen at night, in both variety and abundance, the bushbabies are the most successful strepsirrhine primates in Africa, according to the African Wildlife Foundation. Galagos have large eyes give them good night vision, strong hind limbs, acute hearing. Their ears are bat-like and allow them to insects in the dark. They catch insects on the ground or snatch them out of the air, as they bound through the thick bushes, they fold their delicate ears back to protect them. They also fold them during rest and they have nails on most of their digits, except for the second toe of the hind foot, which bears a grooming claw. Their diet is a mixture of insects and other animals, fruit. After a few days, the mother carries the infant in her mouth, females may have singles, twins, or triplets, and may become very aggressive. Each newborn weighs less than half an ounce, for the first three days, the infant is kept in constant contact with the mother. The young are fed by the mother for six weeks and can feed themselves at two months, the young grow rapidly, often causing the mother to walk awkwardly as she transports them. Females maintain a territory, but share them with their offspring, males leave their mothers territories after puberty, but females remain, forming social groups consisting of closely related females and their young. Adult males maintain separate territories, which overlap with those of the social groups, generally. Males that have not established such territories sometimes form small bachelor groups, while keeping them as pets is not advised, it is certainly done. Equally, they are likely to attract attention from customs officials on importation into many countries. Reports from veterinary and zoological sources indicate captive lifetimes of 12.0 to 16.5 years, galagos communicate both by calling to each other, and by marking their paths with urine. By following the scent of urine, they can land on exactly the same every time. All species of galago produce species-specific loud calls or advertisement calls and these calls have multiple different functions
Galago
–
Galagos
Galago
–
Garnetts Galago, Otolemur garnettii
Galago
44.
Strepsirrhini
–
Collectively they are referred to as strepsirrhines. Adapiforms are sometimes referred to as being lemur-like, although the diversity of both lemurs and adapiforms does not support this comparison, today, Strepsirrhini excludes the tarsiers, which are now grouped in the other major primate suborder, Haplorhini, along with the monkeys and apes. Strepsirrhines are often referred to as living fossils. Instead, they have evolved for millions of years under natural selection, some of their traits may be derived from ancestral primates, while others are unique to strepsirrhines. Strepsirrhines are defined by their wet nose or rhinarium and they also have a smaller brain than comparably sized simians, large olfactory lobes for smell, a vomeronasal organ to detect pheromones, and a bicornuate uterus with an epitheliochorial placenta. Their eyes contain a layer to improve their night vision, and their eye sockets include a ring of bone around the eye. Strepsirrhine primates produce their own vitamin C, whereas haplorhine primates must obtain it from their diets, lemuriform primates are characterized by a toothcomb, a specialized set of teeth in the front, lower part of the mouth mostly used for combing fur during grooming. Often, the toothcomb is used to characterize all strepsirrhines. Instead, it is unique to lemuriforms and is not seen among adapiforms, lemuriforms groom orally, and also possess a grooming claw on the second toe of each foot for scratching in areas that are inaccessible to the mouth and tongue. It is unclear whether adapiforms possessed grooming claws, the taxonomy of strepsirrhines is controversial and has a complicated history. Strepsirrhines diverged from the haplorhine primates near the beginning of the primate radiation between 55 and 90 mya, older divergence dates are based on genetic analysis estimates, while younger dates are based on the scarce fossil record. Lemuriform primates may have evolved from either cercamoniines or sivaladapids, both of which were adapiforms that may have originated in Asia and they were once thought to have evolved from adapids, a more specialized and younger branch of adapiform primarily from Europe. Lemurs rafted from Africa to Madagascar between 47 and 54 mya, whereas the split from the African galagos around 40 mya. Both living and extinct strepsirrhines are behaviorally diverse, although all are primarily arboreal, most living lemuriforms are nocturnal, while most extinct adapiforms were diurnal. Both living and extinct groups primarily fed on fruit, leaves, many of todays strepsirrhines are endangered due to habitat destruction, hunting for bushmeat, and live capture for the exotic pet trade. The taxonomic name Strepsirrhini derives from the Greek στρεψίς and ῥινός, the name was first used by French naturalist Étienne Geoffroy Saint-Hilaire in 1812 as a subordinal rank comparable to Platyrrhini and Catarrhini. In his description, he mentioned Les narines terminales et sinueuses, following Pocock, many researchers continued to spell Strepsirrhini with a single r until primatologists Paulina Jenkins and Prue Napier pointed out the error in 1987. Strepsirrhines include the extinct adapiforms and the primates, which include lemurs
Strepsirrhini
Strepsirrhini
–
Early primates possessed adaptations for
arboreal locomotion that enabled maneuvering along fine branches, as seen in this
slender loris.
Strepsirrhini
–
Notharctus, a type of North American adapiform, resembled lemurs but it did not give rise to them.
Strepsirrhini
–
The suborder Strepsirrhini was proposed by
É. Geoffroy in 1812.
45.
Tarsier
–
Tarsiers are haplorrhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was more widespread, all the species living today are found in the islands of Southeast Asia. The fossil record indicates that their dentition has not changed much, except in size, within the family Tarsiidae, there are two extinct genera, Xanthorhysis and Afrotarsius. However, the placement of Afrotarsius is not certain, and it is listed in its own family, Afrotarsiidae, within the infraorder Tarsiiformes. So far, four species of tarsiers are known from the fossil record. Hesperotarsius thailandicus lived during the Early Miocene in northwestern Thailand, hesperotarsius sindhensis lived during the Miocene in Pakistan. Tarsius sirindhornae lived during the Middle Miocene in northern Thailand, the genus Tarsius has a longer fossil record than any other primate genus, but the assignment of the Eocene and Miocene fossils to the genus is questionable. Thus, some argue the debate is conclusively settled in favor of a monophyletic Haplorrhini. In common with simians, tarsiers have a mutation in the L-gulonolactone oxidase gene, which confers the need for vitamin C in the diet. At a lower level, the tarsiers have, until recently, all been placed in the genus Tarsius. Species level taxonomy is complex, with often being of limited use compared to vocalizations. Further confusion existed over the validity of certain names, among others, the widely used T. dianae has been shown to be a junior synonym of T. dentatus, and comparably, T. spectrum is now considered a junior synonym of T. tarsier. In 2010, Colin Groves and Myron Shekelle suggested splitting the genus Tarsius into three genera, the Philippine tarsiers, the tarsiers, and the eastern tarsiers. This was based on differences in dentition, eye size, limb and hand length, tail tufts, tail sitting pads, the number of mammae, chromosome count, socioecology, vocalizations, and distribution. The senior taxon of the species, T. tarsier was restricted to the population of a Selayar island, in 2014, scientists from the University of the Philippines - Institute of Biology in partnership with the University of Kansas has discovered a gentically distinct populations of Philippine tarsier. The genetically distinct populations are found in the Dinagat Islands, Surigao del Norte, isolation is the key to the populations distinctiveness. However the new research found the relationships among the Philippine tarsier populations was even messier. For the purposes of the paper, the scientists refer to this as the Dinagat-Caraga tarsier, infraorder Tarsiiformes Family Tarsiidae, tarsiers Genus Carlito Philippine tarsier, Carlito syrichta C. s. syrichta C. s. fraterculus C. s. carbonarius C. s
Tarsier
Tarsier
–
Philippine tarsier (Carlito syrichta), one of the smallest primates.
Tarsier
–
Tarsier tree climbing
46.
Gibbon
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Gibbons are apes in the family Hylobatidae. The family historically contained one genus, but now is split into four genera and 18 species, gibbons occur in tropical and subtropical rainforests from eastern Bangladesh and northeast India to southern China and Indonesia. Also called the smaller apes or lesser apes, gibbons differ from great apes in being smaller, exhibiting low sexual dimorphism, in certain anatomical details, they superficially more closely resemble monkeys than great apes do, but like all apes, gibbons are tailless. Gibbons also display pair-bonding, maintaining the same mate for life, gibbons are masters of their primary mode of locomotion, brachiation, swinging from branch to branch for distances up to 15 m, at speeds as high as 55 km/h. They can also make leaps up to 8 m, and walk bipedally with their arms raised for balance and they are the fastest and most agile of all tree-dwelling, nonflying mammals. Depending on species and sex, gibbons fur coloration varies from dark to light brown shades, Gibbon species include the siamang, the white-handed or lar gibbon, and the hoolock gibbons. Whole genome molecular dating analyses indicate that the gibbon lineage diverged from that of great apes around 16.8 million years ago, adaptive divergence associated with chromosomal rearrangements led to rapid radiation of the four genera 5-7 Mya. Whole genome analysis suggests divergence of Hylobates pileatus from Hylobates moloch 1. 5-3.0 Mya, the extinct Bunopithecus sericus is a gibbon or gibbon-like ape which, until recently, was thought to be closely related to the hoolock gibbons. The family is divided into four genera based on their diploid chromosome number, Hylobates, Hoolock, Nomascus and these morphological ambiguities have led to hybrids in zoos. Interspecific hybrids, hybrids within a genus, are suspected to occur in wild gibbons where their ranges overlap. However, no records exist of fertile hybrids between different gibbon genera, either in the wild or in captivity, one unique aspect of a gibbons anatomy is the wrist, which functions something like a ball and socket joint, allowing for biaxial movement. This greatly reduces the amount of energy needed in the arm and torso. Gibbons also have long hands and feet, with a cleft between the first and second digits of their hands. Their fur is black, gray, or brownish, often with white markings on hands, feet. Some species have a throat sac, which inflates and serves as a resonating chamber when the animals call. This structure can become large in some species, sometimes equaling the size of the animals head. Their voices are more powerful than that of any human singer. Gibbon skulls and teeth resemble those of the apes
Gibbon
Gibbon
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Agile gibbon,
Hylobates agilis
Gibbon
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Siamang,
Symphalangus syndactylus
Gibbon
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Northern white-cheeked gibbon,
Nomascus leucogenys
47.
Orangutan
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The orangutans are the two exclusively Asian species of extant great apes. Native to Indonesia and Malaysia, orangutans are found in only the rainforests of Borneo. Classified in the genus Pongo, orangutans were considered to be one species, since 1996, they have been divided into two species, the Bornean orangutan and the Sumatran orangutan. In addition, the Bornean species is divided three subspecies. Based on genome sequencing, the two extant orangutan species evidently diverged around 400,000 years ago, the ancestors of the Ponginae subfamily split from the main ape line in Africa 16 to 19 million years ago and spread into Asia. Orangutans are the most arboreal of the apes and spend most of their time in trees. Their hair is typically reddish-brown, instead of the brown or black hair typical of chimpanzees, males and females differ in size and appearance. Dominant adult males have distinctive cheek pads and produce long calls that attract females, younger males do not have these characteristics and resemble adult females. Orangutans are the most solitary of the apes, with social bonds occurring primarily between mothers and their dependent offspring, who stay together for the first two years. Fruit is the most important component of a diet, however. They can live over 30 years in both the wild and captivity, orangutans are among the most intelligent primates, they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage. The apes have been studied for their learning abilities. There may even be distinctive cultures within populations, field studies of the apes were pioneered by primatologist Birutė Galdikas. Both orangutan species are considered to be critically endangered, human activities have caused severe declines in the populations and ranges of both species. Threats to wild populations include poaching, habitat destruction. Several conservation and rehabilitation organisations are dedicated to the survival of orangutans in the wild, the name orangutan is derived from the Malay and Indonesian words orang meaning person and hutan meaning forest, thus person of the forest. Orang Hutan was originally not used to refer to apes, the Malay words used to refer specifically to the ape are maias and mawas, but it is unclear if those words refer to just orangutans, or to all apes in general. The word appeared in several German-language descriptions of Indonesian zoology in the 17th century, the likely origin of the word comes specifically from the Banjarese variety of Malay
Orangutan
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Orangutans
Orangutan
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The orangutan's skeleton is adapted for its arboreal lifestyle.
Orangutan
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Although orangutans may consume leaves, shoots, and even bird eggs, fruit is the most important part of their diet.
Orangutan
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Orangutans are the least social of the great apes, but individuals do commonly interact.
48.
Gorilla
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Gorillas are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. The eponymous genus Gorilla is divided into two species, the gorillas and the western gorillas, and either four or five subspecies. They are the largest living primates, the DNA of gorillas is highly similar to that of humans, from 95–99% depending on what is counted, and they are the next closest living relatives to humans after the chimpanzees and bonobos. Gorillas natural habitats cover tropical or subtropical forests in Africa, although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. The mountain gorilla inhabits the Albertine Rift montane cloud forests of the Virunga Volcanoes, ranging in altitude from 2, 200–4,300 metres. The word gorilla comes from the history of Hanno the Navigator, members of the expedition encountered a savage people, the greater part of whom were women, whose bodies were hairy, and who our interpreters called Gorillae. The word was later used as the species name, though it is unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys. The American physician and missionary Thomas Staughton Savage and naturalist Jeffries Wyman first described the gorilla in 1847 from specimens obtained in Liberia. The name was derived from Ancient Greek Γόριλλαι, meaning tribe of hairy women, the closest relatives of gorillas are the other two Homininae species, chimpanzees and humans, all of them having diverged from a common ancestor about 7 million years ago. Human gene sequences differ only 1. 6% on average from the sequences of corresponding gorilla genes, until recently, gorillas were considered to be a single species, with three subspecies, the western lowland gorilla, the eastern lowland gorilla and the mountain gorilla. There is now agreement that there are two species, each with two subspecies, more recently, a third subspecies has been claimed to exist in one of the species. The separate species and subspecies developed from a type of gorilla during the Ice Age. Primatologists continue to explore the relationships between various gorilla populations, the species and subspecies listed here are the ones upon which most scientists agree. The proposed third subspecies of Gorilla beringei, which has not yet received a trinomen, is the Bwindi population of the mountain gorilla, some variations that distinguish the classifications of gorilla include varying density, size, hair colour, length, culture, and facial widths. Now, over 100,000 western lowland gorillas are thought to exist in the wild, with 4,000 in zoos, mountain gorillas are the most severely endangered, with an estimated population of about 880 left in the wild and none in zoos. Population genetics of the lowland gorillas suggest that the western and eastern lowland populations diverged ~261 thousand years ago, gorillas move around by knuckle-walking, although they sometimes walk bipedally for short distances while carrying food or in defensive situations. Wild male gorillas weigh 135 to 180 kg while females usually weigh half as much as adult males at 70–115 kg. Adult males are 1.7 to 1.8 m tall, female gorillas are shorter, with smaller arm spans
Gorilla
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Gorillas
Gorilla
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A skull of a gorilla
Gorilla
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Young gorilla in tree
Gorilla
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Gorilla night nest constructed in a tree.
49.
Chimpanzee
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Chimpanzees are one of the two species of the genus Pan, the other being the bonobo. Together with gorillas, they are the only exclusively African species of ape that are currently extant. Native to sub-Saharan Africa, both chimpanzees and bonobos are found in the Congo jungle. In addition, P. troglodytes is divided into four subspecies, based on genome sequencing, the two extant Pan species diverged around one million years ago. The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful and their hair is typically black or brown. Males and females differ in size and appearance, both chimps and bonobos are some of the most social great apes, with social bonds occurring among individuals in large communities. Fruit is the most important component of a diet, however, they will also eat vegetation, bark, honey, insects. They can live over 30 years in both the wild and captivity, Chimpanzees and bonobos are equally humanitys closest living relatives. As such, they are among the largest-brained, and most intelligent of primates, they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and they have both been extensively studied for their learning abilities. There may even be distinctive cultures within populations, field studies of Pan troglodytes were pioneered by primatologist Jane Goodall. Both Pan species are considered to be endangered as human activities have caused declines in the populations. Threats to wild populations include poaching, habitat destruction. Several conservation and rehabilitation organisations are dedicated to the survival of Pan species in the wild, the first use of the name chimpanze is recorded in The London Magazine in 1738, glossed as meaning mockman in a language of the Angolans. The spelling chimpanzee is found in a 1758 supplement to Chambers Cyclopædia, the colloquialism chimp was most likely coined some time in the late 1870s. The common chimpanzee was named Simia troglodytes by Johann Friedrich Blumenbach in 1776, the species name troglodytes is a reference to the Troglodytae, an African people described by Greco-Roman geographers. Blumenbach first used it in his De generis humani varietate nativa liber in 1776, the genus name Pan was first introduced by Lorenz Oken in 1816. An alternative Theranthropus was suggested by Brookes 1828 and Chimpansee by Voigt 1831, troglodytes was not available, as it had been given as the name of a genus of wren in 1809. The International Commission on Zoological Nomenclature adopted Pan as the official name of the genus in 1895
Chimpanzee
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Chimpanzees Temporal range: Middle
Pliocene - Recent
Chimpanzee
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Bonobo
Chimpanzee
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Common chimpanzees in
Gombe Stream National Park
Chimpanzee
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Common chimpanzee using a stick
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