fbpx
Wikipedia

Phanerozoic

The Phanerozoic Eon[4] is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 538.8 million years ago to the present,[5] and it began with the Cambrian Period, when animals first developed hard shells preserved in the fossil record. The time before the Phanerozoic, called the Precambrian, is now divided into the Hadean, Archaean and Proterozoic eons.

Phanerozoic
538.8 ± 0.2 – 0 Ma
Fauna and flora from each of the twelve periods of the Phanerozoic. From top left: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, and Quaternary species.
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEon
Stratigraphic unitEonothem
First proposed byGeorge Halcott Chadwick, 1930
Time span formalityFormal
Lower boundary definitionAppearance of the Ichnofossil Treptichnus pedum
Lower boundary GSSPFortune Head section, Newfoundland, Canada
47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W / 47.0762; -55.8310
Lower GSSP ratified1992
Upper boundary definitionN/A
Upper boundary GSSPN/A
Upper GSSP ratifiedN/A

The time span of the Phanerozoic starts with the sudden appearance of fossilised evidence of a number of animal phyla; the evolution of those phyla into diverse forms; the emergence and development of complex plants; the evolution of fish; the emergence of insects and tetrapods; and the development of modern fauna. Plant life on land appeared in the early Phanerozoic eon. During this time span, tectonic forces which move the continents had collected them into a single landmass known as Pangaea (the most recent supercontinent), which then separated into the current continental landmasses.

Etymology

The term Phanerozoic derives from the Ancient Greek words φανερός (phanerós), meaning visible, and ζωή (zōḗ), meaning life; since it was once believed that life began in the Cambrian, the first period of this eon. The term "Phanerozoic" was coined in 1930 by the American geologist George Halcott Chadwick (1876–1953).[6][7]

Proterozoic-Phanerozoic boundary

The Proterozoic-Phanerozoic boundary is at 538.8 million years ago.[5] In the 19th century, the boundary was set at time of appearance of the first abundant animal (metazoan) fossils but several hundred groups (taxa) of metazoa of the preceding Proterozoic eon have been identified since the systematic study of those forms started in the 1950s.[8][9]

Eras of the Phanerozoic

The Phanerozoic is divided into three eras: the Paleozoic, Mesozoic, and Cenozoic, which are further subdivided into 12 periods. The Paleozoic features the evolution of fish, amphibians and reptiles. The Mesozoic features the evolution of lizards, crocodiles, snakes, turtles, mammals, and dinosaurs (including birds). The Cenozoic begins with the extinction of the non-avian dinosaurs, and features evolution of great diversity in birds and mammals. Humans appeared and evolved during the most recent part of the Cenozoic.

Paleozoic Era

The Paleozoic is a time in Earth's history when complex life forms evolved, took their first breath of oxygen on dry land, and when the forerunners of all multicelular life on Earth began to diversify. There are six periods in the Paleozoic era: Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.[10]

Cambrian Period

The Cambrian is the first period of the Paleozoic Era and ran from 539 million to 485 million years ago. The Cambrian sparked a rapid expansion in the diversity of animals, in an event known as the Cambrian explosion, during which the greatest number of animal body plans evolved in a single period in the history of Earth. Complex algae evolved, and the fauna was dominated by armoured arthropods, such as trilobites. Almost all phyla of marine animals evolved in this period. During this time, the super-continent Pannotia began to break up, most of which later recombined into the super-continent Gondwana.[11]

Ordovician Period

The Ordovician spans from 485 million to 444 million years ago. The Ordovician was a time in Earth's history in which many groups still prevalent today evolved or diversified, such as primitive cephalopods, fish, and corals. This process is known as the Great Ordovician Biodiversification Event, or GOBE. Trilobites began to be replaced by articulate brachiopods, and crinoids also became an increasingly important part of the fauna.[12] The first arthropods crept ashore to colonise Gondwana, a continent empty of animal life. By the end of the Ordovician, Gondwana had moved from the equator to the South Pole, and Laurentia had collided with Baltica, closing the Iapetus Ocean. The glaciation of Gondwana resulted in a major drop in sea level, killing off all life that had established along its coast. Glaciation caused an icehouse Earth, leading to the Ordovician–Silurian extinction, during which 60% of marine invertebrates and 25% of families became extinct. Though one of the deadliest mass extinctions in earth's history, the O–S extinction did not cause profound ecological changes between the periods.[13]

Silurian Period

 
Dalmanites limulurus, a species of Silurian trilobites

The Silurian spans from 444 million to 419 million years ago, which saw a warming from an icehouse Earth. This period saw the mass evolution of fish, as jawless fish became more numerous, and early jawed and freshwater fish appeared in the fossil record. Arthropods remained abundant, and some groups, such as eurypterids, became apex predators. Fully terrestrial life established itself on land, including early arachnids, fungi, and myriapods (many-legged arthropods). The evolution of vascular plants such as Cooksonia allowed plants to gain a foothold on land as well. These early terrestrial plants are the forerunners of all plant life on land. During this time, there were four continents: Gondwana (Africa, South America, Australia, Antarctica, India), Laurentia (North America with parts of Europe), Baltica (the rest of Europe), and Siberia (Northern Asia).[14]

Devonian Period

 
Cephalaspis, a jawless fish

The Devonian spans from 419 million to 359 million years ago. Also informally known as the "Age of the Fish", the Devonian features a huge diversification in fish. Armored fish included jawless "agnathans", as well as jawed placoderms such as Dunkleosteus. The Devonian also saw a diversification of modern fish groups such as chondricthyans (sharks and kin), osteichthyans (ray-finned fish), and sarcopterygians (lobe-finned fish). One lineage of sarcopterygians evolved into the first four-limbed vertebrates, which would eventually become tetrapods. On land, plant groups diversified; the first trees and seeds evolved during this period. By the Middle Devonian, shrub-like forests of early plants existed: lycophytes, horsetails, ferns, and progymnosperm. This event also allowed the diversification of arthropod life as they took advantage of the new habitat. Near the end of the Devonian, 70% of all species became extinct in a sequence of mass extinction events, collectively known as the Late Devonian extinction.[15]

Carboniferous Period

 
Proterogyrinus, a Carboniferous amphibian (non-amniote tetrapod)

The Carboniferous spans from 359 million to 299 million years ago.[16] Tropical swamps dominated the Earth, and the large amounts of trees created much of the carbon that became coal deposits (hence the name Carboniferous). About 90% of all coal beds were deposited in the Carboniferous and Permian periods, which represent just 2% of the Earth's geologic history.[17] The high oxygen levels caused by these swamps allowed massive arthropods, normally limited in size by their respiratory systems, to proliferate. Tetrapods diversified during the Carboniferous, and one lineage acquired an amniotic egg which could survive outside of the water. These tetrapods, the amniotes, included the first reptiles and synapsids (mammal relatives). Throughout the Carboniferous, there was a cooling pattern, which eventually led to the glaciation of Gondwana as much of it was situated around the south pole. This event was known as the Permo-Carboniferous Glaciation and resulted in a major loss of area for coal forests, the Carboniferous rainforest collapse.[18]

Permian Period

 
Dimetrodon grandis, a synapsid from the early Permian

The Permian spans from 298 million to 251 million years ago and was the last period of the Paleozoic era. At its beginning, all continents came together to form the super-continent Pangaea, surrounded by one ocean called Panthalassa. The Earth was relatively dry compared to the Carboniferous, with harsh seasons, as the climate of the interior of Pangaea was not moderated by large bodies of water. Amniotes flourished and diversified in the new dry climate, particularly synapsids such as Dimetrodon, Edaphosaurus, and the ancestors of modern mammals. The first conifers evolved during this period, then dominated the terrestrial landscape. The Permian ended with at least one mass extinction, the Permian-Triassic mass extinction, an event sometimes known as "the Great Dying". This extinction was the largest in earth's history and led to the loss of 95% of all species of life.[19][20]

Mesozoic Era

The Mesozoic ranges from 252 million to 66 million years ago. Also referred to as the Age of Reptiles or Age of Conifers,[21] the Mesozoic featured the appearance of many modern tetrapods, as reptiles ascended to ecological dominance over synapsids. The Mesozoic is subdivided into three periods: the Triassic, Jurassic, and Cretaceous.

Triassic Period

The Triassic ranges from 252 million to 201 million years ago. The Triassic is a transitional time in Earth's history between the Permian Extinction and the lush Jurassic Period. It has three major epochs: Early Triassic, Middle Triassic. and Late Triassic.[22]

The Early Triassic lasted between 252 million to 247 million years ago,[23] and was a hot and arid epoch in the aftermath of the Permian Extinction. Many tetrapods during this epoch represented a disaster fauna, a group of animals with low diversity and cosmopolitanism (wide geographic ranges).[24] Temnospondyli recovered and rediversified into large aquatic predators during the Triassic.[25][26] Reptiles also diversified rapidly, with aquatic reptiles such as ichthyosaurs and sauropterygians proliferating in the seas. On land, the first true archosaurs appeared, including pseudosuchians (crocodile relatives) and avemetatarsalians (bird/dinosaur relatives).

 
Plateosaurus, an early sauropodomorph dinosaur

The Middle Triassic spans from 247 million to 237 million years ago.[23] The Middle Triassic featured the beginnings of the break-up of Pangaea as rifting commenced in north Pangaea. The northern part of the Tethys Ocean, the Paleotethys Ocean, had become a passive basin, but a spreading center was active in the southern part of the Tethys Ocean, the Neotethys Ocean.[27] Phytoplankton, coral, crustaceans, and many other invertebrates recovered from the Permian extinction by the end of the Middle Triassic.[28] Meanwhile, on land, reptiles continued to diversify, conifer forests flourished,[29] as well as the first flies.[30][31][32]

The Late Triassic spans from 237 million to 201 million years ago.[23] Following the bloom of the Middle Triassic, the Late Triassic was warm and arid, with a strong monsoon climate and with most precipitation limited to coastal regions and high latitudes.[33] The first true dinosaurs appeared early in the Late Triassic,[34] and pterosaurs evolved a bit later.[35][36][37] Other large reptilian competitors to the dinosaurs were wiped out by the Triassic–Jurassic extinction event, in which most archosaurs (excluding crocodylomorphs, pterosaurs, and dinosaurs), many synapsids, and almost all large amphibians became extinct, as well as 34% of marine life in the fourth mass extinction event. The cause of the extinction is debated, but likely resulted from eruptions of the CAMP large igneous province.[38]

Jurassic Period

 
Sericipterus, a pterosaur

The Jurassic ranges from 201 million to 145 million years ago, and features three major epochs: Early Jurassic, Middle Jurassic, and Late Jurassic.[39]

The Early Jurassic Epoch spans from 201 million to 174 million years ago.[39] The climate was much more humid than during the Triassic, and as a result, the world was warm and partially tropical,[40][41] though possibly with short colder intervals.[42] Plesiosaurs, ichthyosaurs and ammonites dominated the seas,[43] while dinosaurs and other reptiles dominated the land,[43] with species such as Dilophosaurus at the apex.[44] Crocodylomorphs evolved into aquatic forms, pushing the large amphibians to near extinction.[45][43] True mammals were present during the Jurassic[46] but remained small, with average body masses of less than 10 kilograms (22 lb) until the end of the Cretaceous.[47][48]

 
Stegosaurus, a large ornithischian dinosaur from the Late Jurassic

The Middle and Late Jurassic Epochs span from 174 million to 145 million years ago.[39] Conifer savannahs made up a large portion of the world's forests.[49][50] In the oceans, plesiosaurs were quite common, and ichthyosaurs were flourishing.[51] The Late Jurassic Epoch spans from 163 million to 145 million years ago.[39] The Late Jurassic featured a severe extinction of sauropods in northern continents, alongside many ichthyosaurs. However, the Jurassic-Cretaceous boundary did not strongly impact most forms of life.[52]

Cretaceous Period

The Cretaceous is the Phanerozoic's longest period, and the last period of the Mesozoic. It spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous, and Late Cretaceous.[53]

 
Tylosaurus, a type of large marine lizards known as mosasaurs

The Early Cretaceous Epoch spans from 145 million to 100 million years ago.[53] Dinosaurs continued to be abundant, with groups such as tyrannosauroids, avialans (birds), marginocephalians, and ornithopods seeing early glimpses of later success. Other tetrapods, such as stegosaurs and ichthyosaurs, declined significantly, and sauropods were restricted to southern continents.

The Late Cretaceous Epoch spans from 100 million to 66 million years ago.[53] The Late Cretaceous featured a cooling trend that would continue into the Cenozoic Era. Eventually, the tropical climate was restricted to the equator and areas beyond the tropic lines featured more seasonal climates. Dinosaurs still thrived as new species such as Tyrannosaurus, Ankylosaurus, Triceratops and hadrosaurs dominated the food web. Whether or not pterosaurs went into a decline as birds radiated is debated; however, many families survived until the end of the Cretaceous, alongside new forms such as the gigantic Quetzalcoatlus.[54] Mammals diversified despite their small sizes, with metatherians (marsupials and kin) and eutherians (placentals and kin) coming into their own. In the oceans, mosasaurs diversified to fill the role of the now-extinct ichthyosaurs, alongside huge plesiosaurs such as Elasmosaurus. Also, the first flowering plants evolved. At the end of the Cretaceous, the Deccan Traps and other volcanic eruptions were poisoning the atmosphere. As this was continued, it is thought that a large meteor smashed into Earth, creating the Chicxulub Crater and the event known as the K–Pg extinction, the fifth and most recent mass extinction event, during which 75% of life on Earth became extinct, including all non-avian dinosaurs. Every living thing with a body mass over 10 kilograms became extinct, and the age of the dinosaurs came to an end.[55][56]

Cenozoic Era

The Cenozoic featured the rise of mammals as the dominant class of animals, as the end of the age of the dinosaurs left significant open niches. There are three divisions of the Cenozoic: Paleogene, Neogene and Quaternary.

Paleogene Period

The Paleogene spans from the extinction of the non-avian dinosaurs, some 66 million years ago, to the dawn of the Neogene 23 million years ago. It features three epochs: Paleocene, Eocene and Oligocene.

 
Basilosaurus was an early cetacean, related to modern whales

The Paleocene Epoch began with the K–Pg extinction event, and the early part of the Paleocene saw the recovery of the Earth from that event. The continents began to take their modern shapes, but most continents (and India) remained separated from each other: Africa and Eurasia were separated by the Tethys Sea, and the Americas were separated by the strait of Panama, as the Isthmus of Panama had not yet formed. This epoch featured a general warming trend, and the earliest modern jungles expanded, eventually reaching the poles. The oceans were dominated by sharks, as the large reptiles that had once ruled had become extinct. Mammals diversified rapidly, but most remained small. The largest tetrapod carnivores during the Paleocene were reptiles, including crocodyliforms, choristoderans, and snakes. Titanoboa, the largest known snake, lived in South America during the Paleocene.

The Eocene Epoch ranged from 56 million to 34 million years ago. In the early Eocene, most land mammals were small and living in cramped jungles, much like the Paleocene. Among them were early primates, whales and horses along with many other early forms of mammals. The climate was warm and humid, with little temperature gradient from pole to pole. In the Middle Eocene Epoch, the circum-Antarctic current between Australia and Antarctica formed, disrupting ocean currents worldwide, resulting in global cooling, and causing the jungles to shrink. More modern forms of mammals continued to diversify with the cooling climate even as more archaic forms died out. By the end of the Eocene, whales such as Basilosaurus had become fully aquatic. The late Eocene Epoch saw the rebirth of seasons, which caused the expansion of savanna-like areas with the earliest substantial grasslands.[57][58] At the transition between the Eocene and Oligocene epochs there was a significant extinction event, the cause of which is debated.

The Oligocene Epoch spans from 34 million to 23 million years ago. The Oligocene was an important transitional period between the tropical world of the Eocene and more modern ecosystems. This period featured a global expansion of grass which led to many new species taking advantage, including the first elephants, cats, dogs, marsupials and many other species still prevalent today. Many other species of plants evolved during this epoch also, such as the evergreen trees. The long term cooling continued and seasonal rain patterns established. Mammals continued to grow larger. Paraceratherium, one of the largest land mammals to ever live, evolved during this epoch, along with many other perissodactyls.

Neogene Period

The Neogene spans from 23.03 million to 2.58 million years ago. It features two epochs: the Miocene and the Pliocene.[59]

The Miocene spans from 23.03 million to 5.333 million years ago and is a period in which grass spread further across, effectively dominating a large portion of the world, diminishing forests in the process. Kelp forests evolved, leading to the evolution of new species, such as sea otters. During this time, perissodactyls thrived, and evolved into many different varieties. Alongside them were the apes, which evolved into 30 species. Overall, arid and mountainous land dominated most of the world, as did grazers. The Tethys Sea finally closed with the creation of the Arabian Peninsula and in its wake left the Black, Red, Mediterranean and Caspian Seas. This only increased aridity. Many new plants evolved, and 95% of modern seed plants evolved in the mid-Miocene.[60]

The Pliocene lasted from 5.333 million to 2.58 million years ago. The Pliocene featured dramatic climatic changes, which ultimately led to modern species and plants. The Mediterranean Sea dried up for hundreds of thousand years in the Messinian salinity crisis. Along with these major geological events, Africa saw the appearance of Australopithecus, the ancestor of Homo. The isthmus of Panama formed, and animals migrated between North and South America, wreaking havoc on the local ecology. Climatic changes brought savannas that are still continuing to spread across the world, Indian monsoons, deserts in East Asia, and the beginnings of the Sahara desert. The Earth's continents and seas moved into their present shapes. The world map has not changed much since, save for changes brought about by the glaciations of the Quaternary, such as the Great Lakes.[61][62]

Quaternary Period

 
Megafauna of the Pleistocene (mammoths, cave lions, woolly rhinos, reindeer, horses)

The Quaternary spans from 2.58 million years ago to present day, and is the shortest geological period in the Phanerozoic Eon. It features modern animals, and dramatic changes in the climate. It is divided into two epochs: the Pleistocene and the Holocene.

The Pleistocene lasted from 2.58 million to 11,700 years ago. This epoch was marked by a series of glacial periods (ice ages) as a result of the cooling trend that started in the Mid-Eocene. There were numerous separate glaciation periods marked by the advance of ice caps as far south as 40 degrees N latitude in mountainous areas. Meanwhile, Africa experienced a trend of desiccation which resulted in the creation of the Sahara, Namib, and Kalahari deserts. Mammoths, giant ground sloths, dire wolves, sabre-toothed cats, and humans were common and widespread during the Pleistocene. As the Pleistocene drew to a close, a major extinction wiped out much of the world's megafauna, including non-Homo sapiens human species such as Homo neanderthalensis. All the continents were affected, but Africa was impacted to a lesser extent. That continent retained many large animals, such as elephants, rhinos, and hippos. The extent to which Homo Sapiens were involved in this extinction is debated.[63]

The Holocene began 11,700 years ago and lasts until the present day. All recorded history and "Human history" lies within the boundaries of the Holocene epoch.[64] Human activity is blamed for an ongoing mass extinction that began roughly 10,000 years ago, though the species becoming extinct have only been recorded since the Industrial Revolution. This is sometimes referred to as the "Sixth Extinction". Hundreds of species have become extinct due to human activity since the Industrial Revolution.[65][66]

Biodiversity

 
During the Phanerozoic, biodiversity shows an overall but not monotonic increase from near zero to several thousands of genera

It has been demonstrated that changes in biodiversity through the Phanerozoic correlate much better with the hyperbolic model (widely used in demography and macrosociology) than with exponential and logistic models (traditionally used in population biology and extensively applied to fossil biodiversity as well). The latter models imply that changes in diversity are guided by a first-order positive feedback (more ancestors, more descendants) or a negative feedback that arises from resource limitation, or both. The hyperbolic model implies a second-order positive feedback. The hyperbolic pattern of the human population growth arises from quadratic positive feedback, caused by the interaction of the population size and the rate of technological growth.[67] The character of biodiversity growth in the Phanerozoic Eon can be similarly accounted for by a feedback between the diversity and community structure complexity. It has been suggested that the similarity between the curves of biodiversity and human population probably comes from the fact that both are derived from the superposition on the hyperbolic trend of cyclical and random dynamics.[67]

See also

 
Global map reconstruction showing continents at 500 million years ago
 
Global maps showing continental movement from 250 million years ago to present day.

Citations

  1. ^ . Lexico UK English Dictionary. Oxford University Press. Archived from the original on 6 August 2020.
  2. ^ "Phanerozoic". Merriam-Webster Dictionary.
  3. ^ "Phanerozoic". Dictionary.com Unabridged (Online). n.d.
  4. ^ There are several ways of pronouncing Phanerozoic, including /ˌfænərəˈz.ɪk, ˌfænrə-, -r-/ FAN-ər-ə-ZOH-ik, FAN-rə-, -⁠roh-.[1][2][3]
  5. ^ a b "Stratigraphic Chart 2022" (PDF). International Stratigraphic Commission. February 2022. Retrieved 20 April 2022.
  6. ^ Chadwick, G.H. (1930). "Subdivision of geologic time". Bulletin of the Geological Society of America. 41: 47–48.
  7. ^ Harland, B.; et al., eds. (1990). A geologic timescale 1989. Cambridge: Cambridge University Press. p. 30. ISBN 0-521-38361-7.
  8. ^ Glaessner, Martin F. (1961). "Precambrian Animals". Scientific American. 204 (3): 72–78. Bibcode:1961SciAm.204c..72G. doi:10.1038/scientificamerican0361-72.
  9. ^ Geyer, Gerd; Landing, Ed (2017). "The Precambrian–Phanerozoic and Ediacaran–Cambrian boundaries: a historical approach to a dilemma". Geological Society, London, Special Publications. 448 (1): 311–349. Bibcode:2017GSLSP.448..311G. doi:10.1144/SP448.10. S2CID 133538050.
  10. ^ University of California. "Paleozoic". University of California. from the original on 2 May 2015.
  11. ^ University of California. "Cambrian". University of California. from the original on 15 May 2012.
  12. ^ Cooper, John D.; Miller, Richard H.; Patterson, Jacqueline (1986). A Trip Through Time: Principles of Historical Geology. Columbus: Merrill Publishing Company. pp. 247, 255–259. ISBN 978-0-675-20140-7.
  13. ^ University of California. "Ordovician". University of California. from the original on 2 May 2015.
  14. ^ University of California. "Silurian". University of California. from the original on 16 June 2017.
  15. ^ University of California. "Devonian". University of California. from the original on 11 May 2012.
  16. ^ Monte Hieb. "Carboniferous Era". unknown. from the original on 20 December 2014.
  17. ^ McGhee, George R. (2018). Carboniferous giants and mass extinction : the late Paleozoic Ice Age world. New York: Columbia University Press. p. 98. ISBN 9780231180979.
  18. ^ University of California. "Carboniferous". University of California. from the original on 10 February 2012.
  19. ^ Natural History Museum. "The Great Dying". Natural History Museum. from the original on 20 April 2015.
  20. ^ University of California. "Permian Era". University of California. from the original on 4 July 2017.
  21. ^ Dean, Dennis R. (1999). Gideon Mantell and the Discovery of Dinosaurs. Cambridge University Press. pp. 97–98. ISBN 978-0521420488.
  22. ^ Alan Logan. "Triassic". University of New Brunswick. from the original on 26 April 2015.
  23. ^ a b c Ogg, James G.; Ogg, Gabi M.; Gradstein, Felix M. (2016). "Triassic". A concise geologic time scale 2016. Amsterdam, Netherlands: Elsevier. pp. 133–149. ISBN 978-0-444-63771-0.
  24. ^ Sahney, Sarda; Benton, Michael J (7 April 2008). "Recovery from the most profound mass extinction of all time". Proceedings of the Royal Society B: Biological Sciences. 275 (1636): 759–765. doi:10.1098/rspb.2007.1370. PMC 2596898. PMID 18198148.
  25. ^ Prothero, Donald R. (2013). Bringing fossils to life : an introduction to paleobiology (Third ed.). New York: Columbia University Press. pp. 504–506. ISBN 9780231158930.
  26. ^ Alan Kazlev. . unknown. Archived from the original on 27 April 2015.
  27. ^ Torsvik, Trond H.; Cocks, L. Robin M. (2017). Earth history and palaeogeography. Cambridge, United Kingdom: Cambridge University Press. ISBN 9781107105324.
  28. ^ Chen, Zhong-Qiang; Benton, Michael J. (June 2012). "The timing and pattern of biotic recovery following the end-Permian mass extinction". Nature Geoscience. 5 (6): 375–383. Bibcode:2012NatGe...5..375C. doi:10.1038/ngeo1475.
  29. ^ Looy, C. V.; Brugman, W. A.; Dilcher, D. L.; Visscher, H. (23 November 1999). "The delayed resurgence of equatorial forests after the Permian–Triassic ecologic crisis". Proceedings of the National Academy of Sciences. 96 (24): 13857–13862. Bibcode:1999PNAS...9613857L. doi:10.1073/pnas.96.24.13857. PMC 24155. PMID 10570163.
  30. ^ Blagoderov, V. A.; Lukashevich, E. D.; Mostovski, M. B. (2002). "Order Diptera Linné, 1758. The true flies". In Rasnitsyn, A. P.; Quicke, D. L. J. (eds.). History of Insects. Kluwer Academic Publishers. ISBN 978-1-4020-0026-3.
  31. ^ Stubbs, Thomas L.; Pierce, Stephanie E.; Rayfield, Emily J.; Anderson, Philip S. L. (2013). "Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction" (PDF). Proceedings of the Royal Society B. 280 (20131940): 20131940. doi:10.1098/rspb.2013.1940. PMC 3779340. PMID 24026826.
  32. ^ Rubidge. "Middle Triassic". unknown. from the original on 29 April 2015.
  33. ^ Tanner, Lawrence H. (2018). "Climates of the Late Triassic: Perspectives, Proxies and Problems". The Late Triassic World. Topics in Geobiology. 46: 59–90. doi:10.1007/978-3-319-68009-5_3. ISBN 978-3-319-68008-8.
  34. ^ Alcober, Oscar; Martínez, Ricardo (19 October 2010). "A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina". ZooKeys (63): 55–81. doi:10.3897/zookeys.63.550. PMC 3088398. PMID 21594020.
  35. ^ "Pterosaur distribution in time and space: an atlas" (PDF). Zitteliana: 61–107. 2008.
  36. ^ "Giant bones get archaeologists rethinking Triassic dinosaurs". The National. Retrieved 14 August 2018.
  37. ^ Britt, Brooks B.; Dalla Vecchia, Fabio M.; Chure, Daniel J.; Engelmann, George F.; Whiting, Michael F.; Scheetz, Rodney D. (13 August 2018). "Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years". Nature Ecology & Evolution. 2 (9): 1386–1392. doi:10.1038/s41559-018-0627-y. ISSN 2397-334X. PMID 30104753. S2CID 51984440.
  38. ^ Graham Ryder; David Fastovsky & Stefan Gartner (1 January 1996). Late Triassic Extinction. Geological Society of America. ISBN 9780813723075.
  39. ^ a b c d Carol Marie Tang. "Jurassic Era". California Academy of Sciences. from the original on 6 May 2015.
  40. ^ Hallam, A. (1982). "The Jurassic climate". Studies in Geophysics: Climate in Earth History. Washington, DC: National Academy Press. pp. 159–163. ISBN 0-309-03329-2. Retrieved 26 April 2021.
  41. ^ Iqbal, Shahid; Wagreich, Michael; U, Jan Urfan; Kuerschner, Wolfram Michael; Gier, Suzanne; Bibi, Mehwish (1 January 2019). "Hot-house climate during the Triassic/Jurassic transition: The evidence of climate change from the southern hemisphere (Salt Range, Pakistan)". Global and Planetary Change. 172: 15–32. Bibcode:2019GPC...172...15I. doi:10.1016/j.gloplacha.2018.09.008. S2CID 134048967.
  42. ^ Korte, Christoph; Hesselbo, Stephen P.; Ullmann, Clemens V.; Dietl, Gerd; Ruhl, Micha; Schweigert, Günter; Thibault, Nicolas (11 December 2015). "Jurassic climate mode governed by ocean gateway". Nature Communications. 6 (1): 10015. Bibcode:2015NatCo...610015K. doi:10.1038/ncomms10015. PMC 4682040. PMID 26658694.
  43. ^ a b c Torsvik & Cocks 2017, p. 217.
  44. ^ Marsh, Adam D.; Rowe, Timothy B. (2020). "A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona". Journal of Paleontology. 94 (S78): 1–103. doi:10.1017/jpa.2020.14.
  45. ^ Foth, Christian; Ezcurra, Martín D.; Sookias, Roland B.; Brusatte, Stephen L.; Butler, Richard J. (15 September 2016). "Unappreciated diversification of stem archosaurs during the Middle Triassic predated the dominance of dinosaurs". BMC Evolutionary Biology. 16 (1): 188. doi:10.1186/s12862-016-0761-6. PMC 5024528. PMID 27628503.
  46. ^ Meng, Jin; Wang, Yuanqing; Li, Chuankui (April 2011). "Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont". Nature. 472 (7342): 181–185. Bibcode:2011Natur.472..181M. doi:10.1038/nature09921. PMID 21490668. S2CID 4428972.
  47. ^ Smith, Felisa A.; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Dayan, Tamar; Ernest, S. K. Morgan; Evans, Alistair R.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; McCain, Christy; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Stephens, Patrick R.; Theodor, Jessica; Uhen, Mark D. (26 November 2010). "The Evolution of Maximum Body Size of Terrestrial Mammals". Science. 330 (6008): 1216–1219. Bibcode:2010Sci...330.1216S. doi:10.1126/science.1194830. PMID 21109666. S2CID 17272200.
  48. ^ Alan Kazlev. . unknown. Archived from the original on 1 June 2015. Retrieved 27 April 2015.
  49. ^ Skog, Judith E.; Dilcher, David L. (1 January 1994). "Lower vascular plants of the Dakota Formation in Kansas and Nebraska, USA". Review of Palaeobotany and Palynology. 80 (1–2): 1–18. doi:10.1016/0034-6667(94)90089-2.
  50. ^ Rogers, Kristina (2005). The Sauropods: Evolution and Paleobiology. Berkeley: U of California. doi:10.1525/9780520932333-017. S2CID 242669231.
  51. ^ Torsvik & Cocks 2017, pp. 217–218.
  52. ^ Tennant, Jonathan P.; Mannion, Philip D.; Upchurch, Paul (November 2016). "Sea level regulated tetrapod diversity dynamics through the Jurassic/Cretaceous interval". Nature Communications. 7 (1): 12737. Bibcode:2016NatCo...712737T. doi:10.1038/ncomms12737. PMC 5025807. PMID 27587285.
  53. ^ a b c Carl Fred Koch. "Cretaceous". Old Dominion University. from the original on 14 May 2015.
  54. ^ "Pterosaurs More Diverse at the End of the Cretaceous than Previously Thought". Everything Dinosaur Blog. Retrieved 14 August 2018.
  55. ^ University of California. "Cretaceous". University of California. from the original on 11 June 2017.
  56. ^ Elizabeth Howell (3 February 2015). "K-T Extinction event". Universe Today. from the original on 5 May 2015.
  57. ^ University of California. "Eocene Climate". University of California. from the original on 20 April 2015.
  58. ^ National Geographic Society. "Eocene". National Geographic. from the original on 8 May 2015.
  59. ^ "Neogene". Encyclopædia Britannica. from the original on 2 May 2015.
  60. ^ University of California. "Miocene". University of California. from the original on 4 May 2015.
  61. ^ University of California. "Pliocene". University of California. from the original on 29 April 2015.
  62. ^ Jonathan Adams. . Oak Ridge National Library. Archived from the original on 25 February 2015.
  63. ^ University of California. . University of California. Archived from the original on 24 August 2014. Retrieved 27 April 2015.
  64. ^ University of California. "Holocene". University of California. from the original on 2 May 2015.
  65. ^ "Sixth Extinction extinctions". Scientific American. from the original on 27 July 2014.
  66. ^ IUCN (3 November 2009). "Sixth Extinction". IUCN. from the original on 29 July 2012.
  67. ^ a b See, e. g., Markov, A.; Korotayev, A. (2008). "Hyperbolic growth of marine and continental biodiversity through the Phanerozoic and community evolution". Zhurnal Obshchei Biologii (Journal of General Biology). 69 (3): 175–194. PMID 18677962. from the original on 25 December 2009.

General references

  • Markov, Alexander V.; Korotayev, Andrey V. (2007). "Phanerozoic marine biodiversity follows a hyperbolic trend". Palaeoworld. 16 (4): 311–318. doi:10.1016/j.palwor.2007.01.002.
  • Miller, K. G.; Kominz, M. A.; Browning, J. V.; Wright, J. D.; Mountain, G. S.; Katz, M. E.; Sugarman, P. J.; Cramer, B. S.; Christie-Blick, N; Pekar, S. F.; et al. (2005). "The Phanerozoic record of global sea-level change" (PDF). Science. 310 (5752): 1293–1298. Bibcode:2005Sci...310.1293M. doi:10.1126/science.1116412. PMID 16311326. S2CID 7439713.

External links

  • Phanerozoic (chronostratigraphy scale)

phanerozoic, current, geologic, geologic, time, scale, during, which, abundant, animal, plant, life, existed, covers, million, years, present, began, with, cambrian, period, when, animals, first, developed, hard, shells, preserved, fossil, record, time, before. The Phanerozoic Eon 4 is the current geologic eon in the geologic time scale and the one during which abundant animal and plant life has existed It covers 538 8 million years ago to the present 5 and it began with the Cambrian Period when animals first developed hard shells preserved in the fossil record The time before the Phanerozoic called the Precambrian is now divided into the Hadean Archaean and Proterozoic eons Phanerozoic538 8 0 2 0 Ma Pha Proterozoic Archean Had Fauna and flora from each of the twelve periods of the Phanerozoic From top left Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene and Quaternary species Chronology 550 500 450 400 350 300 250 200 150 100 50 0 PhanerozoicNeoproterozoicPaleozoicMesozoicCenoCambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogene QuaternaryNeogene 538 8 485 4 443 8 419 2 358 9 298 9 251 902 201 4 145 66 2 58 23 03 million years ago Eras amp periods of the PhanerozoicEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal ICS Time scale s usedICS Time ScaleDefinitionChronological unitEonStratigraphic unitEonothemFirst proposed byGeorge Halcott Chadwick 1930Time span formalityFormalLower boundary definitionAppearance of the Ichnofossil Treptichnus pedumLower boundary GSSPFortune Head section Newfoundland Canada47 04 34 N 55 49 52 W 47 0762 N 55 8310 W 47 0762 55 8310Lower GSSP ratified1992Upper boundary definitionN AUpper boundary GSSPN AUpper GSSP ratifiedN AThe time span of the Phanerozoic starts with the sudden appearance of fossilised evidence of a number of animal phyla the evolution of those phyla into diverse forms the emergence and development of complex plants the evolution of fish the emergence of insects and tetrapods and the development of modern fauna Plant life on land appeared in the early Phanerozoic eon During this time span tectonic forces which move the continents had collected them into a single landmass known as Pangaea the most recent supercontinent which then separated into the current continental landmasses Contents 1 Etymology 2 Proterozoic Phanerozoic boundary 3 Eras of the Phanerozoic 3 1 Paleozoic Era 3 1 1 Cambrian Period 3 1 2 Ordovician Period 3 1 3 Silurian Period 3 1 4 Devonian Period 3 1 5 Carboniferous Period 3 1 6 Permian Period 3 2 Mesozoic Era 3 2 1 Triassic Period 3 2 2 Jurassic Period 3 2 3 Cretaceous Period 3 3 Cenozoic Era 3 3 1 Paleogene Period 3 3 2 Neogene Period 3 3 3 Quaternary Period 4 Biodiversity 5 See also 6 Citations 7 General references 8 External linksEtymology EditThe term Phanerozoic derives from the Ancient Greek words faneros phaneros meaning visible and zwh zōḗ meaning life since it was once believed that life began in the Cambrian the first period of this eon The term Phanerozoic was coined in 1930 by the American geologist George Halcott Chadwick 1876 1953 6 7 Proterozoic Phanerozoic boundary EditThe Proterozoic Phanerozoic boundary is at 538 8 million years ago 5 In the 19th century the boundary was set at time of appearance of the first abundant animal metazoan fossils but several hundred groups taxa of metazoa of the preceding Proterozoic eon have been identified since the systematic study of those forms started in the 1950s 8 9 Eras of the Phanerozoic EditThe Phanerozoic is divided into three eras the Paleozoic Mesozoic and Cenozoic which are further subdivided into 12 periods The Paleozoic features the evolution of fish amphibians and reptiles The Mesozoic features the evolution of lizards crocodiles snakes turtles mammals and dinosaurs including birds The Cenozoic begins with the extinction of the non avian dinosaurs and features evolution of great diversity in birds and mammals Humans appeared and evolved during the most recent part of the Cenozoic Paleozoic Era Edit Main article Paleozoic The Paleozoic is a time in Earth s history when complex life forms evolved took their first breath of oxygen on dry land and when the forerunners of all multicelular life on Earth began to diversify There are six periods in the Paleozoic era Cambrian Ordovician Silurian Devonian Carboniferous and Permian 10 Cambrian Period Edit Main article CambrianThe Cambrian is the first period of the Paleozoic Era and ran from 539 million to 485 million years ago The Cambrian sparked a rapid expansion in the diversity of animals in an event known as the Cambrian explosion during which the greatest number of animal body plans evolved in a single period in the history of Earth Complex algae evolved and the fauna was dominated by armoured arthropods such as trilobites Almost all phyla of marine animals evolved in this period During this time the super continent Pannotia began to break up most of which later recombined into the super continent Gondwana 11 Ordovician Period Edit Main article Ordovician The Ordovician spans from 485 million to 444 million years ago The Ordovician was a time in Earth s history in which many groups still prevalent today evolved or diversified such as primitive cephalopods fish and corals This process is known as the Great Ordovician Biodiversification Event or GOBE Trilobites began to be replaced by articulate brachiopods and crinoids also became an increasingly important part of the fauna 12 The first arthropods crept ashore to colonise Gondwana a continent empty of animal life By the end of the Ordovician Gondwana had moved from the equator to the South Pole and Laurentia had collided with Baltica closing the Iapetus Ocean The glaciation of Gondwana resulted in a major drop in sea level killing off all life that had established along its coast Glaciation caused an icehouse Earth leading to the Ordovician Silurian extinction during which 60 of marine invertebrates and 25 of families became extinct Though one of the deadliest mass extinctions in earth s history the O S extinction did not cause profound ecological changes between the periods 13 Silurian Period Edit Main article Silurian Dalmanites limulurus a species of Silurian trilobites The Silurian spans from 444 million to 419 million years ago which saw a warming from an icehouse Earth This period saw the mass evolution of fish as jawless fish became more numerous and early jawed and freshwater fish appeared in the fossil record Arthropods remained abundant and some groups such as eurypterids became apex predators Fully terrestrial life established itself on land including early arachnids fungi and myriapods many legged arthropods The evolution of vascular plants such as Cooksonia allowed plants to gain a foothold on land as well These early terrestrial plants are the forerunners of all plant life on land During this time there were four continents Gondwana Africa South America Australia Antarctica India Laurentia North America with parts of Europe Baltica the rest of Europe and Siberia Northern Asia 14 Devonian Period Edit Main article Devonian Cephalaspis a jawless fish The Devonian spans from 419 million to 359 million years ago Also informally known as the Age of the Fish the Devonian features a huge diversification in fish Armored fish included jawless agnathans as well as jawed placoderms such as Dunkleosteus The Devonian also saw a diversification of modern fish groups such as chondricthyans sharks and kin osteichthyans ray finned fish and sarcopterygians lobe finned fish One lineage of sarcopterygians evolved into the first four limbed vertebrates which would eventually become tetrapods On land plant groups diversified the first trees and seeds evolved during this period By the Middle Devonian shrub like forests of early plants existed lycophytes horsetails ferns and progymnosperm This event also allowed the diversification of arthropod life as they took advantage of the new habitat Near the end of the Devonian 70 of all species became extinct in a sequence of mass extinction events collectively known as the Late Devonian extinction 15 Carboniferous Period Edit Main article Carboniferous Proterogyrinus a Carboniferous amphibian non amniote tetrapod The Carboniferous spans from 359 million to 299 million years ago 16 Tropical swamps dominated the Earth and the large amounts of trees created much of the carbon that became coal deposits hence the name Carboniferous About 90 of all coal beds were deposited in the Carboniferous and Permian periods which represent just 2 of the Earth s geologic history 17 The high oxygen levels caused by these swamps allowed massive arthropods normally limited in size by their respiratory systems to proliferate Tetrapods diversified during the Carboniferous and one lineage acquired an amniotic egg which could survive outside of the water These tetrapods the amniotes included the first reptiles and synapsids mammal relatives Throughout the Carboniferous there was a cooling pattern which eventually led to the glaciation of Gondwana as much of it was situated around the south pole This event was known as the Permo Carboniferous Glaciation and resulted in a major loss of area for coal forests the Carboniferous rainforest collapse 18 Permian Period Edit Main article Permian Dimetrodon grandis a synapsid from the early Permian The Permian spans from 298 million to 251 million years ago and was the last period of the Paleozoic era At its beginning all continents came together to form the super continent Pangaea surrounded by one ocean called Panthalassa The Earth was relatively dry compared to the Carboniferous with harsh seasons as the climate of the interior of Pangaea was not moderated by large bodies of water Amniotes flourished and diversified in the new dry climate particularly synapsids such as Dimetrodon Edaphosaurus and the ancestors of modern mammals The first conifers evolved during this period then dominated the terrestrial landscape The Permian ended with at least one mass extinction the Permian Triassic mass extinction an event sometimes known as the Great Dying This extinction was the largest in earth s history and led to the loss of 95 of all species of life 19 20 Mesozoic Era Edit Main article Mesozoic The Mesozoic ranges from 252 million to 66 million years ago Also referred to as the Age of Reptiles or Age of Conifers 21 the Mesozoic featured the appearance of many modern tetrapods as reptiles ascended to ecological dominance over synapsids The Mesozoic is subdivided into three periods the Triassic Jurassic and Cretaceous Triassic Period Edit Main article Triassic The Triassic ranges from 252 million to 201 million years ago The Triassic is a transitional time in Earth s history between the Permian Extinction and the lush Jurassic Period It has three major epochs Early Triassic Middle Triassic and Late Triassic 22 The Early Triassic lasted between 252 million to 247 million years ago 23 and was a hot and arid epoch in the aftermath of the Permian Extinction Many tetrapods during this epoch represented a disaster fauna a group of animals with low diversity and cosmopolitanism wide geographic ranges 24 Temnospondyli recovered and rediversified into large aquatic predators during the Triassic 25 26 Reptiles also diversified rapidly with aquatic reptiles such as ichthyosaurs and sauropterygians proliferating in the seas On land the first true archosaurs appeared including pseudosuchians crocodile relatives and avemetatarsalians bird dinosaur relatives Plateosaurus an early sauropodomorph dinosaur The Middle Triassic spans from 247 million to 237 million years ago 23 The Middle Triassic featured the beginnings of the break up of Pangaea as rifting commenced in north Pangaea The northern part of the Tethys Ocean the Paleotethys Ocean had become a passive basin but a spreading center was active in the southern part of the Tethys Ocean the Neotethys Ocean 27 Phytoplankton coral crustaceans and many other invertebrates recovered from the Permian extinction by the end of the Middle Triassic 28 Meanwhile on land reptiles continued to diversify conifer forests flourished 29 as well as the first flies 30 31 32 The Late Triassic spans from 237 million to 201 million years ago 23 Following the bloom of the Middle Triassic the Late Triassic was warm and arid with a strong monsoon climate and with most precipitation limited to coastal regions and high latitudes 33 The first true dinosaurs appeared early in the Late Triassic 34 and pterosaurs evolved a bit later 35 36 37 Other large reptilian competitors to the dinosaurs were wiped out by the Triassic Jurassic extinction event in which most archosaurs excluding crocodylomorphs pterosaurs and dinosaurs many synapsids and almost all large amphibians became extinct as well as 34 of marine life in the fourth mass extinction event The cause of the extinction is debated but likely resulted from eruptions of the CAMP large igneous province 38 Jurassic Period Edit Main article Jurassic Sericipterus a pterosaur The Jurassic ranges from 201 million to 145 million years ago and features three major epochs Early Jurassic Middle Jurassic and Late Jurassic 39 The Early Jurassic Epoch spans from 201 million to 174 million years ago 39 The climate was much more humid than during the Triassic and as a result the world was warm and partially tropical 40 41 though possibly with short colder intervals 42 Plesiosaurs ichthyosaurs and ammonites dominated the seas 43 while dinosaurs and other reptiles dominated the land 43 with species such as Dilophosaurus at the apex 44 Crocodylomorphs evolved into aquatic forms pushing the large amphibians to near extinction 45 43 True mammals were present during the Jurassic 46 but remained small with average body masses of less than 10 kilograms 22 lb until the end of the Cretaceous 47 48 Stegosaurus a large ornithischian dinosaur from the Late Jurassic The Middle and Late Jurassic Epochs span from 174 million to 145 million years ago 39 Conifer savannahs made up a large portion of the world s forests 49 50 In the oceans plesiosaurs were quite common and ichthyosaurs were flourishing 51 The Late Jurassic Epoch spans from 163 million to 145 million years ago 39 The Late Jurassic featured a severe extinction of sauropods in northern continents alongside many ichthyosaurs However the Jurassic Cretaceous boundary did not strongly impact most forms of life 52 Cretaceous Period Edit Main article Cretaceous The Cretaceous is the Phanerozoic s longest period and the last period of the Mesozoic It spans from 145 million to 66 million years ago and is divided into two epochs Early Cretaceous and Late Cretaceous 53 Tylosaurus a type of large marine lizards known as mosasaurs The Early Cretaceous Epoch spans from 145 million to 100 million years ago 53 Dinosaurs continued to be abundant with groups such as tyrannosauroids avialans birds marginocephalians and ornithopods seeing early glimpses of later success Other tetrapods such as stegosaurs and ichthyosaurs declined significantly and sauropods were restricted to southern continents The Late Cretaceous Epoch spans from 100 million to 66 million years ago 53 The Late Cretaceous featured a cooling trend that would continue into the Cenozoic Era Eventually the tropical climate was restricted to the equator and areas beyond the tropic lines featured more seasonal climates Dinosaurs still thrived as new species such as Tyrannosaurus Ankylosaurus Triceratops and hadrosaurs dominated the food web Whether or not pterosaurs went into a decline as birds radiated is debated however many families survived until the end of the Cretaceous alongside new forms such as the gigantic Quetzalcoatlus 54 Mammals diversified despite their small sizes with metatherians marsupials and kin and eutherians placentals and kin coming into their own In the oceans mosasaurs diversified to fill the role of the now extinct ichthyosaurs alongside huge plesiosaurs such as Elasmosaurus Also the first flowering plants evolved At the end of the Cretaceous the Deccan Traps and other volcanic eruptions were poisoning the atmosphere As this was continued it is thought that a large meteor smashed into Earth creating the Chicxulub Crater and the event known as the K Pg extinction the fifth and most recent mass extinction event during which 75 of life on Earth became extinct including all non avian dinosaurs Every living thing with a body mass over 10 kilograms became extinct and the age of the dinosaurs came to an end 55 56 Cenozoic Era Edit Main article Cenozoic The Cenozoic featured the rise of mammals as the dominant class of animals as the end of the age of the dinosaurs left significant open niches There are three divisions of the Cenozoic Paleogene Neogene and Quaternary Paleogene Period Edit Main article Paleogene The Paleogene spans from the extinction of the non avian dinosaurs some 66 million years ago to the dawn of the Neogene 23 million years ago It features three epochs Paleocene Eocene and Oligocene Basilosaurus was an early cetacean related to modern whales The Paleocene Epoch began with the K Pg extinction event and the early part of the Paleocene saw the recovery of the Earth from that event The continents began to take their modern shapes but most continents and India remained separated from each other Africa and Eurasia were separated by the Tethys Sea and the Americas were separated by the strait of Panama as the Isthmus of Panama had not yet formed This epoch featured a general warming trend and the earliest modern jungles expanded eventually reaching the poles The oceans were dominated by sharks as the large reptiles that had once ruled had become extinct Mammals diversified rapidly but most remained small The largest tetrapod carnivores during the Paleocene were reptiles including crocodyliforms choristoderans and snakes Titanoboa the largest known snake lived in South America during the Paleocene The Eocene Epoch ranged from 56 million to 34 million years ago In the early Eocene most land mammals were small and living in cramped jungles much like the Paleocene Among them were early primates whales and horses along with many other early forms of mammals The climate was warm and humid with little temperature gradient from pole to pole In the Middle Eocene Epoch the circum Antarctic current between Australia and Antarctica formed disrupting ocean currents worldwide resulting in global cooling and causing the jungles to shrink More modern forms of mammals continued to diversify with the cooling climate even as more archaic forms died out By the end of the Eocene whales such as Basilosaurus had become fully aquatic The late Eocene Epoch saw the rebirth of seasons which caused the expansion of savanna like areas with the earliest substantial grasslands 57 58 At the transition between the Eocene and Oligocene epochs there was a significant extinction event the cause of which is debated The Oligocene Epoch spans from 34 million to 23 million years ago The Oligocene was an important transitional period between the tropical world of the Eocene and more modern ecosystems This period featured a global expansion of grass which led to many new species taking advantage including the first elephants cats dogs marsupials and many other species still prevalent today Many other species of plants evolved during this epoch also such as the evergreen trees The long term cooling continued and seasonal rain patterns established Mammals continued to grow larger Paraceratherium one of the largest land mammals to ever live evolved during this epoch along with many other perissodactyls Neogene Period Edit Main article Neogene The Neogene spans from 23 03 million to 2 58 million years ago It features two epochs the Miocene and the Pliocene 59 The Miocene spans from 23 03 million to 5 333 million years ago and is a period in which grass spread further across effectively dominating a large portion of the world diminishing forests in the process Kelp forests evolved leading to the evolution of new species such as sea otters During this time perissodactyls thrived and evolved into many different varieties Alongside them were the apes which evolved into 30 species Overall arid and mountainous land dominated most of the world as did grazers The Tethys Sea finally closed with the creation of the Arabian Peninsula and in its wake left the Black Red Mediterranean and Caspian Seas This only increased aridity Many new plants evolved and 95 of modern seed plants evolved in the mid Miocene 60 The Pliocene lasted from 5 333 million to 2 58 million years ago The Pliocene featured dramatic climatic changes which ultimately led to modern species and plants The Mediterranean Sea dried up for hundreds of thousand years in the Messinian salinity crisis Along with these major geological events Africa saw the appearance of Australopithecus the ancestor of Homo The isthmus of Panama formed and animals migrated between North and South America wreaking havoc on the local ecology Climatic changes brought savannas that are still continuing to spread across the world Indian monsoons deserts in East Asia and the beginnings of the Sahara desert The Earth s continents and seas moved into their present shapes The world map has not changed much since save for changes brought about by the glaciations of the Quaternary such as the Great Lakes 61 62 Quaternary Period Edit Main article Quaternary Megafauna of the Pleistocene mammoths cave lions woolly rhinos reindeer horses The Quaternary spans from 2 58 million years ago to present day and is the shortest geological period in the Phanerozoic Eon It features modern animals and dramatic changes in the climate It is divided into two epochs the Pleistocene and the Holocene The Pleistocene lasted from 2 58 million to 11 700 years ago This epoch was marked by a series of glacial periods ice ages as a result of the cooling trend that started in the Mid Eocene There were numerous separate glaciation periods marked by the advance of ice caps as far south as 40 degrees N latitude in mountainous areas Meanwhile Africa experienced a trend of desiccation which resulted in the creation of the Sahara Namib and Kalahari deserts Mammoths giant ground sloths dire wolves sabre toothed cats and humans were common and widespread during the Pleistocene As the Pleistocene drew to a close a major extinction wiped out much of the world s megafauna including non Homo sapiens human species such as Homo neanderthalensis All the continents were affected but Africa was impacted to a lesser extent That continent retained many large animals such as elephants rhinos and hippos The extent to which Homo Sapiens were involved in this extinction is debated 63 The Holocene began 11 700 years ago and lasts until the present day All recorded history and Human history lies within the boundaries of the Holocene epoch 64 Human activity is blamed for an ongoing mass extinction that began roughly 10 000 years ago though the species becoming extinct have only been recorded since the Industrial Revolution This is sometimes referred to as the Sixth Extinction Hundreds of species have become extinct due to human activity since the Industrial Revolution 65 66 Biodiversity Edit During the Phanerozoic biodiversity shows an overall but not monotonic increase from near zero to several thousands of genera It has been demonstrated that changes in biodiversity through the Phanerozoic correlate much better with the hyperbolic model widely used in demography and macrosociology than with exponential and logistic models traditionally used in population biology and extensively applied to fossil biodiversity as well The latter models imply that changes in diversity are guided by a first order positive feedback more ancestors more descendants or a negative feedback that arises from resource limitation or both The hyperbolic model implies a second order positive feedback The hyperbolic pattern of the human population growth arises from quadratic positive feedback caused by the interaction of the population size and the rate of technological growth 67 The character of biodiversity growth in the Phanerozoic Eon can be similarly accounted for by a feedback between the diversity and community structure complexity It has been suggested that the similarity between the curves of biodiversity and human population probably comes from the fact that both are derived from the superposition on the hyperbolic trend of cyclical and random dynamics 67 See also Edit Global map reconstruction showing continents at 500 million years ago Global maps showing continental movement from 250 million years ago to present day Paleoclimatology Study of changes in ancient climateCitations Edit Phanerozoic Lexico UK English Dictionary Oxford University Press Archived from the original on 6 August 2020 Phanerozoic Merriam Webster Dictionary Phanerozoic Dictionary com Unabridged Online n d There are several ways of pronouncing Phanerozoic including ˌ f ae n er e ˈ z oʊ ɪ k ˌ f ae n r e r oʊ FAN er e ZOH ik FAN re roh 1 2 3 a b Stratigraphic Chart 2022 PDF International Stratigraphic Commission February 2022 Retrieved 20 April 2022 Chadwick G H 1930 Subdivision of geologic time Bulletin of the Geological Society of America 41 47 48 Harland B et al eds 1990 A geologic timescale 1989 Cambridge Cambridge University Press p 30 ISBN 0 521 38361 7 Glaessner Martin F 1961 Precambrian Animals Scientific American 204 3 72 78 Bibcode 1961SciAm 204c 72G doi 10 1038 scientificamerican0361 72 Geyer Gerd Landing Ed 2017 The Precambrian Phanerozoic and Ediacaran Cambrian boundaries a historical approach to a dilemma Geological Society London Special Publications 448 1 311 349 Bibcode 2017GSLSP 448 311G doi 10 1144 SP448 10 S2CID 133538050 University of California Paleozoic University of California Archived from the original on 2 May 2015 University of California Cambrian University of California Archived from the original on 15 May 2012 Cooper John D Miller Richard H Patterson Jacqueline 1986 A Trip Through Time Principles of Historical Geology Columbus Merrill Publishing Company pp 247 255 259 ISBN 978 0 675 20140 7 University of California Ordovician University of California Archived from the original on 2 May 2015 University of California Silurian University of California Archived from the original on 16 June 2017 University of California Devonian University of California Archived from the original on 11 May 2012 Monte Hieb Carboniferous Era unknown Archived from the original on 20 December 2014 McGhee George R 2018 Carboniferous giants and mass extinction the late Paleozoic Ice Age world New York Columbia University Press p 98 ISBN 9780231180979 University of California Carboniferous University of California Archived from the original on 10 February 2012 Natural History Museum The Great Dying Natural History Museum Archived from the original on 20 April 2015 University of California Permian Era University of California Archived from the original on 4 July 2017 Dean Dennis R 1999 Gideon Mantell and the Discovery of Dinosaurs Cambridge University Press pp 97 98 ISBN 978 0521420488 Alan Logan Triassic University of New Brunswick Archived from the original on 26 April 2015 a b c Ogg James G Ogg Gabi M Gradstein Felix M 2016 Triassic A concise geologic time scale 2016 Amsterdam Netherlands Elsevier pp 133 149 ISBN 978 0 444 63771 0 Sahney Sarda Benton Michael J 7 April 2008 Recovery from the most profound mass extinction of all time Proceedings of the Royal Society B Biological Sciences 275 1636 759 765 doi 10 1098 rspb 2007 1370 PMC 2596898 PMID 18198148 Prothero Donald R 2013 Bringing fossils to life an introduction to paleobiology Third ed New York Columbia University Press pp 504 506 ISBN 9780231158930 Alan Kazlev Early Triassic unknown Archived from the original on 27 April 2015 Torsvik Trond H Cocks L Robin M 2017 Earth history and palaeogeography Cambridge United Kingdom Cambridge University Press ISBN 9781107105324 Chen Zhong Qiang Benton Michael J June 2012 The timing and pattern of biotic recovery following the end Permian mass extinction Nature Geoscience 5 6 375 383 Bibcode 2012NatGe 5 375C doi 10 1038 ngeo1475 Looy C V Brugman W A Dilcher D L Visscher H 23 November 1999 The delayed resurgence of equatorial forests after the Permian Triassic ecologic crisis Proceedings of the National Academy of Sciences 96 24 13857 13862 Bibcode 1999PNAS 9613857L doi 10 1073 pnas 96 24 13857 PMC 24155 PMID 10570163 Blagoderov V A Lukashevich E D Mostovski M B 2002 Order Diptera Linne 1758 The true flies In Rasnitsyn A P Quicke D L J eds History of Insects Kluwer Academic Publishers ISBN 978 1 4020 0026 3 Stubbs Thomas L Pierce Stephanie E Rayfield Emily J Anderson Philip S L 2013 Morphological and biomechanical disparity of crocodile line archosaurs following the end Triassic extinction PDF Proceedings of the Royal Society B 280 20131940 20131940 doi 10 1098 rspb 2013 1940 PMC 3779340 PMID 24026826 Rubidge Middle Triassic unknown Archived from the original on 29 April 2015 Tanner Lawrence H 2018 Climates of the Late Triassic Perspectives Proxies and Problems The Late Triassic World Topics in Geobiology 46 59 90 doi 10 1007 978 3 319 68009 5 3 ISBN 978 3 319 68008 8 Alcober Oscar Martinez Ricardo 19 October 2010 A new herrerasaurid Dinosauria Saurischia from the Upper Triassic Ischigualasto Formation of northwestern Argentina ZooKeys 63 55 81 doi 10 3897 zookeys 63 550 PMC 3088398 PMID 21594020 Pterosaur distribution in time and space an atlas PDF Zitteliana 61 107 2008 Giant bones get archaeologists rethinking Triassic dinosaurs The National Retrieved 14 August 2018 Britt Brooks B Dalla Vecchia Fabio M Chure Daniel J Engelmann George F Whiting Michael F Scheetz Rodney D 13 August 2018 Caelestiventus hanseni gen et sp nov extends the desert dwelling pterosaur record back 65 million years Nature Ecology amp Evolution 2 9 1386 1392 doi 10 1038 s41559 018 0627 y ISSN 2397 334X PMID 30104753 S2CID 51984440 Graham Ryder David Fastovsky amp Stefan Gartner 1 January 1996 Late Triassic Extinction Geological Society of America ISBN 9780813723075 a b c d Carol Marie Tang Jurassic Era California Academy of Sciences Archived from the original on 6 May 2015 Hallam A 1982 The Jurassic climate Studies in Geophysics Climate in Earth History Washington DC National Academy Press pp 159 163 ISBN 0 309 03329 2 Retrieved 26 April 2021 Iqbal Shahid Wagreich Michael U Jan Urfan Kuerschner Wolfram Michael Gier Suzanne Bibi Mehwish 1 January 2019 Hot house climate during the Triassic Jurassic transition The evidence of climate change from the southern hemisphere Salt Range Pakistan Global and Planetary Change 172 15 32 Bibcode 2019GPC 172 15I doi 10 1016 j gloplacha 2018 09 008 S2CID 134048967 Korte Christoph Hesselbo Stephen P Ullmann Clemens V Dietl Gerd Ruhl Micha Schweigert Gunter Thibault Nicolas 11 December 2015 Jurassic climate mode governed by ocean gateway Nature Communications 6 1 10015 Bibcode 2015NatCo 610015K doi 10 1038 ncomms10015 PMC 4682040 PMID 26658694 a b c Torsvik amp Cocks 2017 p 217 Marsh Adam D Rowe Timothy B 2020 A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli Dinosauria Theropoda with descriptions of new specimens from the Kayenta Formation of northern Arizona Journal of Paleontology 94 S78 1 103 doi 10 1017 jpa 2020 14 Foth Christian Ezcurra Martin D Sookias Roland B Brusatte Stephen L Butler Richard J 15 September 2016 Unappreciated diversification of stem archosaurs during the Middle Triassic predated the dominance of dinosaurs BMC Evolutionary Biology 16 1 188 doi 10 1186 s12862 016 0761 6 PMC 5024528 PMID 27628503 Meng Jin Wang Yuanqing Li Chuankui April 2011 Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont Nature 472 7342 181 185 Bibcode 2011Natur 472 181M doi 10 1038 nature09921 PMID 21490668 S2CID 4428972 Smith Felisa A Boyer Alison G Brown James H Costa Daniel P Dayan Tamar Ernest S K Morgan Evans Alistair R Fortelius Mikael Gittleman John L Hamilton Marcus J Harding Larisa E Lintulaakso Kari Lyons S Kathleen McCain Christy Okie Jordan G Saarinen Juha J Sibly Richard M Stephens Patrick R Theodor Jessica Uhen Mark D 26 November 2010 The Evolution of Maximum Body Size of Terrestrial Mammals Science 330 6008 1216 1219 Bibcode 2010Sci 330 1216S doi 10 1126 science 1194830 PMID 21109666 S2CID 17272200 Alan Kazlev Early Jurassic unknown Archived from the original on 1 June 2015 Retrieved 27 April 2015 Skog Judith E Dilcher David L 1 January 1994 Lower vascular plants of the Dakota Formation in Kansas and Nebraska USA Review of Palaeobotany and Palynology 80 1 2 1 18 doi 10 1016 0034 6667 94 90089 2 Rogers Kristina 2005 The Sauropods Evolution and Paleobiology Berkeley U of California doi 10 1525 9780520932333 017 S2CID 242669231 Torsvik amp Cocks 2017 pp 217 218 Tennant Jonathan P Mannion Philip D Upchurch Paul November 2016 Sea level regulated tetrapod diversity dynamics through the Jurassic Cretaceous interval Nature Communications 7 1 12737 Bibcode 2016NatCo 712737T doi 10 1038 ncomms12737 PMC 5025807 PMID 27587285 a b c Carl Fred Koch Cretaceous Old Dominion University Archived from the original on 14 May 2015 Pterosaurs More Diverse at the End of the Cretaceous than Previously Thought Everything Dinosaur Blog Retrieved 14 August 2018 University of California Cretaceous University of California Archived from the original on 11 June 2017 Elizabeth Howell 3 February 2015 K T Extinction event Universe Today Archived from the original on 5 May 2015 University of California Eocene Climate University of California Archived from the original on 20 April 2015 National Geographic Society Eocene National Geographic Archived from the original on 8 May 2015 Neogene Encyclopaedia Britannica Archived from the original on 2 May 2015 University of California Miocene University of California Archived from the original on 4 May 2015 University of California Pliocene University of California Archived from the original on 29 April 2015 Jonathan Adams Pliocene climate Oak Ridge National Library Archived from the original on 25 February 2015 University of California Pleistocene University of California Archived from the original on 24 August 2014 Retrieved 27 April 2015 University of California Holocene University of California Archived from the original on 2 May 2015 Sixth Extinction extinctions Scientific American Archived from the original on 27 July 2014 IUCN 3 November 2009 Sixth Extinction IUCN Archived from the original on 29 July 2012 a b See e g Markov A Korotayev A 2008 Hyperbolic growth of marine and continental biodiversity through the Phanerozoic and community evolution Zhurnal Obshchei Biologii Journal of General Biology 69 3 175 194 PMID 18677962 Archived from the original on 25 December 2009 General references EditMarkov Alexander V Korotayev Andrey V 2007 Phanerozoic marine biodiversity follows a hyperbolic trend Palaeoworld 16 4 311 318 doi 10 1016 j palwor 2007 01 002 Miller K G Kominz M A Browning J V Wright J D Mountain G S Katz M E Sugarman P J Cramer B S Christie Blick N Pekar S F et al 2005 The Phanerozoic record of global sea level change PDF Science 310 5752 1293 1298 Bibcode 2005Sci 310 1293M doi 10 1126 science 1116412 PMID 16311326 S2CID 7439713 External links Edit Wikimedia Commons has media related to Phanerozoic Phanerozoic chronostratigraphy scale Retrieved from https en wikipedia org w index php title Phanerozoic amp oldid 1151943529, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.