Battle of Issus - wikipedia Battle of Issus Jump to : navigation , search For other uses , see Battle of Issus ( disambiguation ) . Coordinates : 36 ° 50 ′ 16 '' N 36 ° 12 ′ 40 '' E  /  36.837894 ° N 36.211109 ° E  / 36.837894 ; 36.211109 Battle of Issus Part of the Wars of Alexander the Great Alexander battling Darius at the Battle of Issus ( Naples National Archaeological Museum ) Date November 5 , 333 BC Location Issus , Achaemenid Empire ( modern - day Turkey ) Result Decisive Greek victory Territorial changes Alexander controls southern Asia Minor Belligerents Macedon League of Corinth Achaemenid Empire Commanders and leaders Alexander the Great Parmenion Craterus Hephaestion Ptolemy Pantordanus Sitalces II Menes Balacrus Darius III Arsames † Rheomithres † Atizyes † Bubaces † Sabaces † Strength 13,000 peltasts , 22,000 heavy infantry , 5,850 cavalry Total : 40,850 30,000 -- 80,000 light infantry ( Babylonian spears , Ionian peltasts ) 11,000 cavalry 10,000 Persian Immortals 10,000 Greek mercenaries Total : 61,000 -- 108,000 ( modern sources ) 250,000 -- 600,000 ( ancient sources ) Casualties and losses 452 and many wounded ~ 20,000 ( hide ) Alexander 's Persian campaigns Granicus ( 334 BC ) Miletus ( 334 BC ) Halicarnassus ( 334 BC ) Issus ( 333 BC ) Tyre ( 332 BC ) Gaza ( 332 BC ) Gaugamela ( 331 BC ) Uxian Defile ( 331 BC ) Persian Gate ( 330 BC ) Cyropolis ( 329 BC ) Jaxartes ( 329 BC ) Gabai ( 328 BC ) Sogdian Rock ( 327 BC ) The Battle of Issus occurred in southern Anatolia , on November 5 , 333 BC between the Hellenic League led by Alexander the Great and the Achaemenid Empire , led by Darius III , in the second great battle of Alexander 's conquest of Asia . The invading Macedonian troops defeated Persia . After the Hellenic League soundly defeated the Persian satraps of Asia Minor ( led by Greek mercenary Memnon of Rhodes ) at the Battle of the Granicus , Darius took personal command of his army . He gathered reinforcements and led his men in a surprise march behind the Hellenic advance to cut their line of supply . This forced Alexander to countermarch , setting the stage for the battle near the mouth of the Pinarus River and the town of Issus . Contents ( hide ) 1 Location 2 Background 3 Motives 4 Combatants 4.1 Persian army 4.2 Macedonian army 5 Battle 6 Aftermath 7 Depictions of the battle 8 References 9 Sources 9.1 Ancient 9.2 Modern 10 External links Location The battle of Issus by Jan Brueghel the Elder in the Louvre The battle took place south of the ancient town Issus , which is close to the present - day Turkish town of Iskenderun ( the Turkish equivalent of `` Alexandria '' , founded by Alexander to commemorate his victory ) , on either side of a small river called Pinarus . At that location , the distance from the Gulf of Issus to the surrounding mountains is only 2.6 km ( 2 mi ) , a place where Darius could not take advantage of his superiority in numbers . Speculation on the location of the Pinarus has taken place for over 80 years . Older historians believed it to be the Deli Tchai river , but historians N.G.L. Hammond and A.M. Devine claim that the Pinarus is actually the Payas River , the latter using his own examination of the course of the river , which he considered would not have drastically changed since antiquity . Their evidence is based on Callisthenes ' accounts of the measurements of the battlefield and distances marched by both sides ' armies in the prelude to the battle and distance given by Diodorus after the battle . Background Movements to the battlefield . Red indicates Persian forces , and blue indicates Macedonian forces . Alexander set out into Asia in 334 BC and defeated the local Persian satraps at the Battle of the Granicus . He then proceeded to occupy all of Asia Minor , with the idea of capturing all coastal settlements so as to negate the power of the vastly superior Persian fleet . He captured several important settlements such as Miletus in 334 BC and Halicarnassus , a siege lasting four months , starting in late December the same year . While Alexander was in Tarsus , he heard of Darius massing a great army in Babylon . If Darius were to reach the Gulf of Issus , he could use the support from the Persian fleet under Pharnabazus still operating in the Mediterranean Sea , thus easing his supply and possibly landing troops behind the enemy . Alexander kept his main army at Tarsus but sent Parmenion ahead to occupy the coast around Issus . In November , Alexander received reports that the great Persian army had advanced into Syria to a town named Sochoi . Alexander decided to mass his scattered army and advance south from Issus through the Pass of Jonah . Darius knew that Parmenion held the Pass of Jonah and thus chose a northern route of advance . The Persians captured Issus without opposition and cut off the hands of all the sick and wounded that Alexander had left behind . Now Darius found out he had placed his army behind the Hellenic League and had cut their supply lines . He then advanced to the south and got no further than the river Pinarus before his scouts spotted Alexander marching north . Darius had to set up camp on this narrow coastal plain . Motives Initial dispositions of Persian and Macedonian forces There is much debate as to the motives of Alexander and Darius preceding Issus . One modern perspective , based on Curtius , is that Darius was forced to move camp to terrain that favored Alexander because Alexander was fighting defensively due to a recommendation by his war council and Parmenion . Darius ' large army could not be supported in the field during winter and his cities in Phoenicia were already in unrest at the arrival of Alexander . Darius was forced to move his large army to a small battlefield , greatly to the advantage of Alexander 's smaller force . Alexander was waiting for Darius to come south around the Amanus Mountain range because the pass Darius would have used , the Belen Pass , was much closer to Sochi and offered the quickest access to the area Alexander defended . Alexander was waiting 15 km ( 9.3 mi ) to the west of the Belen Pass at Myriandrus to spring a trap on Darius as he crossed through the Belen Pass or through the Pillar of Jonah if he moved north , where Darius ' army would be disorganized and disjointed in the narrow crossing . Darius instead moved north from Sochi and around the mountains , emerging behind Alexander 's position and on his supply and communication lines . Thus Alexander was forced to march to Darius , who had caught him off guard in a large flanking maneuver . This gives the illusion that Darius was the one acting defensively , since Alexander was forced to march to him . Combatants Persian army Some ancient sources ( Arrian and Plutarch ) , who based their accounts on earlier Greek sources , estimated 600,000 Persian soldiers in total , while Diodorus and Justin estimated 400,000 , and Curtius Rufus estimated 250,000 . Modern historians find Arrian 's count of 600,000 men highly unlikely . They argue that the logistics of fielding more than 100,000 soldiers in battle was extremely difficult at the time . Hans Delbrück gives an estimate as small as 25,000 , although most ( including Engels and Green ) estimate the total size of Darius ' army to be no larger than 100,000 at Issus , including 11,000 cavalry , 10,000 Persian Immortals , and 10,000 Greek mercenaries . Warry estimates 108,000 in total . Macedonian army The size of the Hellenic army may not have exceeded 40,000 men , including their other allies , led by Alexander . Alexander 's army may have consisted of about 22,000 phalangites and hoplites , 13,000 peltasts , and 5,850 cavalry . Battle The Greeks advanced through the Pillar of Jonah . Alexander led his Companion cavalry on the right flank and he set his Thessalian allied cavalry on the left of the phalanx with Parmenion in command . Darius formed his line with his heavy cavalry concentrated next to the coast on his right , followed by the Greek mercenary phalanx ( historian A.M. Devine places them at a strength of 12,000 , comparable to Alexander 's Greek phalanx ) . Next to the Greek phalanx Darius spread his Persian infantry , the Cardaces , along the river and into the foothills , where they wrapped around to the other bank and threatened Alexander 's right flank ( the formation resembled gamma , Γ ) . Arrian gives an inflated figure of 20,000 to these troops . Darius positioned himself in the centre with his best infantry , the Greek mercenaries , and his royal cavalry guard . According to some historians , like P. Stratikis , he was trying to replicate the Hellenic battle formation of the Battle of the Granicus . Alexander 's decisive attack The Persian cavalry first charged Parmenion and the allied cavalry , crossing the river to open battle . Alexander 's right wing became the crux of the battle , as at Gaugamela two years later , where Parmenion held the left wing long enough against superior Persian numbers for Alexander to make his calculated cavalry strike against Darius and break the Persian army . The infantry of the Greek left flank was commanded by the general Craterus , in a promotion from his position commanding a single brigade of pezhetairoi infantry at the Granicus . Things did not go well for the Macedonians in the beginning . Their center phalanx , having to advance across a river and up a fortified bank , suffered severely against the Greek mercenaries waiting for them on the other side . Arrian noted that a hundred and twenty Macedonians `` of note '' ( probably meaning officers ) were slain here , and the Macedonians were forced to retreat across the river . In the left flank , the Thessalian struggled against the outnumbering mass of Persian heavy horse that faced them , delivering charges and retreating again to buy time . Then the Hypaspists led by Alexander on foot delivered an assault on the Cardaces , and managed to punch a hole through the Persian line . The Agrianians too drove back a mass of Persian skirmishers menacing Alexander 's far right , securing the flank of the Companions . Alexander then mounted a horse at the head of his Companions and led a direct assault against Darius and his bodyguards , causing them to flee from the battlefield . Alexander then saw his left flank and center in trouble , and allowing Darius to flee , he crashed into the rear of the Greek mercenaries . The Greek mercenaries broke up and started retreating from the battlefield as well . The Persians saw that their Great King had gone and that the battle was being lost , and they abandoned their positions and fled in full rout . The Hellenic cavalry pursued the fleeing Persians for as long as there was light . As with most ancient battles , significant carnage occurred after the battle as the pursuing Greeks slaughtered their crowded , disorganized foe . Arrian notes Ptolemy mentioning that while pursuing Darius , Alexander and his bodyguards came upon a ravine which they easily crossed on the piled up bodies of dead Persians . It was a decisive victory for Alexander . Aftermath The family of Darius in front of Alexander , by Justus Sustermans and displayed in the Biblioteca Museu Víctor Balaguer The Battle of Issus was a decisive Hellenic victory and it marked the beginning of the end of Persian power . It was the first time the Persian army had been defeated with the King ( Darius III at the time ) present . After the battle , the Hellenes captured Darius ' wife , Stateira I , his daughters , Stateira II and Drypetis , and his mother , Sisygambis , all of whom had accompanied Darius on his campaign . Alexander , who later married Stateira II , treated the captured women with great respect . Depictions of the battle Altdorfer 's The Battle of Alexander at Issus German Renaissance painter and printmaker Albrecht Altdorfer ( c. 1480 -- 1538 ) dramatically depicted the battle in his 1529 painting The Battle of Alexander at Issus . The Battle of Issus ( c. 1599 -- 1600 ) by Jan Brueghel the Elder ( 1568 -- 1625 ) hangs in the Louvre . American Abstract Expressionist painter Cy Twombly diagrammed the battle in his 1968 painting Synopsis of a Battle . The 2004 Oliver Stone film Alexander was expected to depict the battle , instead , it put elements of the Battle of the Granicus , Issus , and Gaugamela all together . It was labeled as the Battle of Gaugamela but held distinctive elements of all three battles . The Battle of the Hydaspes River was also featured . Contemporary fine - artist Rossi d'Providence has created an oil painting of the Battle at Issus for the Classics Department at Brown University in Providence , Rhode Island . References Jump up ^ Warry ( 1998 ) estimates Alexander 's army to be 31,000 in total . ^ Jump up to : Moerbeek ( 1997 ) . Jump up ^ https://books.google.de/books?id=NECnIjWtIMEC&pg=PA241&lpg=PA241&dq=peltasts+ionia&source=bl&ots=g4Ng9S_6iC&sig=Jd8l5onclpgSsq8auD - ^ Jump up to : `` pothos.org - Major Battles '' . Archived from the original on 16 October 2007 . Retrieved 19 August 2016 . ^ Jump up to : Welman . Jump up ^ Curtius Rufus also tells that , except for about 4,500 wounded , 150 Macedonians were killed in action , and 302 were missing . This means that the army had lost about one tenth of its strength . `` Issus '' had been a hard fought victory . Jump up ^ Bibliotheca Historica . p. 17.33 -- 34 . first1 = missing last1 = in Authors list ( help ) Jump up ^ Heckel , W ( 1993 ) . The Marshalls of Alexander 's Empire . London . p. 109 . Jump up ^ `` Virginia Museum of Fine Arts - Richmond , Virginia '' . Retrieved 19 August 2016 . Jump up ^ Battle of Issus View the 275 cm × 120 cm ( 9 feet by 4 feet ) painting Archived January 16 , 2008 , at the Wayback Machine . Sources Ancient Diodorus Siculus ( 90 -- 30 BC ) . Bibliotheca Historica . ( Reference 6 ) Quintus Curtius Rufus ( AD 60 -- 70 ) . Historiae Alexandri Magni . Plutarch ( AD 75 ) . The Life of Alexander the Great , Parallel Lives . Arrian ( AD 86 -- 146 ) . Anabasis Alexandri . Junianus Justinus ( 3rd century ) . Historiarum Philippicarum libri XLIV . Modern Delbrück , Hans ( 1920 ) . History of the Art of War . University of Nebraska Press . Reprint edition , 1990 . Translated by Walter , J. Renfroe. 4 Volumes . Engels , Donald W. ( 1978 ) . Alexander the Great and the Logistics of the Macedonian Army . Berkeley / Los Angeles / London . Fuller , John F.C. ( 1960 ) . The Generalship of Alexander the Great . New Jersey : De Capo Press . Green , Peter ( 1974 ) . Alexander of Macedon : A Historical Biography . Moerbeek , Martijn ( 1997 ) . The battle of Issus , 333 BC . Universiteit Twente . Rogers , Guy ( 2004 ) . Alexander : The Ambiguity of Greatness . New York : Random House . Warry , J. ( 1998 ) , Warfare in the Classical World . ISBN 1 - 84065 - 004 - 4 . Welman , Nick . Army . Fontys University . External links Wikimedia Commons has media related to Battle of Issus . Livius.org : Modern - day photos around the former battle site Retrieved from `` https://en.wikipedia.org/w/index.php?title=Battle_of_Issus&oldid=836207844 '' Categories : 330s BC conflicts 333 BC Battles of Alexander the Great Battles involving the Achaemenid Empire History of Hatay Province Hidden categories : Wikipedia articles needing page number citations from September 2010 CS1 errors : missing author or editor Webarchive template wayback links Wikipedia semi-protected pages Coordinates on Wikidata All articles with unsourced statements Articles with unsourced statements from September 2016 Talk View source Contents About Wikipedia Azərbaycanca Български Bosanski Català Čeština Deutsch Ελληνικά Español Esperanto Euskara فارسی Français 한국어 Հայերեն हिन्दी Hrvatski Bahasa Indonesia Íslenska Italiano עברית ქართული Lietuvių Македонски मराठी Nederlands 日本 語 Norsk Occitan Polski Português Română Русский Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Türkçe Українська Tiếng Việt 中文 34 more Edit links This page was last edited on 13 April 2018 , at 10 : 12 . 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Question: where did the battle of issus take place


Pangaea - wikipedia Pangaea Jump to : navigation , search For other uses , see Pangaea ( disambiguation ) . Map of Pangaea with modern continental outlines Pangaea or Pangea ( / pænˈdʒiːə / ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras . It assembled from earlier continental units approximately 335 million years ago , and it began to break apart about 175 million years ago . In contrast to the present Earth and its distribution of continental mass , much of Pangaea was in the southern hemisphere and surrounded by a superocean , Panthalassa . Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists . Contents ( hide ) 1 Origin of the concept 2 Formation 3 Evidence of existence 4 Rifting and break - up 5 Tectonic plate shift 6 Life 7 Climate change after Pangaea 8 Implications of extinction 9 See also 10 References 11 External links Origin of the concept Life timeline view discuss edit - 4500 -- -- - 4000 -- -- - 3500 -- -- - 3000 -- -- - 2500 -- -- - 2000 -- -- - 1500 -- -- - 1000 -- -- - 500 -- -- 0 -- water Single - celled life photosynthesis Eukaryotes Multicellular life Land life Dinosaurs Mammals Flowers ← Earliest Earth ( − 4540 ) ← Earliest water ← Earliest life ← LHB meteorites ← Earliest oxygen ← Atmospheric oxygen ← Oxygen crisis ← Earliest sexual reproduction ← Ediacara biota ← Cambrian explosion ← Earliest humans h n r o z o i r o r o z o i r h n d n Pongola Huronian Cryogenian Andean Karoo Quaternary Axis scale : millions of years ago . Orange labels : ice ages . Also see : Human timeline and Nature timeline The name `` Pangaea / Pangea '' is derived from Ancient Greek pan ( πᾶν , `` all , entire , whole '' ) and Gaia ( Γαῖα , `` Mother Earth , land '' ) . The concept that the continents once formed a continuous land mass was first proposed by Alfred Wegener , the originator of the scientific theory of continental drift , in his 1912 publication The Origin of Continents ( Die Entstehung der Kontinente ) . He expanded upon his hypothesis in his 1915 book The Origin of Continents and Oceans ( Die Entstehung der Kontinente und Ozeane ) , in which he postulated that , before breaking up and drifting to their present locations , all the continents had formed a single supercontinent that he called the `` Urkontinent '' . The name `` Pangea '' occurs in the 1920 edition of Die Entstehung der Kontinente und Ozeane , but only once , when Wegener refers to the ancient supercontinent as `` the Pangaea of the Carboniferous '' . Wegener used the Germanized form `` Pangäa '' , but the name entered German and English scientific literature ( in 1922 and 1926 , respectively ) in the Latinized form `` Pangaea '' ( of the Greek `` Pangaia '' ) , especially due to a symposium of the American Association of Petroleum Geologists in November 1926 . Formation Appalachian orogeny The forming of supercontinents and their breaking up appears to have been cyclical through Earth 's history . There may have been many others before Pangaea . The fourth - last supercontinent , called Columbia or Nuna , appears to have assembled in the period 2.0 -- 1.8 Ga . Columbia / Nuna broke up and the next supercontinent , Rodinia , formed from the accretion and assembly of its fragments . Rodinia lasted from about 1.1 billion years ago ( Ga ) until about 750 million years ago , but its exact configuration and geodynamic history are not nearly as well understood as those of the later supercontinents , Pannotia and Pangaea . When Rodinia broke up , it split into three pieces : the supercontinent of Proto - Laurasia , the supercontinent of Proto - Gondwana , and the smaller Congo craton . Proto - Laurasia and Proto - Gondwana were separated by the Proto - Tethys Ocean . Next Proto - Laurasia itself split apart to form the continents of Laurentia , Siberia and Baltica . Baltica moved to the east of Laurentia , and Siberia moved northeast of Laurentia . The splitting also created two new oceans , the Iapetus Ocean and Paleoasian Ocean . Most of the above masses coalesced again to form the relatively short - lived supercontinent of Pannotia . This supercontinent included large amounts of land near the poles and , near the equator , only a relatively small strip connecting the polar masses . Pannotia lasted until 540 Ma , near the beginning of the Cambrian period and then broke up , giving rise to the continents of Laurentia , Baltica , and the southern supercontinent of Gondwana . In the Cambrian period , the continent of Laurentia , which would later become North America , sat on the equator , with three bordering oceans : the Panthalassic Ocean to the north and west , the Iapetus Ocean to the south and the Khanty Ocean to the east . In the Earliest Ordovician , around 480 Ma , the microcontinent of Avalonia -- a landmass incorporating fragments of what would become eastern Newfoundland , the southern British Isles , and parts of Belgium , northern France , Nova Scotia , New England , South Iberia and northwest Africa -- broke free from Gondwana and began its journey to Laurentia . Baltica , Laurentia , and Avalonia all came together by the end of the Ordovician to form a minor supercontinent called Euramerica or Laurussia , closing the Iapetus Ocean . The collision also resulted in the formation of the northern Appalachians . Siberia sat near Euramerica , with the Khanty Ocean between the two continents . While all this was happening , Gondwana drifted slowly towards the South Pole . This was the first step of the formation of Pangaea . The second step in the formation of Pangaea was the collision of Gondwana with Euramerica . By Silurian time , 440 Ma , Baltica had already collided with Laurentia , forming Euramerica . Avalonia had not yet collided with Laurentia , but as Avalonia inched towards Laurentia , the seaway between them , a remnant of the Iapetus Ocean , was slowly shrinking . Meanwhile , southern Europe broke off from Gondwana and began to move towards Euramerica across the newly formed Rheic Ocean . It collided with southern Baltica in the Devonian , though this microcontinent was an underwater plate . The Iapetus Ocean 's sister ocean , the Khanty Ocean , shrank as an island arc from Siberia collided with eastern Baltica ( now part of Euramerica ) . Behind this island arc was a new ocean , the Ural Ocean . By late Silurian time , North and South China split from Gondwana and started to head northward , shrinking the Proto - Tethys Ocean in their path and opening the new Paleo - Tethys Ocean to their south . In the Devonian Period , Gondwana itself headed towards Euramerica , causing the Rheic Ocean to shrink . In the Early Carboniferous , northwest Africa had touched the southeastern coast of Euramerica , creating the southern portion of the Appalachian Mountains , the Meseta Mountains and the Mauritanide Mountains . South America moved northward to southern Euramerica , while the eastern portion of Gondwana ( India , Antarctica and Australia ) headed toward the South Pole from the equator . North and South China were on independent continents . The Kazakhstania microcontinent had collided with Siberia . ( Siberia had been a separate continent for millions of years since the deformation of the supercontinent Pannotia in the Middle Carboniferous . ) Western Kazakhstania collided with Baltica in the Late Carboniferous , closing the Ural Ocean between them and the western Proto - Tethys in them ( Uralian orogeny ) , causing the formation of not only the Ural Mountains but also the supercontinent of Laurasia . This was the last step of the formation of Pangaea . Meanwhile , South America had collided with southern Laurentia , closing the Rheic Ocean and forming the southernmost part of the Appalachians and Ouachita Mountains . By this time , Gondwana was positioned near the South Pole and glaciers were forming in Antarctica , India , Australia , southern Africa and South America . The North China block collided with Siberia by Late Carboniferous time , completely closing the Proto - Tethys Ocean . By early Permian time , the Cimmerian plate split from Gondwana and headed towards Laurasia , thus closing the Paleo - Tethys Ocean , but forming a new ocean , the Tethys Ocean , in its southern end . Most of the landmasses were all in one . By the Triassic Period , Pangaea rotated a little and the Cimmerian plate was still travelling across the shrinking Paleo - Tethys , until the Middle Jurassic time . The Paleo - Tethys had closed from west to east , creating the Cimmerian Orogeny . Pangaea , which looked like a C , with the new Tethys Ocean inside the C , had rifted by the Middle Jurassic , and its deformation is explained below . Evidence of existence The distribution of fossils across the continents is one line of evidence pointing to the existence of Pangaea . Fossil evidence for Pangaea includes the presence of similar and identical species on continents that are now great distances apart . For example , fossils of the therapsid Lystrosaurus have been found in South Africa , India and Antarctica , alongside members of the Glossopteris flora , whose distribution would have ranged from the polar circle to the equator if the continents had been in their present position ; similarly , the freshwater reptile Mesosaurus has been found in only localized regions of the coasts of Brazil and West Africa . Additional evidence for Pangaea is found in the geology of adjacent continents , including matching geological trends between the eastern coast of South America and the western coast of Africa . The polar ice cap of the Carboniferous Period covered the southern end of Pangaea . Glacial deposits , specifically till , of the same age and structure are found on many separate continents which would have been together in the continent of Pangaea . Paleomagnetic study of apparent polar wandering paths also support the theory of a supercontinent . Geologists can determine the movement of continental plates by examining the orientation of magnetic minerals in rocks ; when rocks are formed , they take on the magnetic properties of the Earth and indicate in which direction the poles lie relative to the rock . Since the magnetic poles drift about the rotational pole with a period of only a few thousand years , measurements from numerous lavas spanning several thousand years are averaged to give an apparent mean polar position . Samples of sedimentary rock and intrusive igneous rock have magnetic orientations that are typically an average of the `` secular variation '' in the orientation of magnetic north because their remanent magnetizations are not acquired instantaneously . Magnetic differences between sample groups whose age varies by millions of years is due to a combination of true polar wander and the drifting of continents . The true polar wander component is identical for all samples , and can be removed , leaving geologists with the portion of this motion that shows continental drift and can be used to help reconstruct earlier continental positions . The continuity of mountain chains provides further evidence for Pangaea . One example of this is the Appalachian Mountains chain which extends from the southeastern United States to the Caledonides of Ireland , Britain , Greenland , and Scandinavia . Rifting and break - up Animation of the rifting of Pangaea There were three major phases in the break - up of Pangaea . The first phase began in the Early - Middle Jurassic ( about 175 Ma ) , when Pangaea began to rift from the Tethys Ocean in the east to the Pacific in the west . The rifting that took place between North America and Africa produced multiple failed rifts . One rift resulted in a new ocean , the North Atlantic Ocean . The Atlantic Ocean did not open uniformly ; rifting began in the north - central Atlantic . The South Atlantic did not open until the Cretaceous when Laurasia started to rotate clockwise and moved northward with North America to the north , and Eurasia to the south . The clockwise motion of Laurasia led much later to the closing of the Tethys Ocean and the widening of the `` Sinus Borealis '' , which later became the Arctic Ocean . Meanwhile , on the other side of Africa and along the adjacent margins of east Africa , Antarctica and Madagascar , new rifts were forming that would lead to the formation of the southwestern Indian Ocean that would open up in the Cretaceous . The second major phase in the break - up of Pangaea began in the Early Cretaceous ( 150 -- 140 Ma ) , when the minor supercontinent of Gondwana separated into multiple continents ( Africa , South America , India , Antarctica , and Australia ) . The subduction at Tethyan Trench probably caused Africa , India and Australia to move northward , causing the opening of a `` South Indian Ocean '' . In the Early Cretaceous , Atlantica , today 's South America and Africa , finally separated from eastern Gondwana ( Antarctica , India and Australia ) . Then in the Middle Cretaceous , Gondwana fragmented to open up the South Atlantic Ocean as South America started to move westward away from Africa . The South Atlantic did not develop uniformly ; rather , it rifted from south to north . Also , at the same time , Madagascar and India began to separate from Antarctica and moved northward , opening up the Indian Ocean . Madagascar and India separated from each other 100 -- 90 Ma in the Late Cretaceous . India continued to move northward toward Eurasia at 15 centimeters ( 6 in ) a year ( a plate tectonic record ) , closing the eastern Tethys Ocean , while Madagascar stopped and became locked to the African Plate . New Zealand , New Caledonia and the rest of Zealandia began to separate from Australia , moving eastward toward the Pacific and opening the Coral Sea and Tasman Sea . The third major and final phase of the break - up of Pangaea occurred in the early Cenozoic ( Paleocene to Oligocene ) . Laurasia split when North America / Greenland ( also called Laurentia ) broke free from Eurasia , opening the Norwegian Sea about 60 -- 55 Ma . The Atlantic and Indian Oceans continued to expand , closing the Tethys Ocean . Meanwhile , Australia split from Antarctica and moved quickly northward , just as India had done more than 40 million years before . Australia is currently on a collision course with eastern Asia . Both Australia and India are currently moving northeast at 5 -- 6 centimeters ( 2 -- 3 in ) a year . Antarctica has been near or at the South Pole since the formation of Pangaea about 280 Ma . India started to collide with Asia beginning about 35 Ma , forming the Himalayan orogeny , and also finally closing the Tethys Seaway ; this collision continues today . The African Plate started to change directions , from west to northwest toward Europe , and South America began to move in a northward direction , separating it from Antarctica and allowing complete oceanic circulation around Antarctica for the first time . This motion , together with decreasing atmospheric carbon dioxide concentrations , caused a rapid cooling of Antarctica and allowed glaciers to form . This glaciation eventually coalesced into the kilometers - thick ice sheets seen today . Other major events took place during the Cenozoic , including the opening of the Gulf of California , the uplift of the Alps , and the opening of the Sea of Japan . The break - up of Pangaea continues today in the Red Sea Rift and East African Rift . Tectonic plate shift The breakup of Pangaea over time Pangaea 's formation is now commonly explained in terms of plate tectonics . The involvement of plate tectonics in Pangaea 's separation helps to show how it did not separate all at once , but at different times , in sequences . Additionally , after these separations , it has also been discovered that the separated land masses may have also continued to break apart multiple times . The formation of each environment and climate on Pangaea is due to plate tectonics , and thus , it is as a result of these shifts and changes different climatic pressures were placed on the life on Pangaea . Although plate tectonics was paramount in the formation of later land masses , it was also essential in the placement , climate , environments , habitats , and overall structure of Pangaea . What can also be observed in relation to tectonic plates and Pangaea , is the formations to such plates . Mountains and valleys form due to tectonic collisions as well as earthquakes and chasms . Consequentially , this shaped Pangaea and animal adaptations . Furthermore , plate tectonics can contribute to volcanic activity , which is responsible for extinctions and adaptations which have evidently affected life over time , and without doubt on Pangaea . Life Example of an ammonite For the approximately 160 million years Pangaea existed , many species had fruitful times whereas others struggled . The Traversodontidae is an example of such prospering animals , eating a diet of only plants . Plants dependent on spore reproduction had been taken out of the ecosystems , and replaced by the gymnosperm plant , which reproduces through the use of seeds instead . Later on , insects ( beetles , dragonflies , mosquitos ) also thrived during the Permian period 299 to 252 million years ago . However , the Permian extinction at 252 Mya greatly impacted these insects in mass extinction , being the only mass extinction to affect insects . When the Triassic Period came , many reptiles were able to also thrive , including Archosaurs , which were an ancestor to modern - day crocodiles and birds . Little is known about marine life during the existence of Pangaea . Scientists are unable to find substantial evidence or fossilized remains in order to assist them in answering such questions . However , a couple of marine animals have been determined to have existed at the time - the Ammonites and Brachiopods . Additionally , evidence pointing towards massive reefs with varied ecosystems , especially in the species of sponges and coral , have also been discovered . Climate change after Pangaea Pangaea has tremendously affected the setup of the world now . In the post Pangaea time period , the reconfiguration of continents and oceans has changed the climate of many areas . There is scientific evidence that proves that climate was drastically altered . When the continents separated and reformed themselves , it changed the flow of the oceanic currents and winds . The scientific reasoning behind all of the changes is Continental Drift . The theory of Continental Drift , created by Alfred Wegener , explained how the continents shifted Earth 's surface and how that affected many aspects such as climate , rock formations found on different continents and plant and animal fossils . Wegener studied plant fossils from the frigid Arctic of Svalbard , Norway . He determined that such plants were not meant to adapt to a glacial climate . The fossils he found were from tropical plants that were meant to adapt and thrive in warmer and tropical climate . Because we would not assume that the plant fossils were capable of traveling to a different place we suspect that Svalbard possibly had a warmer , less frigid climate in the past . When Pangaea separated , the reorganization of the continents changed the function of the oceans and seaways . The restructuring of the continents , changed and altered the distribution of warmth and coolness of the oceans . When North America and South America connected , it stopped equatorial currents from passing from the Atlantic Ocean to the Pacific Ocean . Researchers have found evidence by using computer hydrological models to show that this strengthened the Gulf Stream by diverting more warm currents towards Europe . Warm waters at high latitudes led to an increased evaporation and eventually atmospheric moisture . Increased evaporation and atmospheric moisture resulted in increased precipitation . Evidence of increased precipitation is the development of snow and ice that covers Greenland , which led to an accumulation of the icecap . Greenland 's growing ice cap led to further global cooling . Scientists also found evidence of global cooling through the separation of Australia and Antarctica and the formation of the Antarctic Ocean . Ocean currents in the newly formed Antarctic or Southern Ocean created a circumpolar current . The creation of the new ocean that caused a circumpolar current eventually led to atmospheric currents that rotated from west to east . Atmospheric and oceanic currents stopped the transfer of warm , tropical air and water to the higher latitudes . As a result of the warm air and currents moving northward , Antarctica cooled down so much that it became frigid . Although many of Alfred Wegener 's theories and conclusions were valid , scientists are constantly coming up with new innovative ideas or reasoning behind why certain things happen . Wegener 's theory of Continental Drift was later replaced by the theory of tectonic plates . Implications of extinction There is evidence to suggest that the deterioration of northern Pangaea contributed to the Permian Extinction , one of Earth 's five major mass extinction events , which resulted in the loss of over 90 % of marine and 70 % of terrestrial species . There were three main sources of environmental deterioration which are believed to have had a hand in the extinction event . The first of these sources is a loss of oxygen concentration in the ocean which caused deep water regions called the lysocline to grow shallower . With the lysocline shrinking , there were fewer places for calcite to dissolve in the ocean , considering calcite only dissolves at deep ocean depths . This led to the extinction of carbonate producers such as brachiopods and corals that relied on dissolved calcite to survive . The second source is the eruption of the Siberian Traps , a large volcanic event which is argued to be the result of Pangaean tectonic movement . This had several negative repercussions on the environment , including metal loading and excess atmospheric carbon . Metal loading , the release of toxic metals from volcanic eruptions into the environment , led to acid rain and general stress on the environment . These toxic metals are known to infringe on vascular plants ' ability to photosynthesize , which may have resulted in the loss of Permian - era flora . Excess carbon dioxide in the atmosphere is believed to be the main cause of the shrinking of lysocline areas . The third cause of this extinction event that can be attributed to northern Pangaea is the beginnings of anoxic ocean environments , or oceans with very low oxygen concentrations . The mix of anoxic oceans and ocean acidification due to metal loading led to increasingly acidic oceans , which ultimately led to the extinction of Benthos . See also Africa portal Antarctica portal Asia portal Australia portal Europe portal North America portal South America portal History of the Earth List of supercontinents Potential future supercontinents : Pangaea Ultima , Novopangaea & Amasia PANGAEA , a data library for earth system science , operated by the Alfred Wegener Institute for Polar and Marine Research ( AWI ) Supercontinent cycle References Jump up ^ Oxford Dictionaries Jump up ^ Lovett , Richard A. ( September 5 , 2008 ) . `` Supercontinent Pangaea Pushed , Not Sucked , Into Place '' . National Geographic News . Jump up ^ `` Pangea '' . Encyclopædia Britannica Inc. 2015 . Jump up ^ Rogers , J.J.W. ; Santosh , M. ( 2004 ) , Continents and Supercontinents , Oxford : Oxford University Press , p. 146 , ISBN 0 - 19 - 516589 - 6 Jump up ^ `` Pangaea '' . Online Etymology Dictionary . Jump up ^ Vergilius Mario , Publius . Georgicon , IV. 462 Jump up ^ Lucan . Pharsalia , I. 679 Jump up ^ Lewis , C.T. & al. `` Pangaeus '' in A Latin Dictionary . ( New York ) , 1879 . Jump up ^ Usener , H. Scholia in Lucani Bellum Civile , Vol . I. ( Leipzig ) , 1869 . Jump up ^ As `` Pangaea '' , it appears in Greek mythology as a mountain battle site during the Titanomachia . As `` Pangaeus '' , it was the name of a specific mountain range in southern Thrace . `` Pangaea '' also appears in Vergil 's Georgics and Lucan 's Pharsalia The scholiast on Lucan glossed Pangaea id est totum terra -- `` Pangaea : that is , all land '' -- as having received its name on account of its smooth terrain and unexpected fertility . Jump up ^ Alfred Wegener : Die Entstehung der Kontinente . Dr. A. Petermann 's Mitteilungen aus Justus Perthes ' Geographischer Anstalt , 58 ( 1 ) : Gotha 1912 Jump up ^ See : Wegener , Alfred , Die Entstehung der Kontinente und Ozeane , 2nd ed . ( Braunschweig , Germany : F. Vieweg , 1920 ) , p. 120 : `` Schon die Pangäa der Karbonzeit hatte so einen Vorderrand ... '' ( Already the Pangea of the Carboniferous era had such a leading edge ... ) ( In the 1922 edition , see p. 130 . ) Wegener , A. ; Krause , R. ; Thiede , J. ( 2005 ) . `` Kontinental - Verschiebungen : Originalnotizen und Literaturauszüge '' ( Continental drift : the original notes and quotations ) . Berichte zur Polar - und Meeresforschung ( Reports on Polar and Marine Research ) 516 . Alfred - Wegener - Institut : Bremerhaven , p. 4 , n . 2 Jump up ^ Jaworski , Erich ( 1922 ) . `` Die A. Wegenersche Hypothese der Kontinentalverschiebung '' . Geologische Rundschau. 13 : 273 -- 296 . doi : 10.1007 / bf01799790 . Jump up ^ Willem A.J.M. van Waterschoot van der Gracht ( and 13 other authors ) : Theory of Continental Drift : a Symposium of the Origin and Movements of Land - masses of both Inter-Continental and Intra-Continental , as proposed by Alfred Wegener . X + 240 S. , Tulsa , Oklahoma , USA , The American Association of Petroleum Geologists & London , Thomas Murby & Co . Jump up ^ Zhao , Guochun ; Cawood , Peter A. ; Wilde , Simon A. ; Sun , M. ( 2002 ) . `` Review of global 2.1 -- 1.8 Ga orogens : implications for a pre-Rodinia supercontinent '' . Earth - Science Reviews . 59 : 125 -- 162 . Bibcode : 2002ESRv ... 59 ... 125Z . doi : 10.1016 / S0012 - 8252 ( 02 ) 00073 - 9 . Jump up ^ Zhao , Guochun ; Sun , M. ; Wilde , Simon A. ; Li , S.Z. ( 2004 ) . `` A Paleo - Mesoproterozoic supercontinent : assembly , growth and breakup '' . Earth - Science Reviews . 67 : 91 -- 123 . doi : 10.1016 / j. earscirev. 2004.02. 003 . Jump up ^ Stanley , Steven ( 1998 ) . Earth System History . USA . pp. 355 -- 359 . Jump up ^ Stanley , Steven ( 1998 ) . Earth System History . USA . pp. 386 -- 392 . Jump up ^ Benton , M.J. ( 2005 ) Vertebrate Palaeontology . Third edition , Oxford , p. 25 . Jump up ^ Murck , Barbara W. and Skinner , Brian J. ( 1999 ) Geology Today : Understanding Our Planet , Study Guide , Wiley , ISBN 978 - 0 - 471 - 32323 - 5 Jump up ^ Kearey , Philip ; Klepeis , Keith A. and Vine , Frederick J. ( 2009 ) . Global Tectonics ( 3rd . ed ) , pp. 66 -- 67 . Chichester : Wiley . ISBN 978 - 1 - 4051 - 0777 - 8 ^ Jump up to : Merali , Zeeya and Skinner , Brian J. ( 2009 ) Visualizing Earth Science , Wiley , ISBN 047174705X Jump up ^ Deconto , Robert M. ; Pollard , David ( 2003 ) . `` Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO '' . Nature . 421 ( 6920 ) : 245 -- 9 . doi : 10.1038 / nature01290 . PMID 12529638 . Jump up ^ `` Pangea supercontinent '' . Encyclopædia Britannica . Retrieved 2015 - 10 - 29 . Jump up ^ `` Facts About Pangaea , Ancient Supercontinent '' . LiveScience.com . Retrieved 2015 - 10 - 29 . Jump up ^ `` Pangaea to the Present Lesson # 2 Volcano World Oregon State University '' . volcano.oregonstate.edu . Retrieved 2015 - 10 - 29 . Jump up ^ Ranivoharimanana , Lovasoa ; Kammerer , Christian F. ; Flynn , John J. ; Wyss , André R. ( 2011 ) . `` New material of Dadadon isaloi ( Cynodontia , Traversodontidae ) from the Triassic of Madagascar '' . Journal of Vertebrate Paleontology. 31 ( 6 ) : 1292 -- 1302 . doi : 10.1080 / 02724634.2011. 618154 . Jump up ^ `` Permian Period : Climate , Animals & Plants '' . LiveScience.com . Retrieved 2015 - 10 - 29 . Jump up ^ `` Alfred Wegener '' . www.ucmp.berkeley.edu . Retrieved 2015 - 10 - 29 . Jump up ^ Tabor , Neil J. ; Poulsen , Christopher J. ( 2008 ) . `` Palaeoclimate across the Late Pennsylvanian -- Early Permian tropical palaeolatitudes : A review of climate indicators , their distribution , and relation to palaeophysiographic climate factors '' . Palaeogeography , Palaeoclimatology , Palaeoecology. 268 ( 3 -- 4 ) : 293 -- 310 . doi : 10.1016 / j. palaeo. 2008.03. 052 . Jump up ^ `` continental drift '' . National Geographic Education . Retrieved 2015 - 10 - 29 . ^ Jump up to : `` Sea Level Change '' . cgge.aag.org . Retrieved 2015 - 10 - 29 . Jump up ^ `` Continental Drift : Theory & Definition '' . LiveScience.com . Retrieved 2015 - 10 - 29 . Jump up ^ Ivanov , A.V. ( 2007 ) . `` Evaluation of different models for the origin of the Siberian traps '' . GSA Special Papers. 430 : 669 -- 691 . doi : 10.1130 / 2007.2430 ( 31 ) . ISBN 978 - 0 - 8137 - 2430 - 0 . Jump up ^ Beauchamp , Benoit ; Grasby , Stephen E. ( 2012 ) . `` Permian lysocline shoaling and ocean acidification along NW Pangea led to carbonate eradication and chert expansion '' . Palaeogeography , Palaeoclimatology , Palaeoecology. 350 -- 352 : 73 -- 90 . doi : 10.1016 / j. palaeo. 2012.06. 014 . Jump up ^ Grasby , Stephen E. ; Beauchamp , Benoit ; Bond , David P.G. ; Wignall , Paul ; Talavera , Cristina ; Galloway , Jennifer M. ; Piepjohn , Karsten ; Reinhardt , Lutz ; Blomeier , Dierk ( 2015 ) . `` Progressive environmental deterioration in northwestern Pangea leading to the latest Permian extinction '' . Geological Society of America Bulletin . 127 ( 9 -- 10 ) : 1331 -- 1347 . doi : 10.1130 / B31197. 1 . External links Wikimedia Commons has media related to Pangaea . Look up Pangaea in Wiktionary , the free dictionary . USGS Overview Map of Triassic Pangaea at Paleomaps NHM Gallery ( hide ) Continents of the World Africa Antarctica Asia Australia Europe North America South America Afro - Eurasia America Eurasia Oceania Former supercontinents Gondwana Laurasia Pangaea Pannotia Rodinia Columbia Kenorland Nena Sclavia Ur Vaalbara Historical continents Amazonia Arctica Asiamerica Atlantica Avalonia Baltica Cimmeria Congo craton Euramerica Kalaharia Kazakhstania Laurentia North China Siberia South China East Antarctica India Submerged continents Kerguelen Plateau Zealandia Possible future supercontinents Pangaea Ultima Amasia Novopangaea Mythical and hypothesised continents Atlantis Kumari Kandam Lemuria Meropis Mu Hyperborea Terra Australis See also Regions of the world Continental fragment Book BNF : cb12500043k ( data ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Pangaea&oldid=816082317 '' Categories : Geological history of Earth Historical continents Carboniferous paleogeography Permian paleogeography Triassic paleogeography Jurassic paleogeography Plate tectonics Supercontinents Hidden categories : Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move - protected pages Articles containing Ancient Greek - language text All articles with unsourced statements Articles with unsourced statements from March 2017 Wikipedia articles with BNF identifiers Talk View source Contents About Wikipedia Afrikaans Asturianu Azərbaycanca বাংলা Башҡортса Беларуская Беларуская ( тарашкевіца )  Български Bosanski Brezhoneg Català Cebuano Čeština Cymraeg Dansk Deutsch ދިވެހިބަސް Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Gàidhlig Galego 한국어 हिन्दी Hrvatski Bahasa Indonesia Íslenska Italiano עברית Basa Jawa ქართული Қазақша Kiswahili Kreyòl ayisyen Latina Latviešu Lëtzebuergesch Lietuvių Magyar Македонски മലയാളം Malti मराठी მარგალური Bahasa Melayu Nederlands 日本 語 Nordfriisk Norsk Norsk nynorsk Occitan ਪੰਜਾਬੀ پنجابی Piemontèis Polski Português Română Русский Scots Shqip Sicilianu Simple English Slovenčina Slovenščina Soomaaliga Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Tagalog தமிழ் Татарча / tatarça ไทย Türkçe Українська اردو Tiếng Việt Walon 文言 Winaray 粵語 Zazaki 中文 Edit links This page was last edited on 19 December 2017 , at 04 : 03 . 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Question: what land mass was north america a part of about 300 million years ago


Cell division - wikipedia Cell division Jump to : navigation , search Not to be confused with cellular differentiation . Three types of cell division Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division usually occurs as part of a larger cell cycle . In eukaryotes , there are two distinct types of cell division : a vegetative division , whereby each daughter cell is genetically identical to the parent cell ( mitosis ) , and a reproductive cell division , whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes ( meiosis ) . Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions . Homologous chromosomes are separated in the first division , and sister chromatids are separated in the second division . Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle . Both are believed to be present in the last eukaryotic common ancestor . Prokaryotes undergo a vegetative cell division known as binary fission , where their genetic material is segregated equally into two daughter cells . All cell divisions , regardless of organism , are preceded by a single round of DNA replication . For simple unicellular microorganisms such as the amoeba , one cell division is equivalent to reproduction -- an entire new organism is created . On a larger scale , mitotic cell division can create progeny from multicellular organisms , such as plants that grow from cuttings . Mitotic cell division enables sexually reproducing organisms to develop from the one - celled zygote , which itself was produced by meiotic cell division from gametes . After growth , cell division by mitosis allows for continual construction and repair of the organism . The human body experiences about 10 quadrillion cell divisions in a lifetime . The primary concern of cell division is the maintenance of the original cell 's genome . Before division can occur , the genomic information that is stored in chromosomes must be replicated , and the duplicated genome must be separated cleanly between cells . A great deal of cellular infrastructure is involved in keeping genomic information consistent between generations . Contents ( hide ) 1 Phases of cell division 1.1 Interphase 1.2 Prophase 1.3 Metaphase 1.4 Anaphase 1.5 Telophase 2 Variants 3 Degradation 4 History 5 See also 6 References 7 Further reading 8 External links Phases of cell division ( edit ) This article relies too much on references to primary sources . Please improve this by adding secondary or tertiary sources . ( July 2017 ) ( Learn how and when to remove this template message ) Interphase ( edit ) Interphase is the process a cell must go through before mitosis , meiosis , and cytokinesis . Interphase consists of four main stages : G1 , S , G0 , and G2 . G1 is a time of growth for the cell . If the cell does not progress through G1 , the cell then enters a stage called G0 . In G0 , cells are still living but they are put on hold . The cells may later be called back into interphase if needed at a later time . There are checkpoints during interphase that allow the cell to be either progressed or denied further development . In S phase , the chromosomes are replicated in order for the genetic content to be maintained . During G2 , the cell undergoes the final stages of growth before it enters the M phase . The M phase , can be either mitosis or meiosis depending on the type of cell . Germ cells undergo meiosis , while somatic cells will undergo mitosis . After the cell proceeds successfully through the M phase , it may then undergo cell division through cytokinesis . The control of each checkpoint is controlled by cyclin and cyclin dependent kinases . The progression of interphase is the result of the increased amount of cyclin . As the amount of cyclin increases , more and more cyclin dependent kinases attach to cyclin signaling the cell further into interphase . The peak of the cyclin attached to the cyclin dependent kinases this system pushes the cell out of interphase and into the M phase , where mitosis , meiosis , and cytokinesis occur . Prophase ( edit ) Prophase is the first stage of division . The nuclear envelope is broken down , long strands of chromatin condense to form shorter more visible strands called chromosomes , the nucleolus disappears , and microtubules attach to the chromosomes at the kinetochores present in the centromere . Microtubules associated with the alignment and separation of chromosomes are referred to as the spindle and spindle fibers . Chromosomes will also be visible under a microscope and will be connected at the centromere . During this condensation and alignment period , homologous chromosomes may swap portions of their DNA in a process known as crossing over . Metaphase ( edit ) Metaphase is the stage in cell division when the chromosomes line up in the middle of the cell by MTOCs ( microtubule organizing center ) by pushing and pulling on centromeres of both chromatids which causes the chromosome to move to the center . The chromosomes are still condensing and are currently at one step away from being the most coiled and condensed they will be . Spindle and spindle fibers have already connected to the kinetochores . At this point , the chromosomes are ready to split into opposite poles of the cell towards the spindle to which they are connected . Anaphase ( edit ) Anaphase is a very short stage of the cell cycle and occurs after the chromosomes align at the mitotic plate . After the chromosomes line up in the middle of the cell , the spindle fibers will pull them apart . The chromosomes are split apart as the sister chromatids move to opposite sides of the cell . Telophase ( edit ) Telophase is the last stage of the cell cycle . Two cells form around the chromatin at the two poles of the cell . Two nuclear membranes begin to reform and the chromatin begin to unwind . Variants ( edit ) Image of the mitotic spindle in a human cell showing microtubules in green , chromosomes ( DNA ) in blue , and kinetochores in red . Cells are broadly classified into two main categories : simple , non-nucleated prokaryotic cells , and complex , nucleated eukaryotic cells . Owing to their structural differences , eukaryotic and prokaryotic cells do not divide in the same way . Also , the pattern of cell division that transforms eukaryotic stem cells into gametes ( sperm cells in males or egg cells in females ) , termed meiosis , is different from that of the division of somatic cells in the body . Cell division over 42 . The cells were directly imaged in the cell culture vessel , using non-invasive quantitative phase contrast time - lapse microscopy . Degradation ( edit ) Multicellular organisms replace worn - out cells through cell division . In some animals , however , cell division eventually halts . In humans this occurs , on average , after 52 divisions , known as the Hayflick limit . The cell is then referred to as senescent . Cells stop dividing because the telomeres , protective bits of DNA on the end of a chromosome required for replication , shorten with each copy , eventually being consumed . Cancer cells , on the other hand , are not thought to degrade in this way , if at all . An enzyme called telomerase , present in large quantities in cancerous cells , rebuilds the telomeres , allowing division to continue indefinitely . History ( edit ) A cell division under microscope was first discovered by German botanist Hugo von Mohl in 1835 as he worked over Green algae Cladophora glomerata . See also ( edit ) Binary fission Cell growth Labile cells , cells that constantly divide Klerokinesis References ( edit ) Jump up ^ Robert. S Hine , ed. ( 2008 ) . Oxford Dictionary Biology ( 6th ed . ) . New York : Oxford University Press . p. 113 . ISBN 978 - 0 - 19 - 920462 - 5 . Jump up ^ Griffiths , Anthony J.F. ; Wessler , Susan R. ; Carroll , Sean B. ; Doebley , John ( 2012 ) . Introduction to Genetic Analysis ( 10 ed . ) . New York : W.H. Freeman and Company . p. 35 . ISBN 978 - 1 - 4292 - 2943 - 2 . Jump up ^ Maton , Anthea ( 1997 ) . Cells : Building Blocks of Life . New Jersey : Prentice Hall . pp. 70 -- 74 . ISBN 0 - 13 - 423476 - 6 . Jump up ^ Quammen , David ( April 2008 ) . `` Contagious cancer : The evolution of a killer '' . Harper 's . 316 ( 1895 ) : 42 . Retrieved 24 September 2012 . Jump up ^ Marieb , Elaine ( 2000 ) . Essentials of human anatomy and physiology . San Francisco : Benjamin Cummings . ISBN 0 - 8053 - 4940 - 5 . Jump up ^ Schermelleh , Lothar ; Carlton , Peter M. ; Haase , Sebastian ; Shao , Lin ; Winoto , Lukman ; Kner , Peter ; Burke , Brian ; Cardoso , M. Cristin ; Agard , David A. ( 2008 - 06 - 06 ) . `` Subdiffraction Multicolor Imaging of the Nuclear Periphery with 3D Structured Illumination Microscopy '' . Science . 320 ( 5881 ) : 1332 -- 1336 . doi : 10.1126 / science. 1156947 . ISSN 0036 - 8075 . PMC 2916659 . PMID 18535242 . Jump up ^ `` Researchers Shed Light On Shrinking Of Chromosomes '' . ScienceDaily . June 12 , 2007 . Retrieved 2017 - 02 - 02 . Jump up ^ Elrod , Susan ( 2002 ) . Schaum 's Outline of Genetics ( Fifth ed . ) . United States of America : McGraw - Hill Companies , Inc. p. 8 . ISBN 9780071625036 . Jump up ^ `` The Cell Cycle '' . www.biology-pages.info . Retrieved 2017 - 02 - 02 . Jump up ^ Hetzer , Martin W. ( 2017 - 02 - 02 ) . `` The Nuclear Envelope '' . Cold Spring Harbor Perspectives in Biology . 2 ( 3 ) . doi : 10.1101 / cshperspect. a000539 . ISSN 1943 - 0264 . PMC 2829960 . PMID 20300205 . Jump up ^ Phase Holographic Imaging . Cell Division Jump up ^ Karl Mägdefrau ( 1994 ) , `` Mohl , Hugo von '' , Neue Deutsche Biographie ( NDB ) ( in German ) , 17 , Berlin : Duncker & Humblot , pp. 690 -- 691 ; ( full text online ) Further reading ( edit ) Morgan HI. ( 2007 ) . `` The Cell Cycle : Principles of Control '' London : New Science Press . J.M. Turner Fetus into Man ( 1978 , 1989 ) . Harvard University Press . ISBN 0 - 674 - 30692 - 9 Cell division : binary fission and mitosis External links ( edit ) Wikimedia Commons has media related to Cell division . How Cells Divide : Mitosis vs. Meiosis The Mitosis and Cell Cycle Control Section from the Landmark Papers in Cell Biology ( Gall JG , McIntosh JR , eds . ) contains commentaries on and links to seminal research papers on mitosis and cell division . Published online in the Image & Video Library of The American Society for Cell Biology The Image & Video Library of The American Society for Cell Biology contains many videos showing the cell division . Videos of the first cell divisions in Xenopus laevis embryos ( side view and top view ) , acquired by MRI ( DOI of paper ) Images : Calanthe discolor Lindl . - Flavon 's Secret Flower Garden Tyson 's model of cell division and a Description on BioModels Database WormWeb.org : Interactive Visualization of the C. elegans Cell Lineage - Visualize the entire set of cell divisions of the nematode C. elegans ( hide ) Cell cycle proteins Cyclin A ( A1 , A2 ) B ( B1 , B2 , B3 ) D ( D1 , D2 , D3 ) E ( E1 , E2 ) CDK 5 6 7 8 9 10 CDK - activating kinase CDK inhibitor INK4a / ARF ( p14arf / p16 , p15 , p18 , p19 ) cip / kip ( p21 , p27 , p57 ) P53 p63 p73 family p53 p63 p73 Other Cdc2 Cdc25 Cdc42 Cellular apoptosis susceptibility protein E2F Maturation promoting factor Wee Cullin ( CUL7 ) Phases and checkpoints Interphase G phase S phase G phase M phase Mitosis ( Preprophase Prophase Prometaphase Metaphase Anaphase Telophase ) Cytokinesis Cell cycle checkpoints Restriction point Spindle checkpoint Postreplication checkpoint Other cellular phases Apoptosis G phase Meiosis GND : 4190668 - 8 NDL : 00569966 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Cell_division&oldid=821867695 '' Categories : Cell cycle Cellular processes Telomeres 1835 in science Hidden categories : CS1 German - language sources ( de ) Wikipedia pages move - protected due to vandalism Articles lacking reliable references from July 2017 All articles lacking reliable references All articles with unsourced statements Articles with unsourced statements from October 2016 Wikipedia articles with GND identifiers Talk Variants Contents About Wikipedia Azərbaycanca বাংলা Bosanski Català Čeština Cymraeg Dansk Deutsch Ελληνικά Español Euskara فارسی Français Gaeilge Galego 한국어 Հայերեն हिन्दी Hrvatski Bahasa Indonesia IsiXhosa Íslenska Italiano עברית ಕನ್ನಡ Қазақша Lietuvių Македонски മലയാളം Bahasa Melayu Nederlands 日本 語 Norsk Norsk nynorsk Oʻzbekcha / ўзбекча پښتو Polski Português Русский Scots Simple English Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska Tagalog தமிழ் ไทย Türkçe Українська اردو Tiếng Việt 中文 Edit links This page was last edited on 23 January 2018 , at 02 : 24 . 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Question: who discovered cells divide to make new cells


Glycogenin - wikipedia Glycogenin Jump to : navigation , search glycogenin glucosyltransferase Glycogenin structure ( from rabbit ) . Identifiers EC number 2.4. 1.186 CAS number 117590 - 73 - 5 Databases IntEnz IntEnz view BRENDA BRENDA entry ExPASy NiceZyme view KEGG KEGG entry MetaCyc metabolic pathway PRIAM profile PDB structures RCSB PDB PDBe PDBsum ( show ) Search PMC articles PubMed articles NCBI proteins Glycogenin is an enzyme involved in converting glucose to glycogen . It acts as a primer , by polymerizing the first few glucose molecules , after which other enzymes take over . It is a homodimer of 37 - kDa subunits and is classified as a glycosyltransferase . It catalyzes the chemical reaction : UDP - alpha - D - glucose + glycogenin ⇌ ( \ displaystyle \ rightleftharpoons ) UDP + alpha - D - glucosylglycogenin Thus , the two substrates of this enzyme are UDP - alpha - D - glucose and glycogenin , whereas its two products are UDP and alpha - D - glucosylglycogenin . Contents ( hide ) 1 Nomenclature 2 Discovery 3 Function 4 Structure 5 Isozymes 6 References 7 Further reading 8 External links Nomenclature ( edit ) This enzyme belongs to the family of glycosyltransferases , specifically the hexosyltransferases . The systematic name of this enzyme class is UDP - alpha - D - glucose : glycogenin alpha - D - glucosyltransferase . Other names in common use include : glycogenin , priming glucosyltransferase , and UDP - glucose : glycogenin glucosyltransferase . Discovery ( edit ) Glycogenin was discovered in 1984 by Dr. William J. Whelan , a fellow of the Royal Society of London and current professor of Biochemistry at the University of Miami . Function ( edit ) The main enzyme involved in glycogen polymerisation , glycogen synthase , can only add to an existing chain of at least 4 glucose residues . Glycogenin acts as the primer , to which further glucose monomers may be added . It achieves this by catalyzing the addition of glucose to itself ( autocatalysis ) by first binding glucose from UDP - glucose to the hydroxyl group of Tyr - 194 . Seven more glucoses can be added , each derived from UDP - glucose , by glycogenin 's glucosyltransferase activity . Once sufficient residues have been added , glycogen synthase takes over extending the chain . Glycogenin remains covalently attached to the reducing end of the glycogen molecule . Evidence accumulates that a priming protein may be a fundamental property of polysaccharide synthesis in general ; the molecular details of mammalian glycogen biogenesis may serve as a useful model for other systems . Structure ( edit ) 2 - D cross-sectional view of glycogen . A core protein of glycogenin is surrounded by branches of glucose units . The entire globular complex may contain approximately 30 000 glucose units . Isozymes ( edit ) In humans , there are two isoforms of glycogenin -- glycogenin - 1 , encoded by GYG1 , and expressed in muscle ; and glycogenin - 2 , encoded by GYG2 , and expressed in the liver and cardiac muscle , but not skeletal muscle . Patients have been found with defective GYG1 , resulting in muscle cells with the inability to store glycogen , and consequential weakness and heart disease . glycogenin 1 Identifiers Symbol GYG1 Alt . symbols GYG Entrez 2992 HUGO 4699 OMIM 603942 RefSeq NM_004130 UniProt P46976 Other data EC number 2.4. 1.186 Locus Chr. 3 q24 - q25. 1 glycogenin 2 Identifiers Symbol GYG2 Entrez 8908 HUGO 4700 OMIM 300198 RefSeq NM_003918 UniProt O15488 Other data EC number 2.4. 1.186 Locus Chr . X p22. 3 References ( edit ) Jump up ^ PDB : 1LL3  ; Gibbons BJ , Roach PJ , Hurley TD ( May 2002 ) . `` Crystal structure of the autocatalytic initiator of glycogen biosynthesis , glycogenin '' . J. Mol. Biol. 319 ( 2 ) : 463 -- 77 . PMID 12051921 . doi : 10.1016 / S0022 - 2836 ( 02 ) 00305 - 4 . Jump up ^ Whelan WJ ( September 1998 ) . `` Pride and prejudice : the discovery of the primer for glycogen synthesis '' . Protein Sci. 7 ( 9 ) : 2038 -- 41 . PMC 2144155 . PMID 9761486 . doi : 10.1002 / pro. 5560070921 . Jump up ^ Katch , Victor L. ; McArdle , William D. ; Katch , Frank I. ( 2007 ) . Exercise physiology : energy , nutrition , and human performance . Philadelphia : Lippincott Williams and Wilkins . p. 12 . ISBN 0 - 7817 - 4990 - 5 . Jump up ^ Moslemi AR , Lindberg C , Nilsson J , Tajsharghi H , Andersson B , Oldfors A ( April 2010 ) . `` Glycogenin - 1 deficiency and inactivated priming of glycogen synthesis '' . N. Engl. J. Med. 362 ( 13 ) : 1203 -- 10 . PMID 20357282 . doi : 10.1056 / NEJMoa0900661 . Further reading ( edit ) Krisman CR , Barengo R ( 1975 ) . `` A precursor of glycogen biosynthesis : alpha - 1 , 4 - glucan - protein '' . Eur. J. Biochem. 52 ( 1 ) : 117 -- 23 . PMID 809265 . doi : 10.1111 / j. 1432 - 1033.1975. tb03979. x . Pitcher J , Smythe C , Campbell DG , Cohen P ( 1987 ) . `` Identification of the 38 - kDa subunit of rabbit skeletal muscle glycogen synthase as glycogenin '' . Eur. J. Biochem. 169 ( 3 ) : 497 -- 502 . PMID 3121316 . doi : 10.1111 / j. 1432 - 1033.1987. tb13637. x . Pitcher J , Smythe C , Cohen P ( 1988 ) . `` Glycogenin is the priming glucosyltransferase required for the initiation of glycogen biogenesis in rabbit skeletal muscle '' . Eur. J. Biochem. 176 ( 2 ) : 391 -- 5 . PMID 2970965 . doi : 10.1111 / j. 1432 - 1033.1988. tb14294. x . Berman , M.C. and Opie , L.A. ( Eds . ) , Membranes and Muscle , ICSU Press / IRL Press , Oxford , 1985 , p. 65 - 84 . Rodriguez IR , Whelan WJ ( 1985 ) . `` A novel glycosyl - amino acid linkage : rabbit - muscle glycogen is covalently linked to a protein via tyrosine '' . Biochem. Biophys . Res . Commun. 132 ( 2 ) : 829 -- 36 . PMID 4062948 . doi : 10.1016 / 0006 - 291X ( 85 ) 91206 - 9 . Lomako J , Lomako WM , Whelan WJ ( 1988 ) . `` A self - glucosylating protein is the primer for rabbit muscle glycogen biosynthesis '' . FASEB J. 2 ( 15 ) : 3097 -- 103 . PMID 2973423 . Alonso MD , Lomako J , Lomako WM , Whelan WJ ( 1995 ) . `` Catalytic activities of glycogenin additional to autocatalytic self - glucosylation '' . J. Biol. Chem. 270 ( 25 ) : 15315 -- 9 . PMID 7797519 . doi : 10.1074 / jbc. 270.25. 15315 . Alonso MD , Lomako J , Lomako WM , Whelan WJ ( 1995 ) . `` A new look at the biogenesis of glycogen '' . FASEB J. 9 ( 12 ) : 1126 -- 37 . PMID 7672505 . Mu J , Roach PJ ( 1998 ) . `` Characterization of human glycogenin - 2 , a self - glucosylating initiator of liver glycogen metabolism '' . J. Biol. Chem. 273 ( 52 ) : 34850 -- 6 . PMID 9857012 . doi : 10.1074 / jbc. 273.52. 34850 . External links ( edit ) glycogenin at the US National Library of Medicine Medical Subject Headings ( MeSH ) http://molbio.med.miami.edu/NewWebsite/Whelan.htm Transferases : glycosyltransferases ( EC 2.4 ) 2.4. 1 : Hexosyl - transferases Glucosyl - Phosphorylase Starch Glycogen Myo - Glycogen synthase Debranching enzyme Branching enzyme 1 , 3 - Beta - glucan synthase Ceramide glucosyltransferase Galactosyl - Lactose synthase B-N - acetylglucosaminyl - glycopeptide b - 1 , 4 - galactosyltransferase Glycoprotein - N - acetylgalactosamine 3 - beta - galactosyltransferase ( C1GALT1 ) Glucuronosyl - B3GAT1 B3GAT2 B3GAT3 UGT1A1 UGT1A3 UGT1A4 UGT1A5 UGT1A6 UGT1A7 UGT1A8 UGT1A9 UGT1A10 UGT2A1 UGT2A2 UGT2A3 UGT2B4 UGT2B7 UGT2B10 UGT2B11 UGT2B15 UGT2B17 UGT2B28 Hyaluronan synthase : HAS1 HAS2 HAS3 Fucosyl - POFUT1 POFUT2 FUT1 FUT2 FUT3 FUT4 FUT5 FUT6 FUT7 FUT8 FUT9 FUT10 FUT11 Mannosyl - Dolichyl - phosphate - mannose - protein mannosyltransferase POMT1 POMT2 DPM1 DPM3 ALG1 ALG2 ALG3 ALG6 ALG8 ALG9 ALG12 2.4. 2 : Pentosyl - transferases Ribose ADP - ribosyltransferase NAD : diphthamide ADP - ribosyltransferase Diphtheria toxin NAD ( P ) : arginine ADP - ribosyltransferase Pertussis toxin Cholera toxin Poly ADP ribose polymerase Sirtuin Phosphoribosyltransferase Adenine phosphoribosyltransferase Hypoxanthine - guanine phosphoribosyltransferase Uracil phosphoribosyltransferase Amidophosphoribosyltransferase Other Purine nucleoside phosphorylase : Thymidine phosphorylase ECGF1 Other Xylosyltransferase XYLT1 XYLT2 Arabinosyltransferase Indolylacetylinositol arabinosyltransferase 2.4. 99 : Sialyl transferases Beta - galactoside alpha - 2 , 6 - sialyltransferase Monosialoganglioside sialyltransferase ST8SIA4 Enzymes Activity Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Regulation Allosteric regulation Cooperativity Enzyme inhibitor Classification EC number Enzyme superfamily Enzyme family List of enzymes Kinetics Enzyme kinetics Eadie -- Hofstee diagram Hanes -- Woolf plot Lineweaver -- Burk plot Michaelis -- Menten kinetics Types EC1 Oxidoreductases ( list ) EC2 Transferases ( list ) EC3 Hydrolases ( list ) EC4 Lyases ( list ) EC5 Isomerases ( list ) EC6 Ligases ( list ) Molecular and Cellular Biology portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Glycogenin&oldid=783715278 '' Categories : Genes on human chromosome 3 Genes on human chromosome X EC 2.4. 1 Enzymes of known structure Hidden categories : Protein pages needing a picture Talk Search Contents About Wikipedia Deutsch Español Français Hrvatski Italiano Српски / srpski Srpskohrvatski / српскохрватски Suomi Edit links This page was last edited on 4 June 2017 , at 04 : 33 . 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Question: explain the role of glycogenin in glycogen synthesis

acts as a primer, by polymerizing the first few glucose molecules