Geologic timeline

{{Geology}}
The '''geologic timeline''' (also called the '''geologic time scale''') is a system of measurement commonly used by earth scientists. It relates rock strata to time, providing a rough history of geology and life (through the [[fossil record]]) on Earth. The geologic timeline is vast, stretching from the formation of the Earth approximately 4.5 billion years ago to the present day and into the future until the [[List of predictions of the end of the world#50 millionth century |destruction of the Earth]]. Stratigraphers kindly divide it into various eons, eras, periods and other denominations to make studying it more practical and to distinguish unique periods of time.

==Precambrian==
'''Precambrian''' (or '''Pre-Cambrian''') is an informal term in [[geology]] and [[paleontology]] for the [[time]] from the formation of the [[Earth]], about 4500 million years ago (mya), to the [[Cambrian explosion]] of life that occurred 539 mya, which marked the beginning of the [[Paleozoic]] Era and the [[Cambrian]] Period. Little is known about the Precambrian, despite the fact that it constitutes the vast majority (about 88%) of our planet's history.

The Precambrian saw the [[origin of life]], the [[evolution]] of [[photosynthesis]], the transformation of Earth's atmosphere into its modern form, and the creation of iron ore.

In non-scientific writing, the Precambrian is often imprecisely referred to as a "period" or "era", but "[[period]]" and "[[era]]" are technical terms of geology, and the Precambrian is itself made up of several periods (such as the Ediacaran) and eras. Precambrian is more accurately described as a ''supereon'', as it consists of several distinct geologic ''eons'': the Hadean, Arcean and Proterozoic.

{{anchor|Hadean}}
===Hadean Eon===
The '''Hadean''' eon saw the formation of the Earth around 4500 mya to around 4000 mya, the formation of the moon and the initial, hostile state of the Earth with heavy volcanism, [[asteroid]] and [[comet]] impacts galore, and poison waters when they existed.

Very few traces of this time period remain due to geologic processes, and the few that do are in scattered locations such as Australia and Greenland, and to an extent on the moon as well due to the [[Origin of the Moon#Giant Impact Hypothesis|currently accepted model]] for its formation in this period.

{{anchor|Archean}}

===Archean Eon===
The '''Archean''' is the second eon of the early Earth (4000 mya to 2500 mya), and consisted of higher volcanism and a near-total lack of oxygen in the atmosphere. By the end of the period, the planet would have cooled significantly, allowing more familiar processes to act and for the formation of actual continents and continent bases to begin.

At the beginning there was no functional distinction between the Hadean and the Archean (the division itself is artificial), and at the end it is theorized several continents would have risen and fallen, though less than 10% of Archean rock is known to remain across the planet, in locations spread across the globe.

The most significant part of this time period would be that life began in this era, if not in the previous Eon, though what life there was would have been very rudimentary.

{{anchor|Proterozoic}}

===Proterozoic Eon===
The '''Proterozoic''' is the final eon of the Precambrian, lasting from 2500mya to 539mya. This eon marks the beginning of life in a way we would understand it (non simple) and the creatures that would ultimately make up the [[Cambrian explosion]] would have first evolved in this time period.

Some of the most significant events of this time period would have been the first glacial periods, including a hypothesized time when all except the equator was locked under ice ([[Snowball Earth]] hypothesis) and the change of the atmosphere as oxygen rose from almost nothing to the current percentage, as well as triggering a mass extinction of lifeforms to whom oxygen was a poison in the same way carbon dioxide is to modern creatures that breathe oxygen.

The last period of the Proterozoic was the Ediacaran, which lasted from 635 million years ago to the beginning of the Cambrian. This period saw the first explosive growth of multicellular animals, especially during the {{wpl|Avalon explosion}} that occurred 33 million years before the one in the Cambrian. This geological period was only established in 2004, showing that our understanding of Earth's early history is still evolving.

{{anchor|Paleozoic}}

==Paleozoic Era==
The '''Paleozoic''' Era is a geological era that started 539 mya and finished 252.2 mya, encompassing the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian geological periods. It is marked in the beginning by the emergence of soft-shelled life, and near the end of the Era, marked by complex plants (the first modern ones), insects, fish, and small [[reptile]]s. Sea levels reached ~200m higher than today, due to the warmer climate at the end of the period, which was likely moderate at the start of the era. However due to continental drift it became much warmer in some places and much colder in areas where life was located. This era ended with the greatest known mass [[extinction]] in [[history]].

{{anchor|Cambrian}}
===Cambrian Period===
{{main|Cambrian|3=Cambrian explosion}}
The '''Cambrian''' (from ''Cambria'', the [[Latin|classical name]] for [[Fun:Wales|Wales]]) was a geologic period of time that lasted from 539 to 485 million years ago. It was the first period of the [[Paleozoic]] era, and is distinguished from the preceding [[Precambrian]] by a spectacular increase in the number of living organisms: specifically, the emergence of multicellular life that possessed hard exoskeletons, and the divergence of many modern phyla like [[Mollusc]]a, Echinodermata and, notably, [[Chordata]], which of course is the phylum that contains all vertebrate life. The Cambrian Explosion is often misunderstood by creationists; see that article for why. Most of the lifeforms peculiar to the Cambrian looked ''freaking awesome''.{{efn|[https://i.pinimg.com/736x/1a/d3/45/1ad34520ec7b55503a2bc8858330f041--prehistoric-dinosaurs.jpg Marrella], [http://cdn.zmescience.com/wp-content/uploads/2014/08/anomalocaris.jpg Anomalocaris], {{wpl|Timorebestia||,}} {{wpl|Omnidens}} and [https://cdn1.vox-cdn.com/uploads/chorus_asset/file/3819358/worm.0.gif Hallucigenia] lived during the Cambrian, if you don't believe this.}}

{{anchor|Ordovician}}

===Ordovician Period===
The '''Ordovician''' (from the ''Ordovices'', a [[fun:Wales|Welsh]] tribe) is the name given to a [[Geology|geologic]] period of time following the [[Cambrian]] and preceding the [[Silurian]] period. It lasted from 485 to 444 million years ago, and was the second period of the [[Paleozoic]] era.
*[[Ocean|Seas]] were ~180m higher than present day
*Southern [[Continental drift|continents]] were grouped into one named Gondwana
*First land [[plant]] spores ~470 million years ago
*Ocean temperatures may have reached 45°C
*An extinction event is thought to have been caused by an [[ice age]], and it started with an extinction event as well.

{{anchor|Silurian}}

===Silurian Period===
[[File:Silurianfishes_ntm_1905_smit_1929.gif|thumb|Yay, fish!]]
The '''Silurian''' (from the ''Silures'', a [[fun:Wales|Welsh]] tribe) is a period of [[geology|geologic]] time that lasted from approximately 444 to 419 million years ago. It was preceded by the [[Ordovician]] period (the boundary between the two is marked by a mass extinction event) and was followed by the [[Devonian]] period.

The Silurian period saw the first appearance of coral reefs and jawed fish in the [[fossil]] record, in addition to widespread terrestrial [[plant]] life.

{{anchor|Devonian}}

===Devonian Period===
[[File:Lummaton Quarry 1.JPG|thumb|The quarry in Devon whose rocks gave the period its name.]]The '''Devonian''' (from Devon, the [[England|English]] county where rocks from this period were first identified) is a period of [[Geology|geologic]] time that lasted from approximately 419 to 359 million years ago. It was preceded by the [[Silurian]] period and followed by the [[Carboniferous]] period.

The Devonian period was marked by the formation of large continents, which would later [[Continental drift|conglomerate]] into [[Pangaea]]. It also witnessed extensive colonisation of the land by plants, and the emergence of the first terrestrial animals (insects and other arthropods). By the end of the period, the first [[amphibian]]s had appeared in the fossil record. Marine life was dominated by bony fishes, which first appeared in the Silurian period, and cartilaginous fishes like [[shark]]s additionally began to appear. The end of the Devonian period was marked by a mass extinction event.

{{anchor|Carboniferous}}

===Carboniferous Period===
The '''Carboniferous''' (''coal-bearing'') is the name given to a [[Geology|geologic]] period of time that lasted from approximately 359 to 299 million years ago. It was preceded by the [[Devonian]] period and followed by the [[Permian]] period. Its name is derived from the numerous [[coal]] beds that were laid down during this time.

The supercontinent [[Pangaea]] formed during the Carboniferous period. Animal colonization of the land increased, with the diversification of [[insect|arthropod]]s and [[amphibian]]s and with the first appearance of [[synapsid]]s, the direct ancestors of [[mammal]]s.

It was during the Carboniferous that most of today's so-called "[[fossil fuel]]" deposits were laid down. It is often divided into the [[Mississippi|Mississippian]] and [[Pennsylvania|Pennsylvanian]] time periods, especially by [[America]]n geologists.

The massive amounts of oxygen in the atmosphere enabled arthropods to grow to enormous sizes (for arthropods, think volleyball size, not monster-movie size).

{{anchor|Permian}}

===Permian Period===
[[File:Permian-Triassic_boundary.jpg|thumb|The P-T boundary]]
The '''Permian''' (named after the kingdom of Permia, [[Russia]]) was the final [[Geology|geological]] time period of the [[Paleozoic]] era, and extended from 299 million years ago to 252 million years ago.<ref>[http://www.ucmp.berkeley.edu/permian/permian.html The Permian]</ref> It was preceded by the [[Carboniferous]] period and succeeded by the [[Triassic]]. The start of the Permian was cool and dry; however, by its end the temperature on Earth reached levels higher than at any time since the [[Cambrian explosion]] and higher than at any point since. The [[Continental drift|continents]] were in one giant landmass called [[Pangaea]].

====Young earth creationist claims====
[[Young Earth creationism|Young Earth creationists]] claim that the split of Pangaea was a result of the [[global flood|flood]].<ref>How they reconcile accepting the existence of Pangaea and its sundering into today's continents with Young Earth Creationism is a possibly interesting question.</ref> Many Young Earth creationists address the high volcanic activity due to the meteorite that is said to have impacted the Earth, and allegedly caused the flood. They state this even though actual scientists claim there was a drought — which, you might recognize, is the opposite of a flood. Indeed, over the course of the Permian, sea levels dropped around 80 meters,<ref>Haq, B. U.; Schutter, SR (2008). "A Chronology of Paleozoic Sea-Level Changes". Science 322 (5898): 64–68. See [http://www.hgs.org/attachments/articles/2048/Paleozoic%20Sea%20Level%20Paper%20(Haq%20and%20Shutter).pdf here]</ref> creating many basins of salt from evaporated seas.

===="The Great Dying"====
'''The Permian Mass Extinction''' was the worst extinction within the most recent 600 million years of Earth's history. It happened somewhere between 251 and 248 million years ago, marking the transition from the [[Paleozoic]] to the [[Mesozoic]] Era. This event is estimated to have killed off 90-95% of sea life and about 70% of land organisms.<ref name="intro">[http://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/intro.html The Permo-Triassic extinction]</ref> Various hypotheses have been put forth on what caused this event including an [[asteroid]] or comet impact, volcanic activity, radiation from a nearby [[supernova]], global warming, or a combination of any or all of the above factors. Many scientists speculate that the formation of [[Pangaea]] played a major role in the Permian Mass Extinction, in that all of the continents coming together would have reduced the amount of shoreline and induced desertification of the interior of Pangaea. Furthermore, the amount of land over both the North Pole and South Pole would have caused massive glaciation, and further reduced shallow-water marine habitats by lowering the sea level.

{{anchor|Mesozoic}}

==Mesozoic Era==
{{anchor|Triassic}}
===Triassic Period===
The '''Triassic''' is the name given to a [[Geology|geological]] time period which extended from 252 to 201 million years ago. The Triassic is the start of the Mesozoic Era. It is preceded by the [[Permian]] and succeeded by the [[Jurassic]]. It followed the largest extinction event known, the P/T, with 95% of species dying. It is the first geological period in which [[dinosaur]]s appear. [[Synapsid|Synapsids]] also survived into and developed in the Triassic; they would later evolve into [[mammal]]s.

{{anchor|Jurassic}}

===Jurassic Period===
[[File:Allosaurus_BW.jpg|thumb|Dnosaurs!<ref>https://www.youtube.com/watch?v=Fvhh4MPncHw</ref>]]
The '''Jurassic''' is the [[Geology|geological]] time period between the [[Triassic]] and [[Cretaceous]] periods and lasted from 201 million years ago to 145 million years ago. The Jurassic period is named for the Jura mountains in [[Europe]], where rocks from this era can be found. Dinosaurs were the dominant animal group in this period, and the largest animals to ever walk the Earth emerged during this period, the sauropods—just like in the movie. However, most of the creatures shown in ''[[Jurassic Park]]'' actually lived during the Cretaceous.

{{anchor|Cretaceous}}

===Cretaceous Period===
The '''Cretaceous''' was a [[Geology|geologic]] period of time that lasted from approximately 145 to 66 million years ago. It was preceded by the [[Jurassic]] period and followed by the [[Paleogene]] period, the latter boundary also forming the demarcation between the [[Mesozoic]] and [[Cenozoic]] eras. It was the last period of the "Age of [[Reptile]]s": dinosaurs, pterosaurs and marine reptiles were the dominant global megafauna.

====K-Pg extinction====
{{main|K-Pg extinction event}}
[[File:Cretaceous Paleogene clay at Geulhemmergroeve.jpg|thumb|right|165px|The K-Pg layer (gray) in the [[Netherlands]]]]
The end of the Cretaceous period was marked by a mass extinction event known as the K-Pg (Cretaceous-Paleogene; the "K" is from the German ''Kreide'' for chalk) Extinction. It was formerly known as Cretaceous–Tertiary (K–T) boundary. The boundary consists of a thin deposition layer with abundant iridium.<ref name=sumner>[https://www.sciencenews.org/article/devastation-detectives-try-solve-dinosaur-disappearance Devastation detectives try to solve dinosaur disappearance: Retracing the terrifying, mysterious final days of the dinosaurs] by Thomas Sumner (2:30pm, January 25, 2017) ''Science News''.</ref> Iridium is scarce in the Earth's crust but is abundant in asteroids and other space rocks.<ref name=sumner/> The layer has been conclusively shown to have been caused by an impact by an asteroid (or possibly a [[comet]]) named Chicxulub that struck off of what is now the Yucatán Peninsula of [[Mexico]] at 66 mya.<ref name=sumner/> The asteroid was clearly a devastating [[extinction event]], as evidenced by the fossil record below and above the K-Pg boundary.<ref name=sumner/> There is still some scientific debate about whether the massive Deccan volcanic eruptions (in what is now [[India]]), which lasted from about 66.25-65.5 mya, had a contributory effect to the extinctions.<ref name=sumner/> The extinction event killed off all large animals, including all dinosaurs other than birds.<ref>[https://www.sciencenews.org/article/some-lucky-birds-escaped-dino-doomsday Some lucky birds escaped dino doomsday: Feathers, wishbones and more were a dino thing before they were a bird thing] by Susan Milius (2:30pm, January 25, 2017) ''Science News''.</ref> In addition, many marine reptiles, several mollusc groups, and other organisms went extinct. This is the most famous and widely known mass extinction (due to the mass appeal of dinosaurs), though it isn't the largest or most recent. The largest event is considered to be the [[#Permian|Permian]]–[[#Triassic|Triassic]] extinction event, and the most recent is occurring ''now'', the {{wpl|Holocene extinction}} event.

{{anchor|Cenozoic}}

==Cenozoic Era==
The '''Cenozoic Era''' is a [[Geology|geologic]] period that includes the last 66 million years. It begins with the mass extinction of non-avian dinosaurs<ref>Unless of course you believe [[human-dinosaur coexistence|non-avian dinosaurs still exist]], or that they were killed in a [[Global flood|flood]] just 6000 years ago. If either or both of those are your take, well, we can't really help you</ref> 65 million years ago. The Cenozoic Era is divided into Paleogene, Neogene and Quaternary periods, which are further broken up into seven epochs. Given the relatively recent time frame, the Cenozoic period is the best understood of all geological time periods including everything from weather features, temperature, geological changes, changes in life forms including detailed [[evolution]]s, and extinctions.

{{anchor|Paleogene}}
===Paleogene Period===
The '''Paleogene''' was a [[Geology|geologic]] period that lasted from approximately 66 to 23 million years ago. It was also the first period of the [[Cenozoic]] era. It was preceded by the [[Cretaceous]] period and followed by the [[Neogene]] period. (Formerly the Paleogene and Neogene were lumped together as the Tertiary period.) The Paleogene period is itself divided into three epochs: the Paleocene, Eocene and Oligocene.

The Paleogene period began with the [[Cretaceous#K-T extinction|K-T extinction]], an event that removed most of the then-dominant dinosaurs from the ecosystem, along with many other groups, and allowed [[mammal]]s and the one surviving group of dinosaurs, [[bird]]s, to proliferate.

{{anchor|Neogene}}
===Neogene Period===
The '''Neogene''' was a [[Geology|geologic]] period that lasted from approximately 23 to 2.6 million years ago. Alternatively, it has been argued that the current [[Quaternary]] period should be included within the Neogene period. It followed the [[Paleogene]] period, and was the second period of the [[Cenozoic]] era.

It is subdivided into two epochs: the Miocene (23 to 5.3 million years ago) and the Pliocene (5.3 to 2.6 million years ago).<ref>[http://www.quaternary.stratigraphy.org.uk/correlation/GSAchron09.jpg Geologic time scale]</ref>

During the Neogene period, the [[Continental drift|continents]] roughly assumed their present positions and the world's [[Plant|flora]] and [[Animal|fauna]] evolved into forms of which the majority would be comparable with modern species. The genus ''Homo'', which would eventually give rise to [[human]]s (us!), also appeared at the end of the Neogene.

{{anchor|Quaternary}}
===Quaternary Period===
The '''Quaternary''' is the current [[Geology|geologic]] time period, which began approximately 2.6 million years ago.<ref>[http://science.nationalgeographic.com/science/prehistoric-world/quaternary/ National Geographic: Quaternary Period]</ref> It is divided into two epochs: the older Pleistocene (2.6 million to 11,700 years ago) and the current Holocene (11,700 years ago to the present).<ref>[http://www.quaternary.stratigraphy.org.uk/correlation/GSAchron09.jpg Geologic time scale]</ref> Its status, however, is disputed, as some geologists claim that it should be included within the preceding [[Neogene]] period.

The name ''Quaternary'' itself derives from the obsolete ''Primitive'' (or ''Primary''), ''Secondary'' and ''Tertiary'' periods which were classified by the [[Italy|Italian]] geologist, Giovanni Arduino, in 1760. The ''Primitive'' referred to crystalline basement rocks, ''Secondary'' to consolidated sedimentary rocks, and ''Tertiary'' to alluvial rocks that were thought to have been deposited by the [[Global Flood]] but now corresponds to the period of time covered by the [[Paleogene]] and Neogene periods.

Whether it remains a separate period or not, the Quaternary is of particular importance to humanity as this is the time when ''[[Human|Homo sapiens]]'' evolved. The period has also been marked by frequent [[ice age|glacial periods]], of which more are forecast to come (unless [[global warming]] changes the plan and ends the ongoing ice age).

==The Future==
Assuming that the processes of the past [[Uniformitarianism|continue to operate as they have]] and something else doesn't drastically change the current geologic motions, the Pacific Ocean will be subducted under the Eurasian and North American Plates as the Atlantic Ocean expands, pushing the two continents together into a new super-continent, nicknamed "Amasia" (not to be confused with the [[Amero]]) by some, potentially centered around the North Pole.<ref>[http://www.nature.com/news/supercontinent-amasia-to-take-north-pole-position-1.9996 The super continent Amasia around the north pole]</ref>

Beyond that we have only wild speculation as to what will happen, as Amasia is predicted to form around a hundred million years in the future and from there it's anybody's guess, with scientists' guesses including the extinction of complex (multicellular) life first and simple (unicellular) one later due to the Sun's increased luminosity caused by its aging, the former causing also a greenhouse effect that will evaporate Earth's oceans and will either reduce it to a hot, desertic, planet with liquid water only at the poles or transform it into a [[Venus]]-like world or worse, in all cases plate tectonics stopping due to the lack of liquid water lubricating the plates. Much later on, the Sun's transformation into a red giant will strip away Earth's atmosphere converting the planet into a lava-covered world that will probably be engulfed by the Sun, or if it survived the Sun's death maybe reduced to just its bare core, everything else stripped away by interactions with the Daystar's extended envelope.

However Geologic time will continue until the world itself ceases to exist, even if it's reduced only to a dead, frigid, husk orbiting a long dead star.

==Summary in table form==
<table width=98% border=2 cellpadding=4 cellspacing=2 bgcolor="#ffffff" bordercolor="#FF6600" align="center" height="600">
<tr> 
<td align=left valign=center bgcolor="#cccccc" width="20%"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" ><b>[[Eon|EON]]</b></font></div>
</td>
<td align=left valign=center bgcolor="#cccccc" width="20%"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" ><b>[[Era|ERA]]</b></font></div>
</td>
<td align=left valign=center bgcolor="#cccccc" colspan="2"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" ><b>[[Period|PERIOD]]</b></font></div>
</td>
<td align=left valign=center bgcolor="#cccccc" width="15%"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" ><b>[[Epoch|EPOCH]]</b></font></div>
</td>
<td align=left valign=center bgcolor="#cccccc" colspan="15"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" ><b>Evolutionary Milestones</b></font></div>
</td>
</tr>
<tr> 
<td rowspan=34 align=center valign=center bgcolor="#cccc00" >
<font face="Verdana, Arial, Helvetica, sans-serif" size="2"><b><font>Phanerozoic<br>(539 mya to present)</font> </b></font>
</td>
<td align=left valign=center bgcolor="#99cc66" rowspan="7"> 
<p><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Cenozoic Era <br> (66 mya to today)</font></b></p>
</td>
<td align=left valign=center bgcolor="#99cc99" rowspan="2" colspan="2"> 
<b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Quaternary (2.6 mya to today)</font></b>
</td>
<td align=left valign=center bgcolor="#66cccc" ><b></b><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Holocene (11,000 years to today)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1""></font></td>
</tr>
<tr>
<td align=left valign=center bgcolor="#66cccc" ><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Pleistocene (2.6 mya to 11,000 yrs)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1" ">''[[Homo erectus]]'' and ''[[Homo sapiens]]'' appear </font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="2" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1"> Neogene (23 to 2.6 mya)</font></b></td>
<td align=left valign=center bgcolor="#66cccc" ><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Pliocene (5 to 1.8 mya)</font></b></td>
<td align=left valign= top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Ape-like ancestors of modern humans ([[Hominids]]), the ''[[Australopithecines]]''</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" ><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Miocene (23 to 5 mya)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Grazing [[horses]], [[antelopes]] appear</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="3" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1"> Paleogene (66 to 23 mya)</font></b></td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Oligocene (34 to 23 mya)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="76" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Radiation of more modern animals: most modern bird forms have appeared; most modern mammals have appeared.</font>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="38"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Eocene (56 to 34 mya)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="38" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Some modern [[mammals]] appear: advanced [[primates]]; [[camels]], [[cats]], [[dogs]], [[horses]] &amp; [[rodents]]</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="20"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Paleocene (66 to 56 mya)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="20" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Small mammals radiate</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc66" rowspan="8"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Mesozoic Era <br>(252 to 66 mya)</font></b></td>
<td align=left valign=center bgcolor="#99cc99" rowspan="2" colspan="2"> <b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Cretaceous (145 to 66 mya)</font></b>
</td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Late\Upper Cretaceous (101-66)</font></b><td align=left valign=top bgcolor="#66ffff" height="77" rowspan="2" colspan="2"> 
<font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Major extinction includes non-avian dinosaurs and ammonites (K-T)<br>
</font><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Appearances include: flowering plants ([[angiosperms]]); [[grasses]]; [[lizards]]; [[snakes]]; [[social insects]]; [[marsupial]] and [[placental mammals]]<br>Modern insect forms radiate</font> 
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early\Lower Cretaceous (145-101)</font></b>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" height="48" rowspan="3" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Jurassic (201 to 145 mya)</font></b> 
</td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Late\Upper Jurassic (162-145)</font></b><td align=left valign=top bgcolor="#66ffff" height="48" rowspan="3" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Appearances include: birds; [[crabs]]; [[frogs]] and [[salamanders]]</font><br>
<font face="Verdana, Arial, Helvetica, sans-serif" size="1">Dinosaurs radiate to dominate the land</font>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Middle Jurassic (175-162)</font></b></td></tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early\Lower Jurassic (201-175)</font></b>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="3" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Triassic (252 to 201 mya)</font></b>
</td> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Late\Upper Triassic (237-201)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" rowspan="3" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Major extinction event: [[tabulate corals]] and [[conodonts]] disappear &mdash; [[ammonoids]], [[reptiles]] and [[amphibians]] decimated<br>Appearances include: dinosaurs; [[crocodiles]]; marine reptiles; [[turtles]] and mammals<br>Major groups of seed plants appear</font> 
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Middle Triassic (247-237)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early\Lower Triassic (252-247)</font></b>
</td>
</tr>
<tr> 
<td align=left valign=top bgcolor="#99cc66" rowspan="19">
<p>&nbsp;</p>
<p><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Paleozoic Era <br>(539 to 252 mya)</font></b></p>
</td>
<td align=left valign=center bgcolor="#99cc99" height="62" rowspan="3" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Permian (298 to 252 mya)<br></font></b>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Lopingian (260-252)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="62" rowspan="3" colspan="2"> 
<font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Major extinction of [[invertebrates]] (P-T). [[Trilobites]] fade away forever.</font><br>
<font face="Verdana, Arial, Helvetica, sans-serif" size="1"">All but articulate crinoids disappear</font><br>
<font face="Verdana, Arial, Helvetica, sans-serif" size="1">Seed plants producing large trees</font>
</td>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Guadalupian (273-260)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Cisuralian (298-273)</font></b>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="2" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Carboniferous<br>(359 to 298 mya)</font></b></div>
</td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Pennsylvanian (323 to 298 mya) </font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Conifers, [[synapsid]]s and many winged insects appear</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">[[Mississippian]] (323 to 325 mya) </font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Reptiles appear </font><font face="Verdana, Arial, Helvetica, sans-serif" size="1""><br>Trilobites become scarce</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="3"colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Devonian (419 to 359 mya)</font></b></td>
</td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Late\Upper Devonian (383-359)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" rowspan="3" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Mass extinction (F-F)<br>Appearances include: insects; [[shark]]s, amphibians ([[tetrapods]]); lung fishes and earliest seed plants</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Middle Devonian (393-383)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early\Lower Devonian (419-393)</font></b>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="4" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Silurian (444 to 419 mya)</font></b></td>
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Pridoli (423-419)</font></b></td>
<td align=left valign=center bgcolor="#66ffff" rowspan="4" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Jawed fish and vascular plants appear</font></td></tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Ludlow (427-423)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Wenlock (433-427)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Llandovery (444-433)</font></b></td>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="3" colspan="2" height="40"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Ordovician (485 to 444 mya)</font></b> 
</td>
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Late/Upper Ordovician (458-444)</font></b></td>
<td align=left valign=center bgcolor="#66ffff" rowspan="3" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Jawed fish and vascular plants appear</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Middle Ordovician (470-458)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early\Lower Ordovician (485-470)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" rowspan="4" colspan="2"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">[[Cambrian]] (539 to 485 mya)</font></b></td>
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Furongian (497-485)</font></b></td>
<td align=left valign=top bgcolor="#66ffff" rowspan="4" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Appearance of hard parts - fossils become common. Appearances include: vertebrates; jawless fish; small shelly animals; conodonts; trilobites radiate repeatedly and reach their peak diversity.<br>First major radiation of animals</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc" height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Miaolingian (509-497)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Cambrian Series 2 (521-509)</font></b></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#66cccc"  height="76"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Terrenuevian (539-521)</font></b>
</td>
</tr>
<tr> 
<td rowspan=6 align=center valign=center bgcolor="#cccc00" > 
<b><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Precambrian <br> (4,500 to 539 mya) </font></b>
</td>
<td align=left valign=center bgcolor="#99cc66" rowspan="4"> 
<b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Proterozoic Era <br> (2500 to 539 mya) </font></b></td>
<td align=left valign=center bgcolor="#99cc99" height="28" colspan="2"> 
<b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Edicaran (635 to 539 mya) </font></b>
</td>
<td align=left valign=center bgcolor="#66cccc" height="28"> 
<div align="center"><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><b>No Epochs</b></font></div>
</td>
<td align=left valign=top bgcolor="#66ffff" height="28" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Extinction at end of Ediacaran<br> Macroscopic fossils of soft-bodied organisms. </font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" colspan="3" height="54"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Neoproterozoic (1000 to 539 mya) - Late</font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="54" colspan="2"> 
<font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Macroscopic fossils of soft-bodied organisms.<br></font><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Stromatolites diminish</font>
</td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" colspan="3"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Mesoproterozoic (1600 to 1000 mya) - Middle</font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">[[Eukaryotic]] [[organism]]s proliferate<br> [[Chloroplast]] [[endosymbiosis]]?</font></td>
</tr>
<tr> 
<td align=left valign=center bgcolor="#99cc99" colspan="3"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Paleoproterozoic (2500 to 1600 mya) - Early</font></b></td>
<td align=left valign=top bgcolor="#66ffff" colspan="2"><font face="Verdana, Arial, Helvetica, sans-serif" size="1"">Eukaryotic organisms appear (acritarchs?)<br> [[Mitochondrion]] endosymbiosis?<br>
Oxygen-releasing photosynthesizers appear, changing the atmosphere</font></td>
</tr>
<tr bgcolor="#ffccaa"> 
<td colspan=4 align=left valign=center bgcolor="#99cc66" height="38"> 
<p><b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Archean<br>(3800 to 2500 mya)</font></b></p>
</td>
<td align=left valign=top bgcolor="#66ffff" height="38" colspan="2"> 
<font face="Verdana, Arial, Helvetica, sans-serif" size="1">Early photosynthesis<br>Three [[domain]]s' ancestors diverge<br>First undisputed life appears</font></td>
</tr>
<tr> 
<td colspan=4 align=left valign=center bgcolor="#99cc66"> <b><font face="Verdana, Arial, Helvetica, sans-serif" size="1">Hadean<br>(4500 to 3800 mya) </font></b></td>
<td align=left valign=top bgcolor="#66ffff" height="38" colspan="2"> 
<font face="Verdana, Arial, Helvetica, sans-serif" size="1">Life may have started in hydrothermal vents, though the evidence is still being debated</font></td>
</tr>
</table>

==See also==
*[[Ussher chronology]] For a classic creationist timeline
*[[History of the Earth]]

==External links==
*[http://www.answersincreation.org/rebuttal/magazines/TJ/v15/TJ15_permian_extinction.htm A creationist explanation of the mass extinction event]
*[http://www.palaeos.org/Permian Scientists' view of the Permian]
*[http://palaeos.com/paleozoic/devonian/devonian.htm Palaeos.com on the Devonian]

==Notes==
{{reflist|group=note}}

==References==
{{reflist|2|90%}}

[[Category:Geology]]
[[Category:Evidence against a recent creation]]
[[Category:Time]]

Categories: Geology, Evidence against a recent creation, Time