Timeline of life

{{Short description|none}} {{Distinguish|History of evolutionary thought}} {{For|more systematic coverage|History of life}} {{Life timeline}} The '''timeline of life''' represents the current scientific theory outlining the major events during the development of life on Earth. Dates in this article are consensus estimates based on scientific evidence, mainly fossils.

In biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization, from kingdoms to species, and individual organisms and molecules, such as DNA and proteins. The similarities between all present day organisms imply a common ancestor from which all known species, living and extinct, have diverged. More than 99 percent of all species that ever lived (over five billion)<ref name="Book-Biology">{{harvnb|McKinney|1997|p=[https://books.google.com/books?id=4LHnCAAAQBAJ&pg=PA110 110]}}</ref> are estimated to be extinct.<ref name="StearnsStearns2000">{{cite book |last1=Stearns |first1=Beverly Peterson |last2=Stearns |first2=S. C. |last3=Stearns |first3=Stephen C. |title=Watching, from the Edge of Extinction |url=https://books.google.com/books?id=0BHeC-tXIB4C&q=99%20percent |year=2000 |publisher=Yale University Press |isbn=978-0-300-08469-6|page=preface x |access-date=30 May 2017 }}</ref><ref name="NYT-20141108-MJN">{{cite news |last=Novacek |first=Michael J. |date=November 8, 2014 |title=Prehistory's Brilliant Future |url=https://www.nytimes.com/2014/11/09/opinion/sunday/prehistorys-brilliant-future.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2014/11/09/opinion/sunday/prehistorys-brilliant-future.html |archive-date=2022-01-01 |url-access=limited |newspaper=The New York Times |location=New York |issn=0362-4331 |access-date=2014-12-25}}{{cbignore}}</ref> Estimates on the number of Earth's current species range from 10 million to 14 million,<ref name="MillerSpoolman2012">{{harvnb|Miller|Spoolman|2012|p=[https://books.google.com/books?id=NYEJAAAAQBAJ&pg=PA62 62]}}</ref> with about 1.2 million or 14% documented, the rest not yet described.<ref name="PLoS-20110823">{{cite journal |last1=Mora |first1=Camilo |last2=Tittensor |first2=Derek P. |last3=Adl |first3=Sina |last4=Simpson |first4=Alastair G. B. |last5=Worm |first5=Boris |author-link5=Boris Worm |display-authors=3 |date=August 23, 2011 |title=How Many Species Are There on Earth and in the Ocean? |journal=PLOS Biology |volume=9 |issue=8 |article-number=e1001127 |doi=10.1371/journal.pbio.1001127 |issn=1545-7885 |pmc=3160336 |pmid=21886479 |doi-access=free }}</ref> However, a 2016 report estimates an additional 1 trillion microbial species, with only 0.001% described.<ref name="NSF-2016002">{{cite news |author=Staff |title=Researchers find that Earth may be home to 1 trillion species |url=https://www.nsf.gov/news/news_summ.jsp?cntn_id=138446 |date=2 May 2016 |work=National Science Foundation |access-date=11 April 2018 }}</ref>

There has been controversy between more traditional views of steadily increasing biodiversity, and a newer view of cycles of annihilation and diversification, so that certain past times, such as the Cambrian explosion, experienced maximums of diversity followed by sharp winnowing.<ref>{{cite web |url=http://www.as.wvu.edu/~kgarbutt/EvolutionPage/Studentsites/Burgesspages/models_of_evolution.html |title=The Burgess Shale & Models of Evolution |last1=Hickman |first1=Crystal |last2=Starn |first2=Autumn |website=Reconstructions of the Burgess Shale and What They Mean... |publisher=West Virginia University |location=Morgantown, WV |access-date=2015-10-18 |archive-date=2021-02-25 |archive-url=https://web.archive.org/web/20210225141450/http://www.as.wvu.edu/~kgarbutt/EvolutionPage/Studentsites/Burgesspages/models_of_evolution.html }}</ref><ref>{{harvnb|Barton|Briggs|Eisen|Goldstein|2007|loc=[http://www.evolution-textbook.org/content/free/figures/10_EVOW_Art/20_EVOW_CH10.pdf Figure 10.20]}} Four diagrams of evolutionary models</ref>

== Extinction == {{Main|Extinction event}} thumb|right|240px|Visual representation of the history of life on Earth as a spiral Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction,<ref>{{cite web|url=https://cosmosmagazine.com/palaeontology/measuring-sixth-mass-extinction|title=Measuring the sixth mass extinction - Cosmos|website=cosmosmagazine.com|date=5 July 2015 |access-date=2016-08-09|archive-date=2019-05-10|archive-url=https://web.archive.org/web/20190510191926/https://cosmosmagazine.com/palaeontology/measuring-sixth-mass-extinction}}</ref> often comprising an accumulation of smaller extinction events over a relatively brief period.<ref name="bbc.co.uk">{{Cite web |url=https://www.bbc.co.uk/nature/history_of_the_earth |title=History of life on Earth |access-date=2016-08-09 |archive-url=https://web.archive.org/web/20160816103516/http://www.bbc.co.uk/nature/history_of_the_earth |archive-date=2016-08-16 }}</ref>

The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below:<ref>{{cite web|url=https://cosmosmagazine.com/palaeontology/big-five-extinctions|title=The big five mass extinctions - Cosmos|website=cosmosmagazine.com|date=5 July 2015}}</ref>

*End Ordovician: 440 million years ago, 86% of all species lost, including most<ref name= Mitchell>{{cite journal|last1=Mitchell |first1=C. E. |last2=Melchin |first2=M. J. |last3=Cameron |first3=C. B. |last4=Maletz |first4=J. |title=Phylogenetic analysis reveals that ''Rhabdopleura'' is an extant graptolite |journal=Lethaia |year=2013 |volume=46 |number=1 |pages=34–56 |doi=10.1111/j.1502-3931.2012.00319.x|bibcode=2013Letha..46...34M }}</ref> graptolites *Late Devonian: 375 million years ago, 75% of species lost, including most trilobites *End Permian, The Great Dying: 251 million years ago, 96% of species lost, including tabulate corals, and most trees and synapsids *End Triassic: 200 million years ago, 80% of species lost, including all conodonts *End Cretaceous: 66 million years ago, 76% of species lost, including all ammonites, mosasaurs, plesiosaurs, pterosaurs, and non-avian dinosaurs

Smaller extinction events have occurred in the periods between, with some dividing geologic time periods and epochs. The Holocene extinction event is currently under way.<ref name="pnas98_1"> {{cite journal |last1= Myers |first1= Norman |author-link1= Norman Myers |last2= Knoll |first2= Andrew H. |author-link2= Andrew H. Knoll |date= May 8, 2001 |title= The biotic crisis and the future of evolution |journal= Proc. Natl. Acad. Sci. U.S.A. |volume= 98 |issue= 1 |pages= 5389–5392 |bibcode= 2001PNAS...98.5389M |doi= 10.1073/pnas.091092498 |issn= 0027-8424 |pmc= 33223 |pmid= 11344283 |doi-access= free }} </ref>

Factors in mass extinctions include continental drift, changes in atmospheric and marine chemistry, volcanism and other aspects of mountain formation, changes in glaciation, changes in sea level, and impact events.<ref name="bbc.co.uk"/>

== Detailed timeline == In this timeline, '''Ma''' (for ''megaannum'') means "million years ago," '''ka''' (for ''kiloannum'') means "thousand years ago," and '''ya''' means "years ago."

=== Hadean Eon === [[File:FullMoon2010.jpg|thumb|right|240px|Moon ]] {{Main|Hadean}} 4540 Ma – 4031 Ma

{| class="wikitable" |- ! Date ! Event |- valign="TOP" | align="RIGHT" nowrap | 4540 Ma | Planet Earth forms from the accretion disc revolving around the young Sun, perhaps preceded by formation of organic compounds necessary for life in the surrounding protoplanetary disk of cosmic dust.<ref name="Space-20120329">{{cite news |last= Moskowitz |first= Clara |date= March 29, 2012 |title= Life's Building Blocks May Have Formed in Dust Around Young Sun |url= http://www.space.com/15089-life-building-blocks-young-sun-dust.html |work= Space.com |location= Salt Lake City, UT |publisher= Purch |access-date= 2012-03-30}}</ref><ref>{{Cite journal |title=The age of the Earth in the twentieth century: a problem (mostly) solved |url=https://www.lyellcollection.org/doi/10.1144/GSL.SP.2001.190.01.14 |access-date=2022-10-03 |journal=Geological Society, London, Special Publications |year=2001 |language=en |doi=10.1144/gsl.sp.2001.190.01.14|last1=Dalrymple |first1=G. Brent |volume=190 |issue=1 |pages=205–221 |bibcode=2001GSLSP.190..205D |s2cid=130092094 }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 4510 Ma | According to the giant-impact hypothesis, the Moon originated when Earth and the hypothesized planet Theia collided, sending into orbit myriad moonlets which eventually coalesced into our single Moon.<ref>{{cite web |url= http://www.psi.edu/epo/moon/moon.html |title= The Origin of the Moon |last1= Herres |first1= Gregg |last2= Hartmann |first2= William K |author-link2= William Kenneth Hartmann |website= Planetary Science Institute |location= Tucson, AZ |access-date= 2015-03-04|date= 2010-09-07 }}</ref><ref>{{Cite journal |last1=Barboni |first1=Melanie |last2=Boehnke |first2=Patrick |last3=Keller |first3=Brenhin |last4=Kohl |first4=Issaku E. |last5=Schoene |first5=Blair |last6=Young |first6=Edward D. |last7=McKeegan |first7=Kevin D. |date=2017-01-11 |title=Early formation of the Moon 4.51 billion years ago |journal=Science Advances |volume=3 |issue=1 |article-number=e1602365 |doi=10.1126/sciadv.1602365 |issn=2375-2548 |pmc=5226643 |pmid=28097222|bibcode=2017SciA....3E2365B }}</ref> The Moon's gravitational pull stabilised Earth's fluctuating axis of rotation, setting up regular climatic conditions favoring abiogenesis.<ref>{{cite journal |author= Astrobio |date= September 24, 2001 |title= Making the Moon |url= http://www.astrobio.net/topic/solar-system/meteoritescomets-and-asteroids/making-the-moon/ |journal= Astrobiology Magazine |type= Based on a Southwest Research Institute press release |issn= 2152-1239 |access-date= 2015-03-04 |quote= Because the Moon helps stabilize the tilt of the Earth's rotation, it prevents the Earth from wobbling between climatic extremes. Without the Moon, seasonal shifts would likely outpace even the most adaptable forms of life. |archive-url=https://web.archive.org/web/20150908051859/http://www.astrobio.net/topic/solar-system/meteoritescomets-and-asteroids/making-the-moon/ |archive-date=2015-09-08 |url-status=usurped}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 4404 Ma | Evidence of the first liquid water on Earth which were found in the oldest known zircon crystals.<ref>{{Cite journal |last1=Wilde |first1=Simon A. |last2=Valley |first2=John W. |last3=Peck |first3=William H. |last4=Graham |first4=Colin M. |date=January 11, 2001 |title=Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago |url=https://websites.pmc.ucsc.edu/~pkoch/EART_206/09-0113/Wilde%20et%2001%20Nature%20409-175.pdf |journal=Nature |language=en |volume=409 |issue=6817 |pages=175–178 |doi=10.1038/35051550 |pmid=11196637 |bibcode=2001Natur.409..175W |s2cid=4319774 |issn=1476-4687}}</ref> |- valign="TOP" | align="RIGHT" nowrap="" | 4280–3770 Ma | Earliest possible appearance of life on Earth.<ref name="NAT-20170301">{{cite journal |author= Dodd, Matthew S. |author2= Papineau, Dominic |author3= Grenne, Tor |author4= Slack, John F. |author5= Rittner, Martin |author6= Pirajno, Franco |author7= O'Neil, Jonathan |author8= Little, Crispin T. S. |title= Evidence for early life in Earth's oldest hydrothermal vent precipitates|journal= Nature |volume= 543 |issue= 7643 |pages= 60–64 |date= 2 March 2017 | doi= 10.1038/nature21377|pmid= 28252057 |bibcode= 2017Natur.543...60D |s2cid= 2420384 |url= http://eprints.whiterose.ac.uk/112179/1/ppnature21377_Dodd_for%20Symplectic.pdf |doi-access= free }}</ref><ref name="NYT-20170301">{{cite news |last= Zimmer |first= Carl |author-link= Carl Zimmer |title= Scientists Say Canadian Bacteria Fossils May Be Earth's Oldest |url= https://www.nytimes.com/2017/03/01/science/earths-oldest-bacteria-fossils.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2017/03/01/science/earths-oldest-bacteria-fossils.html |archive-date=2022-01-01 |url-access=limited |date= 1 March 2017 |work= The New York Times |access-date= 2 March 2017 }}{{cbignore}}</ref><ref name="BBC-20170301">{{cite web |last= Ghosh |first= Pallab |title= Earliest evidence of life on Earth 'found' |url= https://www.bbc.co.uk/news/science-environment-39117523 |work= BBC News |date= 1 March 2017 |access-date= 2 March 2017}} </ref><ref name="4.3b oldest"> {{cite news |last1= Dunham |first1= Will |title= Canadian bacteria-like fossils called oldest evidence of life |url= http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |archive-url= https://web.archive.org/web/20170302114728/http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |archive-date= March 2, 2017 |date= 1 March 2017 |work= Reuters |access-date= 1 March 2017 }} </ref>

|}

=== Archean Eon === {{Main|Archean}} [[File:Acasta gneiss.jpg|thumb|right|240px|Fragment of the Acasta Gneiss exhibited at the Museum of Natural History in Vienna]] [[File:Cyanobacterial-algal mat.jpg|thumb|right|240px|The cyanobacterial-algal mat, salty lake on the White Sea seaside]] [[File:Halobacteria.jpg|thumb|right|240px|''Halobacterium'' sp. strain NRC-1]]

4031 Ma &ndash; 2500 Ma

{| class="wikitable" |- ! Date ! Event |- |4100 Ma |Earliest possible preservation of biogenic carbon.<ref>{{Cite web |date=2015-10-19 |title=4.1-billion-year-old crystal may hold earliest signs of life |url=https://www.sciencenews.org/article/41-billion-year-old-crystal-may-hold-earliest-signs-life |access-date=2023-08-08 |language=en-US}}</ref><ref>{{Cite journal |last1=Bell |first1=Elizabeth A. |last2=Boehnke |first2=Patrick |last3=Harrison |first3=T. Mark |last4=Mao |first4=Wendy L. |date=2015-11-24 |title=Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon |journal=Proceedings of the National Academy of Sciences |language=en |volume=112 |issue=47 |pages=14518–14521 |doi=10.1073/pnas.1517557112 |issn=0027-8424 |pmc=4664351 |pmid=26483481 |bibcode=2015PNAS..11214518B |doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 4100–3800 Ma | Late Heavy Bombardment (LHB): extended barrage by meteoroids impacting the inner planets. Thermal flux from widespread hydrothermal activity during the LHB may have aided abiogenesis and life's early diversification.<ref>{{cite journal |last1=Abramov |first1=Oleg |last2=Mojzsis |first2=Stephen J. |date=May 21, 2009 |title=Microbial habitability of the Hadean Earth during the late heavy bombardment |url=http://isotope.colorado.edu/2009_Abramov_Mojzsis_Nature.pdf |journal=Nature |volume=459 |issue=7245 |pages=419–422 |bibcode=2009Natur.459..419A |doi=10.1038/nature08015 |issn=0028-0836 |pmid=19458721 |s2cid=3304147 |access-date=2015-03-04 |archive-date=2015-11-12 |archive-url=https://web.archive.org/web/20151112140112/http://isotope.colorado.edu/2009_Abramov_Mojzsis_Nature.pdf }}</ref> Possible remains of biotic life were found in 4.1 billion-year-old rocks in Western Australia.<ref name="AP-20151019">{{cite news |last= Borenstein |first= Seth |title= Hints of life on what was thought to be desolate early Earth |url= http://apnews.excite.com/article/20151019/us-sci--earliest_life-a400435d0d.html |date= October 19, 2015 |work= Excite |location= Yonkers, NY |publisher= Mindspark Interactive Network |agency= Associated Press |access-date= 2015-10-20 |archive-date= 2015-10-23 |archive-url= https://web.archive.org/web/20151023200248/http://apnews.excite.com/article/20151019/us-sci--earliest_life-a400435d0d.html }}</ref><ref name="PNAS-20151014-pdf">{{cite journal |last1= Bell |first1= Elizabeth A. |last2= Boehnike |first2=Patrick |last3=Harrison |first3=T. Mark |last4=Mao |first4=Wendy L. |display-authors=3 |date= November 24, 2015 |title= Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon |url= http://www.pnas.org/content/early/2015/10/14/1517557112.full.pdf |journal=Proc. Natl. Acad. Sci. U.S.A. |volume= 112 |issue= 47 |pages= 14518–14521 |doi=10.1073/pnas.1517557112 |issn=0027-8424 |access-date= 2015-12-30 |pmid=26483481 |pmc=4664351|bibcode=2015PNAS..11214518B |doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 4000 Ma | Formation of a greenstone belt of the Acasta Gneiss of the Slave craton in northwest Canada - the oldest known rock belt.<ref name="Bjornerud">{{harvnb|Bjornerud|2005}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 3900–2500 Ma | Cells resembling prokaryotes appear.<ref>{{cite journal |last1= Woese |first1= Carl |author-link1=Carl Woese |last2=Gogarten |first2=J. Peter |author-link2=Johann Peter Gogarten |date= October 21, 1999 |title= When did eukaryotic cells (cells with nuclei and other internal organelles) first evolve? What do we know about how they evolved from earlier life-forms? |url= http://www.scientificamerican.com/article/when-did-eukaryotic-cells/ |journal=Scientific American |issn= 0036-8733 |access-date=2015-03-04}}</ref> These first organisms are believed to have been chemoautotrophs, using carbon dioxide as a carbon source and oxidizing inorganic materials to extract energy. |- valign="TOP" | align="RIGHT" nowrap | 3800 Ma | Formation of a greenstone belt of the Isua complex in western Greenland, whose isotope frequencies suggest the presence of life.<ref name="Bjornerud" /> The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada;<ref>{{cite news|author= Nicole Mortilanno|url= http://www.cbc.ca/news/technology/oldest-record-life-earth-found-quebec-1.4004545|title=Oldest traces of life on Earth found in Quebec, dating back roughly 3.8 billion years |work=CBC News}}</ref> graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland;<ref name="NG-20131208">{{cite journal |last1=Ohtomo |first1=Yoko |last2=Kakegawa |first2=Takeshi |last3=Ishida |first3=Akizumi |last4= Nagase |first4=Toshiro |last5=Rosing |first5=Minik T. |date=January 2014 |title=Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks |journal= Nature Geoscience |volume= 7 |issue= 1 |pages=25–28 |doi=10.1038/ngeo2025 |issn=1752-0894 |display-authors=3 |bibcode=2014NatGe...7...25O}}</ref> and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.<ref name="AP-20131113">{{cite news |last= Borenstein |first= Seth |date= November 13, 2013 |title=Oldest fossil found: Meet your microbial mom |url= http://apnews.excite.com/article/20131113/DAA1VSC01.html |work=Excite |location=Yonkers, NY |publisher= Mindspark Interactive Network |agency= Associated Press |access-date= 2013-11-15}}</ref><ref name="AST-20131108">{{cite journal |last1=Noffke |first1=Nora |author1-link=Nora Noffke |last2=Christian |first2=Daniel |last3=Wacey |first3= David |last4=Hazen |first4=Robert M. |author-link4=Robert Hazen |date=November 8, 2013 |title= Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia |journal= Astrobiology |volume= 13 |issue=12 |pages=1103–1124 |doi=10.1089/ast.2013.1030 |issn=1531-1074 |pmc=3870916 |pmid= 24205812 |bibcode=2013AsBio..13.1103N }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 3800–3500 Ma | Last universal common ancestor (LUCA):<ref>{{cite journal |last= Doolittle |first= W. Ford |author-link= Ford Doolittle |date=February 2000 |title=Uprooting the Tree of Life |url= http://shiva.msu.montana.edu/courses/mb437_537_2004_fall/docs/uprooting.pdf |journal=Scientific American |volume=282 |issue=2 |pages=90–95 |doi=10.1038/scientificamerican0200-90 |issn=0036-8733 |pmid= 10710791 |archive-url= https://web.archive.org/web/20060907081933/http://shiva.msu.montana.edu/courses/mb437_537_2004_fall/docs/uprooting.pdf |archive-date= 2006-09-07 |access-date= 2015-04-05 |bibcode= 2000SciAm.282b..90D }}</ref><ref>{{cite journal |last1= Glansdorff |first1= Nicolas |author2= Ying Xu |last3= Labedan |first3= Bernard |date= July 9, 2008 |title= The Last Universal Common Ancestor: emergence, constitution and genetic legacy of an elusive forerunner |journal= Biology Direct |volume= 3 |issue= 1 |article-number= 29 |doi= 10.1186/1745-6150-3-29 |issn=1745-6150 |pmc=2478661 |pmid=18613974 |bibcode= 2008BiDir...3...29G |doi-access= free }}</ref> split between bacteria and archaea.<ref>{{cite journal |last1=Hahn |first1=Jürgen |last2=Haug |first2= Pat |date=May 1986 |title=Traces of Archaebacteria in ancient sediments |journal=Systematic and Applied Microbiology |volume=7 |issue=2–3 |pages=178–183 |doi=10.1016/S0723-2020(86)80002-9 |bibcode=1986SyApM...7..178H |issn=0723-2020 }}</ref>

Bacteria develop primitive photosynthesis, which at first did not produce oxygen.<ref>{{cite journal |last= Olson |first= John M. |date= May 2006 |title= Photosynthesis in the Archean era |journal= Photosynthesis Research |volume= 88 |issue= 2 |pages= 109–117 |doi= 10.1007/s11120-006-9040-5 |issn= 0166-8595 |pmid=16453059 |bibcode= 2006PhoRe..88..109O |s2cid=20364747 }}</ref> These organisms exploit a proton gradient to generate adenosine triphosphate (ATP), a mechanism used by virtually all subsequent organisms.<ref>{{cite web|url= http://www.nature.com/scitable/topicpage/why-are-cells-powered-by-proton-gradients-14373960|title=Proton Gradient, Cell Origin, ATP Synthase - Learn Science at Scitable|website= www.nature.com}}</ref><ref>{{cite journal |last1= Romano |first1= Antonio H. |last2= Conway |first2= Tyrrell |date= July–September 1996 |title= Evolution of carbohydrate metabolic pathways |journal= Research in Microbiology |volume= 147 |issue=6–7 |pages=448–455 |doi=10.1016/0923-2508(96)83998-2 |issn=0923-2508 |pmid=9084754 |doi-access= free }}</ref><ref>{{cite journal |last=Knowles |first=Jeremy R. |author-link=Jeremy R. Knowles |date=July 1980 |title= Enzyme-Catalyzed Phosphoryl Transfer Reactions |journal=Annual Review of Biochemistry |volume=49 |issue=1 |pages= 877–919 |doi=10.1146/annurev.bi.49.070180.004305 |issn=0066-4154 |pmid=6250450 |bibcode=1980ARBio..49..877K }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 3000 Ma | Photosynthesizing cyanobacteria using water as a reducing agent and producing oxygen as a waste product.<ref name="Buick, R. 2008">{{cite journal |last= Buick |first= Roger |date= August 27, 2008 |title= When did oxygenic photosynthesis evolve? |journal= Philosophical Transactions of the Royal Society B |volume= 363 |issue= 1504 |pages=2731–2743 |doi=10.1098/rstb.2008.0041 |issn= 0962-8436 |pmc=2606769 |pmid=18468984 |bibcode= 2008RSPTB.363.2731B }}</ref> Free oxygen initially oxidizes dissolved iron in the oceans, creating iron ore. Oxygen concentration in the atmosphere slowly rises, poisoning many bacteria and eventually triggering the Great Oxygenation Event. |- valign="TOP" | align="RIGHT" nowrap | 2800 Ma | Oldest evidence for microbial life on land in the form of organic matter-rich paleosols, ephemeral ponds and alluvial sequences, some bearing microfossils.<ref name="Beraldi-Campesi">{{cite journal |last=Beraldi-Campesi |first=Hugo |date= February 23, 2013 |title=Early life on land and the first terrestrial ecosystems |url= http://www.ecologicalprocesses.com/content/pdf/2192-1709-2-1.pdf |journal= Ecological Processes |volume= 2 |issue=1 |page=4 |article-number=1 |doi=10.1186/2192-1709-2-1 |s2cid=44199693 |issn=2192-1709 |doi-access= free |bibcode=2013EcoPr...2....1B }}</ref> |}

=== Proterozoic Eon === [[File:Endomembrane system diagram en (edit).svg|thumb|right|240px|Detail of the eukaryote endomembrane system and its components]] [[File:Mikrofoto.de-Blepharisma japonicum 15.jpg|thumb|right|240px|''Blepharisma japonicum'', a free-living ciliated protozoan]] [[File:DickinsoniaCostata.jpg|thumb|right|240px|''Dickinsonia costata'', an iconic Ediacaran organism, displays the characteristic quilted appearance of Ediacaran enigmata.]] {{Main|Proterozoic}} 2500 Ma &ndash; 539 Ma. Contains the Palaeoproterozoic, Mesoproterozoic and Neoproterozoic eras.

{| class="wikitable" |- ! Date ! Event |- valign="TOP" | align="RIGHT" nowrap | 2500 Ma |Great Oxidation Event led by cyanobacteria's oxygenic photosynthesis.<ref name="Buick, R. 2008" /> Commencement of plate tectonics with old marine crust dense enough to subduct.<ref name="Bjornerud" /> |- valign="TOP" | align="RIGHT" nowrap |2400 Ma | Possible land fungi evidence from molecules. |- valign="TOP" | align="RIGHT" nowrap |2023 Ma |Formation of the Vredefort impact structure, one of the largest and oldest verified impact structures on Earth. The crater is estimated to have been between {{convert|170-300|km|mi}} across when it first formed.<ref>{{Cite journal |last1=Huber |first1=M. S. |last2=Kovaleva |first2=E. |last3=Rae |first3=A. S. P |last4=Tisato |first4=N. |last5=Gulick |first5=S. P. S |date=August 2023 |title=Can Archean Impact Structures Be Discovered? A Case Study From Earth's Largest, Most Deeply Eroded Impact Structure |journal=Journal of Geophysical Research: Planets |volume=128 |issue=8 |article-number=e2022JE007721 |doi=10.1029/2022JE007721 |issn=2169-9097 |doi-access=free|bibcode=2023JGRE..12807721H |hdl=20.500.11820/eefdc78e-ee46-446d-886f-2ab811603020 |hdl-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | By 1850 Ma | Eukaryotic cells, containing membrane-bound organelles with diverse functions, probably derived from prokaryotes engulfing each other via phagocytosis. (See Symbiogenesis and Endosymbiont). Bacterial viruses (bacteriophages) emerge before or soon after the divergence of the prokaryotic and eukaryotic lineages.<ref>{{cite journal |last1=Bernstein |first1=Harris |last2=Bernstein |first2=Carol |date=May 1989 |title=Bacteriophage T4 genetic homologies with bacteria and eucaryotes |journal=Journal of Bacteriology |volume=171 |issue=5 |pages=2265–2270 |issn=0021-9193 |pmc=209897 |pmid=2651395 |doi=10.1128/jb.171.5.2265-2270.1989 }}</ref> Red beds show an oxidising atmosphere, favouring the spread of eukaryotic life.<ref>{{harvnb|Bjornerud|2005|p=151}}</ref><ref>{{cite journal |last1=Knoll |first1=Andrew H. |last2=Javaux |first2=Emmanuelle J. |last3=Hewitt |first3=David |last4=Cohen |first4=Phoebe |display-authors=3 |date=June 29, 2006 |title=Eukaryotic organisms in Proterozoic oceans |journal=Philosophical Transactions of the Royal Society B |volume=361 |issue=1470 |pages=1023–1038 |doi=10.1098/rstb.2006.1843 |issn=0962-8436 |pmc=1578724 |pmid=16754612}}</ref><ref>{{cite journal |last=Fedonkin |first=Mikhail A. |author-link=Mikhail Fedonkin |date=March 31, 2003 |title=The origin of the Metazoa in the light of the Proterozoic fossil record |journal=Paleontological Research |volume=7 |issue=1 |pages=9–41 |doi=10.2517/prpsj.7.9 |s2cid=55178329 |issn=1342-8144 |doi-access=free |bibcode=2003PalRe...7....9F }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 1500 Ma |Volyn biota, a collection of exceptionally well-preserved microfossils with varying morphologies.<ref name=fra2022>{{cite journal |author=Franz G., Lyckberg P., Khomenko V., Chournousenko V., Schulz H.-M., Mahlstedt N., Wirth R., Glodny J., Gernert U., Nissen J. |title=Fossilization of Precambrian microfossils in the Volyn pegmatite, Ukraine |journal=Biogeosciences |volume=19 |issue=6 |date=2022 |pages=1795–1811 |doi=10.5194/bg-19-1795-2022 |bibcode=2022BGeo...19.1795F |url=https://bg.copernicus.org/articles/19/1795/2022/bg-19-1795-2022.pdf |doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 1300 Ma | Earliest land fungi.<ref>{{cite web |url=http://science.psu.edu/news-and-events/2001-news/Hedges8-2001.htm |title=First Land Plants and Fungi Changed Earth's Climate, Paving the Way for Explosive Evolution of Land Animals, New Gene Study Suggests |work=science.psu.edu |access-date=10 April 2018 |archive-url=https://web.archive.org/web/20180408205932/http://science.psu.edu/news-and-events/2001-news/Hedges8-2001.htm |archive-date=2018-04-08 |quote=The researchers found that land plants had evolved on Earth by about 700 million years ago and land fungi by about 1,300 million years ago — much earlier than previous estimates of around 480 million years ago, which were based on the earliest fossils of those organisms.}}</ref> |- valign="TOP" | align="RIGHT" nowrap | By 1200 Ma | Meiosis and sexual reproduction in single-celled eukaryotes, possibly even in the common ancestor of all eukaryotes<ref>{{harvnb|Bernstein|Bernstein|Michod|2012|pp=1–50}}</ref> or in the RNA world.<ref>{{cite journal |last1=Bernstein |first1=Harris |last2=Byerly |first2=Henry C. |last3=Hopf |first3=Frederic A. |last4=Michod |first4=Richard E. |date=October 7, 1984 |title=Origin of sex |journal=Journal of Theoretical Biology |volume=110 |issue=3 |pages=323–351 |doi=10.1016/S0022-5193(84)80178-2 |issn=0022-5193 |pmid=6209512 |bibcode=1984JThBi.110..323B }}</ref> Sexual reproduction may have increased the rate of evolution.<ref name="dateref">{{cite journal |last=Butterfield |first=Nicholas J. |date=Summer 2000 |title=''Bangiomorpha pubescens'' n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes |url=http://paleobiol.geoscienceworld.org/content/26/3/386.abstract |journal=Paleobiology |volume=26 |issue=3 |pages=386–404 |doi=10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2 |bibcode=2000Pbio...26..386B |s2cid=36648568 |issn=0094-8373 }}</ref> |- valign="TOP" | align='RIGHT' nowrap | By 1000 Ma | First non-marine eukaryotes move onto land. They were photosynthetic and multicellular, indicating that plants evolved much earlier than originally thought.<ref>{{cite journal |title=Earth's earliest non-marine eukaryotes |journal=Nature |volume=473 |issue=7348 |pages=505–509 |doi=10.1038/nature09943 |pmid=21490597 |date=26 May 2011|bibcode=2011Natur.473..505S |last1=Strother |first1=Paul K. |last2=Battison |first2=Leila |last3=Brasier |first3=Martin D. |last4=Wellman |first4=Charles H. |s2cid=4418860 }}</ref> |- valign="TOP' | align="RIGHT" nowrap | 750 Ma | Beginning of animal evolution.<ref name="NYT-20191127">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Is This the First Fossil of an Embryo? - Mysterious 609-million-year-old balls of cells may be the oldest animal embryos — or something else entirely. |url=https://www.nytimes.com/2019/11/27/science/fossil-embryo-paleontology-caveaspharea.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2019/11/27/science/fossil-embryo-paleontology-caveaspharea.html |archive-date=2022-01-01 |url-access=limited |date=27 November 2019 |work=The New York Times |access-date=28 November 2019 }}{{cbignore}}</ref><ref name="BE-20161205">{{cite journal |author=Cunningham, John A. |display-authors=et al. |title=The origin of animals: Can molecular clocks and the fossil record be reconciled? |date=5 December 2016 |journal=BioEssays |volume=39 |issue=1 |article-number=e201600120 |doi=10.1002/bies.201600120 |pmid=27918074 |doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 720&ndash;630 Ma | Possible global glaciation<ref name="Hoffman1998">{{cite journal |last1=Hoffman |first1=Paul F. |author-link1=Paul F. Hoffman |last2=Kaufman |first2=Alan J. |last3=Halverson |first3=Galen P. |last4=Schrag |first4=Daniel P. |author-link4=Daniel P. Schrag |date=August 28, 1998 |title=A Neoproterozoic Snowball Earth |url=http://www.snowballearth.org/pdf/Hoffman_Science1998.pdf |journal=Science |volume=281 |issue=5381 |pages=1342–1346 |bibcode=1998Sci...281.1342H |doi=10.1126/science.281.5381.1342 |issn=0036-8075 |pmid=9721097 |s2cid=13046760 |access-date=2007-05-04 }}</ref><ref>{{harvnb|Kirschvink|1992|pp=51–52}}</ref> which increased the atmospheric oxygen and decreased carbon dioxide, and was either ''caused'' by land plant evolution<ref>{{cite web |title=First Land Plants and Fungi Changed Earth's Climate, Paving the Way for Explosive Evolution of Land Animals, New Gene Study Suggests |url=https://www.sciencedaily.com/releases/2001/08/010810070021.htm |access-date=25 May 2022 |work=www.sciencedaily.com}}</ref> or ''resulted'' in it.<ref name="Zarsky-et-al-2022">{{cite journal | last1=Žárský | first1=J. | last2=Žárský | first2=V. | last3=Hanáček | first3=M. | last4=Žárský | first4=V. | title=Cryogenian Glacial Habitats as a Plant Terrestrialisation Cradle – The Origin of the Anydrophytes and Zygnematophyceae Split | journal=Frontiers in Plant Science | publisher=Frontiers | volume=12 | date=2022-01-27 | article-number=735020 | issn=1664-462X | doi=10.3389/fpls.2021.735020| pmid=35154170 | pmc=8829067 | doi-access=free | bibcode=2022FrPS...1235020Z }}</ref> Opinion is divided on whether it increased or decreased biodiversity or the rate of evolution.<ref>{{cite journal |last1=Boyle |first1=Richard A. |last2=Lenton |first2=Timothy M. |author-link2=Tim Lenton |last3=Williams |first3=Hywel T. P. |date=December 2007 |title=Neoproterozoic 'snowball Earth' glaciations and the evolution of altruism |url=http://researchpages.net/media/resources/2007/06/21/richtimhywelfinal.pdf |journal=Geobiology |volume=5 |issue=4 |pages=337–349 |doi=10.1111/j.1472-4669.2007.00115.x |bibcode=2007Gbio....5..337B |s2cid=14827354 |issn=1472-4677 |archive-url=https://web.archive.org/web/20080910213718/http://researchpages.net/media/resources/2007/06/21/richtimhywelfinal.pdf |archive-date=2008-09-10 |access-date=2015-03-09 }}</ref><ref>{{cite journal |last1=Corsetti |first1=Frank A. |last2=Awramik |first2=Stanley M. |author-link2=Stanley Awramik |last3=Pierce |first3=David |date=April 15, 2003 |title=A complex microbiota from snowball Earth times: Microfossils from the Neoproterozoic Kingston Peak Formation, Death Valley, USA |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=100 |issue=8 |pages=4399–4404 |bibcode=2003PNAS..100.4399C |doi=10.1073/pnas.0730560100 |issn=0027-8424 |pmc=153566 |pmid=12682298 |doi-access=free }}</ref><ref name="Corsetti2006">{{cite journal |last1=Corsetti |first1=Frank A. |last2=Olcott |first2=Alison N. |last3=Bakermans |first3=Corien |date=March 22, 2006 |title=The biotic response to Neoproterozoic snowball Earth |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=232 |issue=2–4 |pages=114–130 |doi=10.1016/j.palaeo.2005.10.030 |issn=0031-0182 |bibcode=2006PPP...232..114C }}</ref> |- | align="RIGHT" nowrap | 600 Ma | Accumulation of atmospheric oxygen allows the formation of an ozone layer.<ref name="Formation of the Ozone Layer">{{cite web |url=http://disc.sci.gsfc.nasa.gov/ozone/additional/science-focus/about-ozone/ozone_formation.shtml |title=Formation of the Ozone Layer |date=September 9, 2009 |work=Goddard Earth Sciences Data and Information Services Center |publisher=NASA |access-date=2013-05-26}}</ref> Previous land-based life would probably have required other chemicals to attenuate ultraviolet radiation.<ref name="Beraldi-Campesi" /> |- valign="TOP" | align="Right" nowrap | 580&ndash;542 Ma | Ediacaran biota, the first large, complex aquatic multicellular organisms.<ref>{{cite web |url=http://geol.queensu.ca/people/narbonne/recent_pubs1.html |title=The Origin and Early Evolution of Animals |last=Narbonne |first=Guy |date=January 2008 |publisher=Queen's University |location=Kingston, Ontario, Canada |access-date=2007-03-10 |archive-url=https://web.archive.org/web/20150724081804/http://geol.queensu.ca/people/narbonne/recent_pubs1.html |archive-date=2015-07-24 }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 580&ndash;500 Ma | Cambrian explosion: most modern animal phyla appear.<ref name="BerkeleyCambrian">{{cite web |url=http://www.ucmp.berkeley.edu/cambrian/cambrian.php |title=The Cambrian Period |last1=Waggoner |first1=Ben M. |last2=Collins |first2=Allen G. |last3=Hsu |first3=Karen |last4=Kang |first4=Myun |last5=Lavarias |first5=Amy |last6=Prabaker |first6=Kavitha |last7=Skaggs |first7=Cody |date=November 22, 1994 |editor1-last=Rieboldt |editor1-first=Sarah |editor2-last=Smith |editor2-first=Dave |website=Tour of geologic time |publisher=University of California Museum of Paleontology |location=Berkeley, CA |type=Online exhibit |display-authors=2 |access-date=2015-03-09}}</ref><ref name="BristolUCEtiming">{{cite web |url=http://palaeo.gly.bris.ac.uk/Palaeofiles/Cambrian/timing/timing.html |title=Timing |last=Lane |first=Abby |date=January 20, 1999 |website=The Cambrian Explosion |publisher=University of Bristol |location=Bristol, England |access-date=2015-03-09}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 550&ndash;540 Ma | Ctenophora (comb jellies),<ref>{{Cite journal |last1=Chen |first1=Jun-Yuan |last2=Schopf |first2=J. William |last3=Bottjer |first3=David J. |last4=Zhang |first4=Chen-Yu |last5=Kudryavtsev |first5=Anatoliy B. |last6=Tripathi |first6=Abhishek B. |last7=Wang |first7=Xiu-Qiang |last8=Yang |first8=Yong-Hua |last9=Gao |first9=Xiang |last10=Yang |first10=Ying |date=2007-04-10 |title=Raman spectra of a Lower Cambrian ctenophore embryo from southwestern Shaanxi, China |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=104 |issue=15 |pages=6289–6292 |doi=10.1073/pnas.0701246104 |issn=0027-8424 |pmc=1847456 |pmid=17404242|bibcode=2007PNAS..104.6289C |doi-access=free }}</ref> Porifera (sponges),<ref>{{Cite journal |last1=Müller |first1=W. E. G. |last2=Jinhe Li |last3=Schröder |first3=H. C. |last4=Li Qiao |last5=Xiaohong Wang |date=2007-05-03 |title=The unique skeleton of siliceous sponges (Porifera; Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic: a review |url=https://bg.copernicus.org/articles/4/219/2007/ |journal=Biogeosciences |language=English |volume=4 |issue=2 |pages=219–232 |doi=10.5194/bg-4-219-2007 |bibcode=2007BGeo....4..219M |s2cid=15471191 |issn=1726-4170|doi-access=free }}</ref> Anthozoa (corals and sea anemones),<ref>{{Cite web |date=2018-12-11 |title=Corals and sea anemones (anthozoa) |url=https://nationalzoo.si.edu/animals/corals-and-sea-anemones-anthozoa |access-date=2022-09-24 |website=Smithsonian's National Zoo |language=en}}</ref> ''Ikaria wariootia'' (an early Bilaterian).<ref>{{Cite journal |last=Grazhdankin |first=Dima |date=February 8, 2016 |title=Patterns of distribution in the Ediacaran biotas: facies versus biogeography and evolution |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/patterns-of-distribution-in-the-ediacaran-biotas-facies-versus-biogeography-and-evolution/E1A8C6052128EB081CB260731B5628A6 |journal=Paleobiology |language=en |volume=30 |issue=2 |pages=203–221 |doi=10.1666/0094-8373(2004)030<0203:PODITE>2.0.CO;2 |s2cid=129376371 |issn=0094-8373|url-access=subscription }}</ref> |}

=== Phanerozoic Eon === {{Main|Phanerozoic}} {{More citations needed|section|date=September 2022}} 539 Ma &ndash; present

The Phanerozoic Eon (Greek: period of well-displayed life) marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. It is subdivided into three eras, the Paleozoic, Mesozoic and Cenozoic, with major mass extinctions at division points.

==== Palaeozoic Era ==== {{Main|Paleozoic}} 538.8 Ma &ndash; 251.9 Ma and contains the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods. [[File:Nautilus belauensis profile.jpg|240px|thumb|With only a handful of species surviving today, the Nautiloids flourished during the early Paleozoic era, from the Late Cambrian, where they constituted the main predatory animals.<ref>{{cite journal |last1=Lindgren |first1=A.R. |last2=Giribet |first2=G. |last3=Nishiguchi |first3=M.K. |title=A combined approach to the phylogeny of Cephalopoda (Mollusca) |journal=Cladistics |date=2004 |volume=20 |issue=5 |pages=454–486 |url=http://faculty.uml.edu/rhochberg/hochberglab/Courses/InvertZool/Cephalopod%20phylogeny.pdf |archive-url=https://web.archive.org/web/20150210223626/http://faculty.uml.edu/rhochberg/hochberglab/Courses/InvertZool/Cephalopod%20phylogeny.pdf |archive-date=2015-02-10 |doi=10.1111/j.1096-0031.2004.00032.x |pmid=34892953 |citeseerx=10.1.1.693.2026 |s2cid=85975284 }}</ref>]] [[File:Haikouichthys 3d.png|240px|thumb|''Haikouichthys'', a jawless fish, is popularized as one of the earliest fishes and probably a basal chordate or a basal craniate.<ref>{{cite web |url=http://www.palaeos.com/Paleozoic/Cambrian/Cambrian.2.html |title=Palaeos Paleozoic: Cambrian: The Cambrian Period - 2 |access-date=2009-04-20 |archive-url=https://web.archive.org/web/20090429021119/http://www.palaeos.com/Paleozoic/Cambrian/Cambrian.2.html |archive-date=2009-04-29 }}</ref> ]] [[File:Sa-fern.jpg|240px|thumb|Ferns first appear in the fossil record about 360 million years ago in the late Devonian period.<ref>{{cite web |url=http://www.ucmp.berkeley.edu/plants/pterophyta/pteridofr.html |title=Pteridopsida: Fossil Record |publisher=University of California Museum of Paleontology | access-date=2014-03-11 }}</ref>]] [[File:Dimetrodon grandis 3D Model Reconstruction.png|thumb|240px|Synapsids such as ''Dimetrodon'' were the largest terrestrial vertebrates in the Permian period, 299 to 251 million years ago.]] {| class="wikitable" |- ! Date ! Event |- valign="TOP" | align="RIGHT" nowrap | 535 Ma | Major diversification of living things in the oceans: arthropods (e.g. trilobites, crustaceans), chordates, echinoderms, molluscs, brachiopods, foraminifers and radiolarians, etc. |- valign="TOP" | align="RIGHT" nowrap | 530 Ma | The first known footprints on land date to 530 Ma.<ref>{{cite journal |last=Clarke |first=Tom |date=April 30, 2002 |title=Oldest fossil footprints on land |url=http://www.nature.com/news/2002/020430/full/news020429-2.html |journal=Nature |doi=10.1038/news020429-2 |issn=1744-7933 |access-date=2015-03-09 |quote=The oldest fossils of footprints ever found on land hint that animals may have beaten plants out of the primordial seas. Lobster-sized, centipede-like animals made the prints wading out of the ocean and scuttling over sand dunes about 530 million years ago. Previous fossils indicated that animals didn't take this step until 40 million years later.|url-access=subscription }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 520 Ma | Earliest graptolites.<ref>{{Cite web |title=Graptolites |url=https://www.bgs.ac.uk/discovering-geology/fossils-and-geological-time/graptolites/ |access-date=2022-09-24 |website=British Geological Survey |language=en-GB}}</ref> |- | align="RIGHT" nowrap | 511 Ma |Earliest crustaceans.<ref>{{Cite web |last=Leutwyler |first=Kristin |title=511-Million-Year-Old Fossil Suggests Pre-Cambrian Origins for Crustaceans |url=https://www.scientificamerican.com/article/511-million-year-old-foss/ |access-date=2022-09-24 |website=Scientific American |language=en}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 505 Ma | Fossilization of the Burgess Shale |- | align="RIGHT" nowrap | 500 Ma |Jellyfish have existed since at least this time. |- valign="TOP" | align="RIGHT" nowrap | 485 Ma | First vertebrates with true bones (jawless fishes). |- valign="TOP" | align="RIGHT" nowrap | 450 Ma | First complete conodonts and echinoids appear. |- valign="TOP" | align="RIGHT" nowrap | 440 Ma | First agnathan fishes: Heterostraci, Galeaspida, and Pituriaspida. |- valign="TOP" | align="RIGHT" nowrap | 420 Ma | Earliest ray-finned fishes, trigonotarbid arachnids, and land scorpions.<ref name="Garwood">{{cite journal |last1=Garwood |first1=Russell J. |last2=Edgecombe |first2=Gregory D. |date=September 2011 |title=Early Terrestrial Animals, Evolution, and Uncertainty |journal=Evolution: Education and Outreach |volume=4 |issue=3 |pages=489–501 |doi=10.1007/s12052-011-0357-y |issn=1936-6426 |doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 410 Ma | First signs of teeth in fish. Earliest Nautilida, lycophytes, and trimerophytes. |- valign="TOP" | align="RIGHT" nowrap="" | 488&ndash;400 Ma | First cephalopods (nautiloids)<ref>{{Cite journal |last1=Landing |first1=Ed |last2=Westrop |first2=Stephen R. |title=Lower Ordovician Faunas, Stratigraphy, and Sea-Level History of the Middle Beekmantown Group, Northeastern New York |date=September 1, 2006 |url=https://bioone.org/journals/journal-of-paleontology/volume-80/issue-5/0022-3360_2006_80_958_LOFSAS_2.0.CO_2/LOWER-ORDOVICIAN-FAUNAS-STRATIGRAPHY-AND-SEA-LEVEL-HISTORY-OF-THE/10.1666/0022-3360(2006)80[958:LOFSAS]2.0.CO;2.full |journal=Journal of Paleontology |volume=80 |issue=5 |pages=958–980 |doi=10.1666/0022-3360(2006)80[958:LOFSAS]2.0.CO;2 |s2cid=130848432 |issn=0022-3360|url-access=subscription }}</ref> and chitons.<ref>{{Cite journal |last1=Serb |first1=Jeanne M. |last2=Eernisse |first2=Douglas J. |date=September 25, 2008 |title=Charting Evolution's Trajectory: Using Molluscan Eye Diversity to Understand Parallel and Convergent Evolution |journal=Evolution: Education and Outreach |language=en |volume=1 |issue=4 |pages=439–447 |doi=10.1007/s12052-008-0084-1 |s2cid=2881223 |issn=1936-6434|doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 395 Ma | First lichens, stoneworts. Earliest harvestmen, mites, hexapods (springtails) and ammonoids. The earliest known tracks on land named the Zachelmie trackways which are possibly related to icthyostegalians.<ref>{{Cite journal |last1=Niedźwiedzki |first1=Grzegorz |last2=Szrek |first2=Piotr |last3=Narkiewicz |first3=Katarzyna |last4=Narkiewicz |first4=Marek |last5=Ahlberg |first5=Per E. |date=January 1, 2010 |title=Tetrapod trackways from the early Middle Devonian period of Poland |url=https://d1wqtxts1xzle7.cloudfront.net/46752909/trackways-with-cover-page-v2.pdf?Expires=1664076708&Signature=T90exV-98rO1WUlSoLdNXTzzvqxsI-rCpzhxd1xC6Pt2wc-hH2xVdXEP57MFHFhPw5yfMK9kf5bRJ6WTM1WH-jXOTPfHoKUJVPH-s50O0~h6F0yg1HemExF546SgHoUEJ4a-HVpyzB2IXHNB8atvNjpfHTburCWCtaN8h4-Axs8yadT5uS8rNSgBgOZeXYJdHYk9D3FZ3vuEUC44QTxZKio2qF7G32CvptPzkd7D8IPzcqIUymSeErAXy9zTp1Ep2Vc9ttecV4DqNuV0VSGewUek-JvvBfI4gwaRJxOdZCvpoyDVRGfE5~xNYcGvmZr1WsAnHTOMRNmYDxGklQ52fw__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA |journal=Nature |language=en |volume=463 |issue=7277 |pages=43–48 |doi=10.1038/nature08623 |pmid=20054388 |bibcode=2010Natur.463...43N |s2cid=4428903 |issn=1476-4687 |access-date=September 25, 2022 |archive-date=September 25, 2022 |archive-url=https://web.archive.org/web/20220925024303/https://d1wqtxts1xzle7.cloudfront.net/46752909/trackways-with-cover-page-v2.pdf?Expires=1664076708&Signature=T90exV-98rO1WUlSoLdNXTzzvqxsI-rCpzhxd1xC6Pt2wc-hH2xVdXEP57MFHFhPw5yfMK9kf5bRJ6WTM1WH-jXOTPfHoKUJVPH-s50O0~h6F0yg1HemExF546SgHoUEJ4a-HVpyzB2IXHNB8atvNjpfHTburCWCtaN8h4-Axs8yadT5uS8rNSgBgOZeXYJdHYk9D3FZ3vuEUC44QTxZKio2qF7G32CvptPzkd7D8IPzcqIUymSeErAXy9zTp1Ep2Vc9ttecV4DqNuV0VSGewUek-JvvBfI4gwaRJxOdZCvpoyDVRGfE5~xNYcGvmZr1WsAnHTOMRNmYDxGklQ52fw__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA }}</ref> |- | align="RIGHT" nowrap | 375 Ma |Tiktaalik, a lobe-finned fish with some anatomical features similar to early tetrapods. It has been suggested to be a transitional species between fish and tetrapods.<ref>{{Cite web |title=Details of Evolutionary Transition from Fish to Land Animals Revealed |url=https://www.nsf.gov/news/news_summ.jsp?cntn_id=112416 |access-date=2022-09-25 |website=www.nsf.gov |language=English}}</ref> |- | align="RIGHT" nowrap | 365 Ma |''Acanthostega'' is one of the earliest vertebrates capable of walking.<ref>{{Cite journal |last=Clack |first=Jennifer A. |date=November 21, 2005 |title=Getting a Leg Up on Land |url=http://sciam.com/print_version.cfm?articleID=000DC8B8-EA15-137C-AA1583414B7F0000 |archive-url=https://web.archive.org/web/20070225023805/http://sciam.com/print_version.cfm?articleID=000DC8B8-EA15-137C-AA1583414B7F0000 |archive-date=2007-02-25 |journal=Scientific American|volume=293 |issue=6 |pages=100–107 |doi=10.1038/scientificamerican1205-100 |pmid=16323697 |bibcode=2005SciAm.293f.100C }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 363 Ma | By the start of the Carboniferous Period, the Earth begins to resemble its present state. Insects roamed the land and would soon take to the skies; sharks swam the oceans as top predators,<ref>{{cite web |url=http://www.elasmo-research.org/education/evolution/evol_s_predator.htm |title=Evolution of a Super Predator |last=Martin |first=R. Aidan |website=Biology of Sharks and Rays |publisher=ReefQuest Centre for Shark Research |location=North Vancouver, BC, Canada |access-date=2015-03-10 |quote=The ancestry of sharks dates back more than 200 million years before the earliest known dinosaur.}}</ref> and vegetation covered the land, with seed-bearing plants and forests soon to flourish. Four-limbed tetrapods gradually gain adaptations which will help them occupy a terrestrial life-habit. |- valign="TOP" | align="RIGHT" nowrap | 360 Ma | First crabs and ferns. Land flora dominated by seed ferns. The Xinhang forest grows around this time.<ref>{{Cite web|url=http://www.sci-news.com/paleontology/xinhang-forest-07484.html|title=Devonian Fossil Forest Unearthed in China {{!}} Paleontology {{!}} Sci-News.com|website=Breaking Science News {{!}} Sci-News.com|language=en-US|access-date=2019-09-28}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 350 Ma | First large sharks, ratfishes, and hagfish; first crown tetrapods (with five digits and no fins and scales). |- valign="TOP" | align="RIGHT" nowrap | 350 Ma | Diversification of amphibians.<ref>{{Cite web |title=Amphibia |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=36319&is_real_user=1 |access-date=2022-10-07 |website=paleobiodb.org}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 325-335 Ma | First Reptiliomorpha.<ref>{{cite journal|last1=Benton|first1=M.J.|last2=Donoghue|first2=P.C.J.|year=2006|title=Palaeontological evidence to date the tree of life|journal=Molecular Biology and Evolution|volume=24|issue=1|pages=26–53|doi=10.1093/molbev/msl150|pmid=17047029|doi-access=free}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 330-320 Ma | First amniote vertebrates (''Paleothyris'').<ref>{{Cite web |title=Origin and Early Evolution of Amniotes {{!}} Frontiers Research Topic |url=https://www.frontiersin.org/research-topics/14947/origin-and-early-evolution-of-amniotes#:~:text=Amniotes%20first%20appeared%20in%20the%20fossil%20record%20about%20318%20million,attention%20over%20the%20past%20decades. |access-date=2022-10-07 |website=www.frontiersin.org}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 320 Ma | Synapsids (precursors to mammals) separate from sauropsids (reptiles) in late Carboniferous.<ref name="Amniota">{{cite web |url=http://www.palaeos.org/Amniota |title=Amniota |website=Palaeos |access-date=2015-03-09}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 305 Ma | The Carboniferous rainforest collapse occurs, causing a minor extinction event, as well as paving the way for amniotes to become dominant over amphibians and seed plants over ferns and lycophytes. First diapsid reptiles (e.g. ''Petrolacosaurus''). |- valign="TOP" | align="RIGHT" nowrap | 280 Ma | Earliest beetles, seed plants and conifers diversify while lepidodendrids and sphenopsids decrease. Terrestrial temnospondyl amphibians and pelycosaurs (e.g. ''Dimetrodon'') diversify in species. |- valign="TOP" | align="RIGHT" nowrap | 275 Ma | Therapsid synapsids separate from pelycosaur synapsids. |- | align="RIGHT" nowrap | 265 Ma |Gorgonopsians appear in the fossil record.<ref>{{Cite journal |last=Kemp |first=T. S. |date=February 16, 2006 |title=The origin and early radiation of the therapsid mammal-like reptiles: a palaeobiological hypothesis |journal=Journal of Evolutionary Biology |language=en |volume=19 |issue=4 |pages=1231–1247 |doi=10.1111/j.1420-9101.2005.01076.x |pmid=16780524 |s2cid=3184629 |issn=1010-061X|doi-access=free }}</ref> |- valign="TOP" | align="RIGHT" nowrap | 251.9&ndash;251.4 Ma | The Permian–Triassic extinction event eliminates over 90-95% of marine species. Terrestrial organisms were not as seriously affected as the marine biota. This "clearing of the slate" may have led to an ensuing diversification, but life on land took 30 million years to completely recover.<ref name="SahneyBenton2008RecoveryFromProfoundExtinction">{{cite journal |last1=Sahney |first1=Sarda |last2=Benton |first2=Michael J. |author-link2=Michael Benton |date=April 7, 2008 |title=Recovery from the most profound mass extinction of all time |journal=Proceedings of the Royal Society B |volume=275 |issue=1636 |pages=759–765 |doi=10.1098/rspb.2007.1370 |issn=0962-8452 |pmc=2596898 |pmid=18198148 }}</ref> |}

==== Mesozoic Era ==== {{Main|Mesozoic}} [[File:Utatsusaurus BW.jpg|thumb|right|240px|''Utatsusaurus'' is the earliest-known ichthyopterygian.]] [[File:Plateosaurus panorama.jpg|thumb|right|240px|''Plateosaurus engelhardti'']] [[File:Cycas circinalis.jpg|thumb|right|240px|''Cycas circinalis'']] [[File:Tyrannosaurus Rex Jane.jpg|thumb|240px|For about 150 million years, dinosaurs were the dominant land animals on Earth.]] From 251.9 Ma to 66 Ma and containing the Triassic, Jurassic and Cretaceous periods. {| class="wikitable" |- ! Date ! Event |- valign="TOP" | align="RIGHT" nowrap |250 Ma | Mesozoic marine revolution begins: increasingly well adapted and diverse predators stress sessile marine groups; the "balance of power" in the oceans shifts dramatically as some groups of prey adapt more rapidly and effectively than others. |- |- valign="TOP" | align="RIGHT" nowrap | 250 Ma |''Triadobatrachus massinoti'' is the earliest known frog. |- |- valign="TOP" | align="RIGHT" nowrap | 248 Ma |Sturgeon and paddlefish (Acipenseridae) first appear. |- valign="TOP" | align="RIGHT" nowrap | 245 Ma | Earliest ichthyosaurs |- valign="TOP" | align="RIGHT" nowrap | 240 Ma | Increase in diversity of cynodonts and rhynchosaurs |- valign="TOP" | align="RIGHT" nowrap | 225 Ma | Earliest dinosaurs (prosauropods), first cardiid bivalves, diversity in cycads, bennettitaleans, and conifers. First teleost fishes. First mammals (''Adelobasileus''). |- valign="TOP" | align="RIGHT" nowrap | 220 Ma | Seed-producing Gymnosperm forests dominate the land; herbivores grow to huge sizes to accommodate the large guts necessary to digest the nutrient-poor plants.{{Citation needed|date=August 2007}} First flies and turtles (''Odontochelys''). First coelophysoid dinosaurs. First mammals from small-sized cynodonts, which transitioned towards a nocturnal, insectivorous, and endothermic lifestyle. |- |- valign="TOP" | align="RIGHT" nowrap |205 Ma |Massive Triassic/Jurassic extinction. It wipes out all pseudosuchians except crocodylomorphs, who transitioned to an aquatic habitat, while dinosaurs took over the land and pterosaurs filled the air. |- valign="TOP" | style="text-align:RIGHT;" nowrap=""| 200 Ma | First accepted evidence for viruses infecting eukaryotic cells (the group Geminiviridae).<ref>{{cite web |url=http://www.mcb.uct.ac.za/tutorial/virorig.html |title=Origins of Viruses |last=Rybicki |first=Ed |date=April 2008 |website=Introduction of Molecular Virology |publisher=University of Cape Town |location=Cape Town, Western Cape, South Africa |type=Lecture |access-date=2015-03-10 |quote=Viruses of nearly all the major classes of organisms - animals, plants, fungi and bacteria / archaea - probably evolved with their hosts in the seas, given that most of the evolution of life on this planet has occurred there. This means that viruses also probably emerged from the waters with their different hosts, during the successive waves of colonisation of the terrestrial environment. |archive-url=https://web.archive.org/web/20090509094459/http://www.mcb.uct.ac.za/tutorial/virorig.html |archive-date=2009-05-09 }}</ref> However, viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon. Major extinctions in terrestrial vertebrates and large amphibians. Earliest examples of armoured dinosaurs. |- valign="TOP" | align="RIGHT" nowrap | 195 Ma | First pterosaurs with specialized feeding (''Dorygnathus''). First sauropod dinosaurs. Diversification in small, ornithischian dinosaurs: heterodontosaurids, fabrosaurids, and scelidosaurids. |- valign="TOP" | align="RIGHT" nowrap | 190 Ma | Pliosauroids appear in the fossil record. First lepidopteran insects (''Archaeolepis''), hermit crabs, modern starfish, irregular echinoids, corbulid bivalves, and tubulipore bryozoans. Extensive development of sponge reefs. |- valign="TOP" | align="RIGHT" nowrap | 176 Ma | First Stegosaurian dinosaurs. |- valign="TOP" | align="RIGHT" nowrap | 170 Ma | Earliest salamanders, newts, cryptoclidids, elasmosaurid plesiosaurs, and cladotherian mammals. Sauropod dinosaurs diversify. |- valign="TOP" | align="RIGHT" nowrap | 168 Ma | First lizards. |- valign="TOP" | align="RIGHT" nowrap | 165 Ma | First rays and glycymeridid bivalves. First vampire squids.<ref>{{Cite web|url=https://oceanservice.noaa.gov/facts/vampire-squid-fish.html|title=What are the vampire squid and the vampire fish?|last=US Department of Commerce|first=National Oceanic and Atmospheric Administration|website=oceanservice.noaa.gov|language=EN-US|access-date=2019-09-27}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 163 Ma | Pterodactyloid pterosaurs first appear.<ref>{{cite news |last=Dell'Amore |first=Christine |date=April 24, 2014 |title=Meet Kryptodrakon: Oldest Known Pterodactyl Found in China |url=http://news.nationalgeographic.com/news/2014/04/140424-pterodactyl-pterosaur-china-oldest-science-animals/ |archive-url=https://web.archive.org/web/20140425022505/http://news.nationalgeographic.com/news/2014/04/140424-pterodactyl-pterosaur-china-oldest-science-animals/ |archive-date=April 25, 2014 |work=National Geographic News |location=Washington, D.C. |publisher=National Geographic Society |access-date=2014-04-25}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 161 Ma | Ceratopsian dinosaurs appear in the fossil record (''Yinlong'') and the oldest known eutherian mammal: ''Juramaia''. |- valign="TOP" | align="RIGHT" nowrap | 160 Ma | Multituberculate mammals (genus ''Rugosodon'') appear in eastern China. |- valign="TOP" | align="RIGHT" nowrap | 155 Ma | First blood-sucking insects (ceratopogonids), rudist bivalves, and cheilostome bryozoans. ''Archaeopteryx'', a possible ancestor to the birds, appears in the fossil record, along with triconodontid and symmetrodont mammals. Diversity in stegosaurian and theropod dinosaurs. |- valign="TOP" | align="RIGHT" nowrap | 131 Ma |First pine trees. |- valign="TOP" | align="RIGHT" nowrap | 140 Ma |Orb-weaver spiders appear. |- valign="TOP" | align="RIGHT" nowrap | 135 Ma | Rise of the angiosperms. Some of these flowering plants bear structures that attract insects and other animals to spread pollen; other angiosperms are pollinated by wind or water. This innovation causes a major burst of animal coevolution. First freshwater pelomedusid turtles. Earliest krill. |- valign="TOP" | align="RIGHT" nowrap | 120 Ma | Oldest fossils of heterokonts, including both marine diatoms and silicoflagellates. |- valign="TOP" | align="RIGHT" nowrap | 115 Ma | First monotreme mammals. |- valign="TOP" | align="RIGHT" nowrap | 114 Ma | Earliest bees.<ref name="bees-argentina">{{cite web |last=Greshko |first=Michael |title=Oldest evidence of modern bees found in Argentina |url=https://www.nationalgeographic.com/science/article/oldest-ever-fossil-bee-nests-discovered-in-patagonia |archive-url=https://web.archive.org/web/20210223204426/https://www.nationalgeographic.com/science/article/oldest-ever-fossil-bee-nests-discovered-in-patagonia |archive-date=February 23, 2021 |website=National Geographic |access-date=2022-06-22 |quote=The model shows that modern bees started diversifying at a breakneck pace about 114 million years ago, right around the time that eudicots—the plant group that comprises 75 percent of flowering plants—started branching out. The results, which confirm some earlier genetic studies, strengthen the case that flowering plants and pollinating bees have coevolved from the very beginning. |date=2020-02-11}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 112 Ma |''Xiphactinus'', a large predatory fish, appears in the fossil record. |- valign="TOP" | align="RIGHT" nowrap | 110 Ma | First hesperornithes, toothed diving birds. Earliest limopsid, verticordiid, and thyasirid bivalves. |- valign="TOP" | align="RIGHT" nowrap="" | 100 Ma | First ants.<ref>{{Cite journal |last1=Moreau |first1=Corrie S. |last2=Bell |first2=Charles D. |last3=Vila |first3=Roger |last4=Archibald |first4=S. Bruce |last5=Pierce |first5=Naomi E. |date=2006-04-07 |title=Phylogeny of the Ants: Diversification in the Age of Angiosperms |url=https://www.science.org/doi/10.1126/science.1124891 |journal=Science |language=en |volume=312 |issue=5770 |pages=101–104 |doi=10.1126/science.1124891 |pmid=16601190 |bibcode=2006Sci...312..101M |s2cid=20729380 |issn=0036-8075|url-access=subscription }}</ref> |- valign="TOP" | align="RIGHT" nowrap="" | 100&ndash;95 Ma | ''Spinosaurus'' appears in the fossil record.<ref>{{Cite journal |date=2022-10-05 |title=Spinosaurus is not an aquatic dinosaur | journal=eLife |pmc=9711522 |language=en |last1=Sereno |first1=P. C. |last2=Myhrvold |first2=N. |last3=Henderson |first3=D. M. |last4=Fish |first4=F. E. |last5=Vidal |first5=D. |last6=Baumgart |first6=S. L. |last7=Keillor |first7=T. M. |last8=Formoso |first8=K. K. |last9=Conroy |first9=L. L. |volume=11 |article-number=e80092 |doi=10.7554/eLife.80092 |doi-access=free |pmid=36448670 }}</ref> |- valign="TOP" | align="RIGHT" nowrap="" | 95 Ma |First crocodilians evolve.<ref>{{Cite web |title=Mindat.org |url=https://www.mindat.org/taxon-704.html |access-date=2022-10-03 |website=www.mindat.org}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 90 Ma | Extinction of ichthyosaurs. Earliest snakes and nuculanid bivalves. Large diversification in angiosperms: magnoliids, rosids, hamamelidids, monocots, and ginger. Earliest examples of ticks. Probable origins of placental mammals (earliest undisputed fossil evidence is 66 Ma). |- |86&ndash;76 Ma |Diversification of therian mammals.<ref>{{Cite journal |last1=Grossnickle |first1=David M. |last2=Newham |first2=Elis |date=2016-06-15 |title=Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K–Pg boundary |journal=Proceedings of the Royal Society B: Biological Sciences |volume=283 |issue=1832 |article-number=20160256 |doi=10.1098/rspb.2016.0256 |pmc=4920311 |bibcode=2016PBioS.28360256G }}</ref><ref>{{Cite web |title=Mammals began their takeover long before the death of the dinosaurs |url=https://www.sciencedaily.com/releases/2016/06/160607220628.htm |access-date=2022-09-25 |website=ScienceDaily |language=en}}</ref> |- valign="TOP" | align="RIGHT" nowrap | 70 Ma | Multituberculate mammals increase in diversity. First yoldiid bivalves. First possible ungulates (''Protungulatum''). |- valign="TOP" | align="RIGHT" nowrap | 68&ndash;66 Ma | ''Tyrannosaurus'', the largest terrestrial predator of western North America, appears in the fossil record. First species of ''Triceratops.''<ref>{{Cite web |last=Finds |first=Study |date=2021-12-02 |title=T-rex fossil reveals dinosaur from 68 million years ago likely had a terrible toothache! |url=https://studyfinds.org/t-rex-fossil-toothache/ |access-date=2022-09-24 |website=Study Finds |language=en-US}}</ref> |}

==== Cenozoic Era ==== {{Main|Cenozoic}} [[File:Patriofelis-mount.jpg|thumb|right|240px|Mount of oxyaenid ''Patriofelis'' from the American Museum of Natural History ]] [[File:Icaronycteris index.jpg|thumb|right|240px|The bat ''Icaronycteris'' appeared 52.2 million years ago]] thumb|right|240px|Grass flowers [[File:1064376 - Megafauna - Museu Nacional de História Natural UFRJ - 22 Outubro 2010 - Rio de Janeiro - Brazil.jpg|thumb|240px|Reconstructed skeletons of flightless terror bird and ground sloth at the Museu Nacional, Rio de Janeiro]] [[File:Diprotodon optatum (2).jpg|thumb|240px|''Diprotodon'' went extinct about 40,000 years ago as part of the Quaternary extinction event, along with every other Australian creature over {{cvt|100|kg}}.]] [[File:Homo floresiensis v 2-0.jpg|thumb|240px|50,000 years ago several different human species coexisted on Earth including modern humans and ''Homo floresiensis'' (pictured).]] [[File:PantheraLeoAtrox1 (retouched).jpg|thumb|240px|American lions exceeded extant lions in size and ranged over much of North America until 11,000 BP.]] {{table alignment}} {| class="wikitable col1right" |+Cenozoic era (66 Ma &ndash; present) ! Date ! Event |- valign="TOP" |66 Ma |The Cretaceous–Paleogene extinction event eradicates about half of all animal species, including mosasaurs, pterosaurs, plesiosaurs, ammonites, belemnites, rudist and inoceramid bivalves, most planktic foraminifers, and all of the dinosaurs excluding the birds.<ref>{{cite journal |last1=Chiappe |first1=Luis M. |author-link1=Luis M. Chiappe |last2=Dyke |first2=Gareth J. |author-link2=Gareth J. Dyke |date=November 2002 |title=The Mesozoic Radiation of Birds |journal=Annual Review of Ecology and Systematics |volume=33 |issue=1 |pages=91–124 |doi=10.1146/annurev.ecolsys.33.010802.150517 |bibcode=2002AnRES..33...91C |issn=1545-2069 }}</ref> |- valign="TOP" |66 Ma | Rapid dominance of conifers and ginkgos in high latitudes, along with mammals becoming the dominant species. First psammobiid bivalves. Earliest rodents. Rapid diversification in ants. |- valign="TOP" |63 Ma | Evolution of the creodonts, an important group of meat-eating (carnivorous) mammals. |- |62 Ma |Evolution of the first penguins. |- valign="TOP" |60 Ma | Diversification of large, flightless birds. Earliest true primates,{{Who|date=January 2019}} along with the first semelid bivalves, edentate, carnivoran and lipotyphlan mammals, and owls. The ancestors of the carnivorous mammals (miacids) were alive.{{Citation needed|date=January 2019}} |- |59 Ma |Earliest sailfish appear. |- valign="TOP" |56 Ma | ''Gastornis'', a large flightless bird, appears in the fossil record. |- valign="TOP" |55 Ma | Modern bird groups diversify (first song birds, parrots, loons, swifts, woodpeckers), first whale (''Himalayacetus''), earliest lagomorphs, armadillos, appearance of sirenian, proboscidean mammals in the fossil record. Flowering plants continue to diversify. The ancestor (according to theory) of the species in the genus ''Carcharodon'', the early mako shark ''Isurus hastalis'', is alive. Ungulates split into artiodactyla and perissodactyla, with some members of the former returning to the sea. |- valign="TOP" |52 Ma | First bats appear (''Onychonycteris''). |- valign="TOP" |50 Ma | Peak diversity of dinoflagellates and nannofossils, increase in diversity of anomalodesmatan and heteroconch bivalves, brontotheres, tapirs, rhinoceroses, and camels appear in the fossil record, diversification of primates. |- valign="TOP" |40 Ma | Modern-type butterflies and moths appear. Extinction of ''Gastornis''. ''Basilosaurus'', one of the first of the giant whales, appeared in the fossil record. |- |38 Ma |Earliest bears. |- valign="TOP" |37 Ma | First nimravid ("false saber-toothed cats") carnivores — these species are unrelated to modern-type felines. First alligators and ruminants. |- valign="TOP" |35 Ma | Grasses diversify from among the monocot angiosperms; grasslands begin to expand. Slight increase in diversity of cold-tolerant ostracods and foraminifers, along with major extinctions of gastropods, reptiles, amphibians, and multituberculate mammals. Many modern mammal groups begin to appear: first glyptodonts, ground sloths, canids, peccaries, and the first eagles and hawks. Diversity in toothed and baleen whales. |- valign="TOP" |33 Ma | Evolution of the thylacinid marsupials (''Badjcinus''). |- valign="TOP" |30 Ma | First balanids and eucalypts, extinction of embrithopod and brontothere mammals, earliest pigs and cats. |- valign="TOP" |28 Ma | ''Paraceratherium'' appears in the fossil record, the largest terrestrial mammal that ever lived. First pelicans. |- valign="TOP" |25 Ma | ''Pelagornis sandersi'' appears in the fossil record, the largest flying bird that ever lived. |- valign="TOP" |25 Ma | First deer. |- |24 Ma |First pinnipeds. |- |23 Ma |Earliest ostriches, trees representative of most major groups of oaks have appeared by now.<ref>{{Cite web|url=http://www.oaksofchevithornebarton.com/about-history-of-garden.cfm?|title=About > The Origins of Oaks|website=www.oaksofchevithornebarton.com|access-date=2019-09-28}}</ref> |- valign="TOP" |20 Ma | First giraffes, hyenas, and giant anteaters, increase in bird diversity. |- |17 Ma |First birds of the genus Corvus (crows). |- valign="TOP" |15 Ma | Genus ''Mammut'' appears in the fossil record, first bovids and kangaroos, diversity in Australian megafauna. |- valign="TOP" |10 Ma | Grasslands and savannas are established, diversity in insects, especially ants and termites, horses increase in body size and develop high-crowned teeth, major diversification in grassland mammals and snakes. |- valign="TOP" |9.5 Ma<br />{{Dubious |Great American Interchange|reason=Date is too early; it should be more like 2.7 mya|date=March 2020}} |Great American Interchange, where various land and freshwater faunas migrated between North and South America. Armadillos, opossums, hummingbirds Phorusrhacids, Ground Sloths, Glyptodonts, and Meridiungulates traveled to North America, while horses, tapirs, saber-toothed cats, jaguars, bears, coaties, ferrets, otters, skunks and deer entered South America. |- |9 Ma |First platypuses. |- valign="TOP" |6.5 Ma | First hominins (''Sahelanthropus''). |- valign="TOP" |6 Ma | Australopithecines diversify (''Orrorin'', ''Ardipithecus''). |- valign="TOP" |5 Ma | First tree sloths and hippopotami, diversification of grazing herbivores like zebras and elephants, large carnivorous mammals like lions and the genus ''Canis'', burrowing rodents, kangaroos, birds, and small carnivores, vultures increase in size, decrease in the number of perissodactyl mammals. Extinction of nimravid carnivores. First leopard seals. |- valign="TOP" |4.8 Ma | Mammoths appear in the fossil record. |- |4.5 Ma |Marine iguanas diverge from land iguanas. |- valign="TOP" |4 Ma | ''Australopithecus'' evolves. ''Stupendemys'' appears in the fossil record as the largest freshwater turtle, first modern elephants, giraffes, zebras, lions, rhinoceros and gazelles appear in the fossil record |- |3.6 Ma |Blue whales grow to modern size. |- |3 Ma |Earliest swordfish. |- valign="TOP" |2.7 Ma | ''Paranthropus evolves.'' |- valign="TOP" |2.5 Ma | Earliest species of ''Arctodus'' and ''Smilodon'' evolve. |- valign="TOP" |2 Ma | First members of genus ''Homo'', Homo Habilis, appear in the fossil record. Diversification of conifers in high latitudes. The eventual ancestor of cattle, aurochs (''Bos primigenus''), evolves in India. |- valign="TOP" |1.7 Ma | Australopithecines go extinct. |- valign="TOP" |1.2 Ma | Evolution of ''Homo antecessor''. The last members of ''Paranthropus'' die out. |- |1.0 Ma |First coyotes. |- valign="TOP" |810 ka |First wolves |- valign="TOP" |- |600 ka | Evolution of ''Homo heidelbergensis.'' |- |400 ka |First polar bears. |- valign="TOP" |350 ka | Evolution of Neanderthals. |- valign="TOP" |300 ka | ''Gigantopithecus'', a giant relative of the orangutan from Asia dies out. |- valign="TOP" |250 ka | Anatomically modern humans appear in Africa.<ref>{{cite journal |last1=Karmin |first1=Monika |last2=Saag |first2=Lauri |last3=Vicente |first3=Mário |date=April 2015 |title=A recent bottleneck of Y chromosome diversity coincides with a global change in culture |journal=Genome Research |volume=25 |issue=4 |pages=459–466 |doi=10.1101/gr.186684.114 |issn=1088-9051 |name-list-style=vanc|display-authors=etal |pmid=25770088 |pmc=4381518}}</ref><ref>{{cite press release |last1=Brown |first1=Frank |last2=Fleagle |first2=John |author-link2=John G. Fleagle |last3=McDougall |first3=Ian |author-link3=Ian McDougall (geologist) |date=February 16, 2005 |title=The Oldest Homo sapiens |url=http://unews.utah.edu/news_releases/the-oldest-homo-sapiens/ |location=Salt Lake City, UT |publisher=University of Utah |access-date=2015-03-10 |archive-date=2015-08-02 |archive-url=https://web.archive.org/web/20150802010634/http://unews.utah.edu/news_releases/the-oldest-homo-sapiens/ }}</ref><ref>{{cite journal |last1=Alemseged |first1=Zeresenay |author-link1=Zeresenay Alemseged |last2=Coppens |first2=Yves |author-link2=Yves Coppens |last3=Geraads |first3=Denis |date=February 2002 |title=Hominid cranium from Homo: Description and taxonomy of Homo-323-1976-896 |journal=American Journal of Physical Anthropology |volume=117 |issue=2 |pages=103–112 |doi=10.1002/ajpa.10032 |issn=0002-9483 |pmid=11815945 |url=http://doc.rero.ch/record/13324/files/PAL_E59.pdf }}</ref> Around 50 ka they start colonising the other continents, replacing Neanderthals in Europe and other hominins in Asia. |- valign="TOP" |70 ka | Genetic bottleneck in humans (Toba catastrophe theory). |- valign="TOP" |40 ka | Last giant monitor lizards (Varanus priscus) die out. |- valign="TOP" |35–25 ka | Extinction of Neanderthals. Domestication of dogs. |- valign="TOP" |15 ka | Last woolly rhinoceros (''Coelodonta antiquitatis'') are believed to have gone extinct. |- valign="TOP" |11 ka | Short-faced bears vanish from North America, with the last giant ground sloths dying out. All Equidae become extinct in North America. Domestication of various ungulates. |- valign="TOP" |10 ka | Holocene epoch starts<ref>{{cite web |url=http://www.stratigraphy.org/ICSchart/ChronostratChart2014-10.jpg |title=International Stratigraphic Chart (v 2014/10) |publisher=International Commission on Stratigraphy |location=Beijing, China |format=PDF |access-date=2015-03-11}}</ref> after the Last Glacial Maximum. Last mainland species of woolly mammoth (''Mammuthus primigenus'') die out, as does the last ''Smilodon'' species. |- valign="TOP" | 1 ka | The giant lemur dies out. |}

== See also == {{Div col}} * Evolutionary history of plants (timeline) * Geologic time scale * History of Earth * Sociocultural evolution * Timeline of human evolution {{div col end}}

== References == {{Reflist}}

=== Bibliography === {{Refbegin}} * {{cite book |last1=Barton |first1=Nicholas H. |author-link1=Nick Barton |last2=Briggs |first2=Derek E.G. |author-link2=Derek Briggs |last3=Eisen |first3=Jonathan A. |author-link3=Jonathan Eisen |last4=Goldstein |author-link4=David B. Goldstein (geneticist) |first4=David B. |last5=Patel |first5=Nipam H. |year=2007 |title=Evolution |location=Cold Spring Harbor, NY |publisher=Cold Spring Harbor Laboratory Press |isbn=978-0-87969-684-9 |lccn=2007010767 |oclc=86090399 }} * {{cite book |last1=Bernstein |first1=Harris |last2=Bernstein |first2=Carol |last3=Michod |first3=Richard E. |year=2012 |chapter=DNA Repair as the Primary Adaptive Function of Sex in Bacteria and Eukaryotes |chapter-url=https://www.novapublishers.com/catalog/product_info.php?products_id=31918 |editor1-last=Kimura |editor1-first=Sakura |editor2-last=Shimizu |editor2-first=Sora |title=DNA Repair: New Research |location=Hauppauge, NY |publisher=Nova Science Publishers |isbn=978-1-62100-808-8 |lccn=2011038504 |oclc=828424701 }} * {{cite book |last=Bjornerud |first=Marcia |year=2005 |title=Reading the Rocks: The Autobiography of the Earth |url=https://archive.org/details/readingrocksauto00bjor |url-access=registration |location=Cambridge, MA |publisher=Westview Press |isbn=978-0-8133-42498 |lccn=2004022738 |oclc=56672295 }} * {{cite book |last=Kirschvink |first=Joseph L. |year=1992 |chapter=Late Proterozoic Low-Latitude Global Glaciation: the Snowball Earth |chapter-url=http://web.gps.caltech.edu/~jkirschvink/pdfs/firstsnowball.pdf |editor1-last=Schopf |editor1-first=J. William |editor1-link=J. William Schopf |editor2-last=Klein |editor2-first=Cornelis |title=The Proterozoic Biosphere: A Multidisciplinary Study |location=Cambridge; New York |publisher=Cambridge University Press |isbn=978-0-521-36615-1 |lccn=91015085 |oclc=23583672 }} * {{cite book |last=McKinney |first=Michael L. |year=1997 |chapter=How do rare species avoid extinction? A paleontological view |editor1-last=Kunin |editor1-first=William E. |editor2-last=Gaston |editor2-first=Kevin J. |title=The Biology of Rarity: Causes and consequences of rare—common differences |edition=1st |location=London; New York |publisher=Chapman & Hall |isbn=978-0-412-63380-5 |lccn=96071014 |oclc=36442106 }} * {{cite book |last1=Miller |first1=G. Tyler |last2=Spoolman |first2=Scott E. |year=2012 |title=Environmental Science |edition=14th |location=Belmont, CA |publisher=Brooks/Cole |isbn=978-1-111-98893-7 |lccn=2011934330 |oclc=741539226 }} * {{cite book |last1=Stearns |first1=Beverly Peterson |last2=Stearns |first2=Stephen C. |author-link2=Stephen C. Stearns |year=1999 |title=Watching, from the Edge of Extinction |url=https://archive.org/details/isbn_9780300084696 |url-access=registration |location=New Haven, CT |publisher=Yale University Press |isbn=978-0-300-07606-6 |lccn=98034087 |oclc=47011675 }} {{Refend}}

== Further reading == * {{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |year=2004 |title=The Ancestor's Tale: A Pilgrimage to the Dawn of Life |location=Boston |publisher=Houghton Mifflin Company |isbn=978-0-618-00583-3 |lccn=2004059864 |oclc=56617123 |title-link=The Ancestor's Tale }}

== External links == * {{cite web |url=http://evolution.berkeley.edu/ |title=Understanding Evolution: your one-stop resource for information on evolution |publisher=University of California, Berkeley |access-date=2015-03-18}} * {{cite web |url=http://tolweb.org/Life_on_Earth/1 |title=Life on Earth |date=January 1, 1997 |website=Tree of Life Web Project |publisher=University of Arizona |access-date=2015-03-18}} Explore complete phylogenetic tree interactively * {{cite web |url=http://www.talkorigins.org/origins/geo_timeline.html |title=Evolutionary and Geological Timelines |last=Brandt |first=Niel |author-link=Niel Brandt |website=TalkOrigins Archive |publisher=The TalkOrigins Foundation, Inc. |location=Houston, TX |access-date=2015-03-18}} * {{cite web |url=http://www.palaeos.com |title=Palaeos: Life Through Deep Time |website=Palaeos |access-date=2015-03-18}} * {{cite web |url=http://www.johnkyrk.com/evolution.html |title=Evolution |last=Kyrk |first=John |website=Cell Biology Animation |format=SWF |access-date=2015-03-18 |archive-date=2012-10-22 |archive-url=https://web.archive.org/web/20121022084620/http://johnkyrk.com/evolution.html }} Interactive timeline from Big Bang to present * {{cite web |url=http://sci.waikato.ac.nz/evolution/plantEvolution.shtml |title=Plant Evolution |website=Plant and Animal Evolution |publisher=University of Waikato |access-date=2015-03-18 |archive-date=2012-07-28 |archive-url=https://web.archive.org/web/20120728225355/http://sci.waikato.ac.nz/evolution/plantEvolution.shtml }} Sequence of Plant Evolution * {{cite web |url=http://sci.waikato.ac.nz/evolution/AnimalEvolution.shtml |title=The History of Animal Evolution |website=Plant and Animal Evolution |publisher=University of Waikato |access-date=2015-03-18 |archive-date=2016-06-27 |archive-url=https://web.archive.org/web/20160627175302/http://sci.waikato.ac.nz/evolution/AnimalEvolution.shtml }} Sequence of Animal Evolution * {{cite web |url=http://draget.net/hoe/index.php |title=History of Life on Earth |last1=Yeo |first1=Dannel |last2=Drage |first2=Thomas |year=2006 |access-date=2015-03-19 |archive-url=https://web.archive.org/web/20150315040156/http://draget.net/hoe/index.php |archive-date=2015-03-15 }} * {{cite AV media |year=2007 |title=Exploring Time |url=http://exploringtime.org/?page=segments |access-date=2015-03-19 |publisher=The Science Channel}} * {{cite web |url=http://www.plantsci.cam.ac.uk/timeline/ |title=Plant evolution timeline |last=Roberts |first=Ben |publisher=University of Cambridge |access-date=2015-03-19 |archive-url=https://web.archive.org/web/20150313180118/http://www.plantsci.cam.ac.uk/timeline |archive-date=2015-03-13 }} * [http://www.naturelyrics.com/pages/articles/nature_photography/nature_in_nature_photography.html Art of the Nature Timelines on Wikipedia] {{Evolution}} {{Earth}} {{Portal bar|Evolutionary biology|Paleontology}}

{{DEFAULTSORT:Timeline Of Evolution}} Category:Evolution-related timelines Category:Origin of life evolution