Earliest known life forms - wikipedia Earliest known life forms For the origin of life, see Abiogenesis, Astrobiology, and Panspermia. This article is about a thing that is living or alive. For other uses, see Lifeform ( disambiguation ). For longest lifespans, see List of longest - living organisms. Life timeline view discuss edit - 4500 -- -- - 4000 -- -- - 3500 -- -- - 3000 -- -- - 2500 -- -- - 2000 -- -- - 1500 -- -- - 1000 -- -- - 500 -- -- 0 -- water Single - celled life photosynthesis Eukaryotes Multicellular life Land life Dinosaurs Mammals Flowers ← Earliest Earth ( − 4540 ) ← Earliest water ← Earliest life ← LHB meteorites ← Earliest oxygen ← Atmospheric oxygen ← Oxygen crisis ← Earliest sexual reproduction ← Ediacara biota ← Cambrian explosion ← Earliest humans h n r o z o i r o r o z o i r h n d n Pongola Huronian Cryogenian Andean Karoo Quaternary Axis scale : millions of years ago. Orange labels : ice ages. Also see : Human timeline and Nature timeline The earliest known life forms on Earth are putative fossilized microorganisms found in hydrothermal vent precipitates. The earliest time that life forms first appeared on Earth is unknown. They may have lived earlier than 3.77 billion years ago, possibly as early as 4.28 billion years ago, not long after the oceans formed 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Contents 1 Overview 2 Earliest life forms 3 Gallery 4 See also 5 References 6 External links Overview A life form, or lifeform, is an entity or being that is living. Earth remains the only place in the universe known to harbor life forms. More than 99 % of all species of life forms, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Example of archaea, prokaroytic microbes, first found in extreme environments, such as volcanic hot springs. Some estimates on the number of Earth 's current species of life forms range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. However, a May 2016 scientific report estimates that 1 trillion species are currently on Earth, with only one - thousandth of one percent described. The total number of DNA base pairs on Earth is estimated at 5.0 x 10 with a weight of 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC ( trillion tons of carbon ). In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor ( LUCA ) of all organisms living on Earth. The Earth 's biosphere includes soil, hot springs, rock up to 19 km ( 12 mi ) or deeper underground, the deepest parts of the ocean, and at least 64 km ( 40 mi ) high into the atmosphere. Under certain test conditions, life forms have been observed to thrive in the near - weightlessness of space and to survive in the vacuum of outer space. Life forms appear to thrive in the Mariana Trench, the deepest spot in the Earth 's oceans. Other researchers reported related studies that life forms thrive inside rocks up to 580 m ( 1,900 ft ; 0.36 mi ) below the sea floor under 2,590 m ( 8,500 ft ; 1.61 mi ) of ocean off the coast of the northwestern United States, as well as 2,400 m ( 7,900 ft ; 1.5 mi ) beneath the seabed off Japan. In August 2014, scientists confirmed the existence of life forms living 800 m ( 2,600 ft ; 0.50 mi ) below the ice of Antarctica. According to one researcher, `` You can find microbes everywhere -- they 're extremely adaptable to conditions, and survive wherever they are. '' Earliest life forms Evidence of possibly the oldest forms of life on Earth have been found in hydrothermal vent precipitates. Fossil evidence informs most studies of the origin of life. The age of the Earth is about 4.54 billion years ; the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. There is evidence that life began much earlier. In 2017, fossilized microorganisms, or microfossils, were announced to have been discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that may be as old as 4.28 billion years old, the oldest record of life on Earth, suggesting `` an almost instantaneous emergence of life '' after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Geyserite basin at Chinese Spring, Upper Geyser Basin, Yellowstone. `` Remains of life '' have been found in 4.1 billion - year - old rocks in Western Australia. Evidence of biogenic graphite, and possibly stromatolites, was discovered in 3.7 billion - year - old metasedimentary rocks in southwestern Greenland. In May 2017, evidence of life on land may have been found in 3.48 billion - year - old geyserite which is often found around hot springs and geysers, and other related mineral deposits, uncovered in the Pilbara Craton of Western Australia. This complements the November 2013 publication that microbial mat fossils had been found in 3.48 billion - year - old sandstone in Western Australia. According to biologist Stephen Blair Hedges, `` If life arose relatively quickly on Earth... then it could be common in the universe. '' Gallery Stromatolites are made by microbes moving upward to avoid being smothered by sediment. Stromatolites left behind by cyanobacteria are one of the oldest fossils of life on Earth. The cyanobacterial - algal mat, salty lake on the White Sea seaside. Wrinkled Kinneyia - type sedimentary structures formed beneath cohesive microbial mats in peritidal zones. Kinneyia - like structure in the Grimsby Formation ( Silurian ) exposed in Niagara Gorge, NY. Life on Earth 0.2 Mya Humans 140 Mya Flowers 200 Mya Mammals 300 Mya Dinosaurs 3500 Mya Oxygen 4280 Mya Microorganisms 4410 Mya Water 4540 Mya Earth See also Astrobiology Extraterrestrial life Extremophile Geyserite Hypothetical types of biochemistry Human timeline Life List of life forms List of longest - living organisms Last universal common ancestor Nature timeline Oldest dated rocks Organism Outline of biology Panspermia Terminology of biology Timeline of the evolutionary history of life Zircon References ^ Jump up to : Dodd, Matthew S. ; Papineau, Dominic ; Grenne, Tor ; Slack, John F. ; Rittner, Martin ; Pirajno, Franco ; O'Neil, Jonathan ; Little, Crispin T.S. ( 1 March 2017 ). `` Evidence for early life in Earth 's oldest hydrothermal vent precipitates ''. Nature. 543 : 60 -- 64. doi : 10.1038 / nature21377. Retrieved 2 March 2017. ^ Jump up to : Zimmer, Carl ( 1 March 2017 ). `` Scientists Say Canadian Bacteria Fossils May Be Earth 's Oldest ''. New York Times. Retrieved 2 March 2017. ^ Jump up to : Ghosh, Pallab ( 1 March 2017 ). `` Earliest evidence of life on Earth ' found ''. BBC News. Retrieved 2 March 2017. ^ Jump up to : Dunham, Will ( 1 March 2017 ). `` Canadian bacteria - like fossils called oldest evidence of life ''. Reuters. Retrieved 1 March 2017. Jump up ^ `` life form ''. World English Dictionary. Dictionary.com. 2009. Jump up ^ `` life form ''. Online Oxford Dictionary of English. Oxford University Press. 2005. Jump up ^ Graham, Robert W. ( February 1990 ). `` Extraterrestrial Life in the Universe '' ( PDF ) ( NASA Technical Memorandum 102363 ). Lewis Research Center, Cleveland, Ohio : NASA. Retrieved 2 June 2015. Jump up ^ Altermann, Wladyslaw ( 2009 ). `` From Fossils to Astrobiology -- A Roadmap to Fata Morgana ? '' ( PDF ). In Seckbach, Joseph ; Walsh, Maud. From Fossils to Astrobiology : Records of Life on Earth and the Search for Extraterrestrial Biosignatures. Cellular Origin, Life in Extreme Habitats and Astrobiology. 12. Dordrecht, the Netherlands ; London : Springer Science + Business Media. p. xvii. ISBN 978 - 1 - 4020 - 8836 - 0. LCCN 2008933212. Retrieved 5 June 2015. Jump up ^ Kunin, W.E. ; Gaston, Kevin, eds. ( 31 December 1996 ). The Biology of Rarity : Causes and consequences of rare -- common differences. ISBN 978 - 0412633805. Retrieved 26 May 2015. Jump up ^ Stearns, Beverly Peterson ; Stearns, S.C. ; Stearns, Stephen C. ( 2000 ). Watching, from the Edge of Extinction. Yale University Press. p. preface x. ISBN 978 - 0 - 300 - 08469 - 6. Retrieved 30 May 2017. Jump up ^ Novacek, Michael J. ( 8 November 2014 ). `` Prehistory 's Brilliant Future ''. New York Times. Retrieved 25 December 2014. Jump up ^ G. Miller ; Scott Spoolman ( 2012 ). Environmental Science - Biodiversity Is a Crucial Part of the Earth 's Natural Capital. Cengage Learning. p. 62. ISBN 1 - 133 - 70787 - 4. Retrieved 27 December 2014. Jump up ^ Mora, C. ; Tittensor, D.P. ; Adl, S. ; Simpson, A.G. ; Worm, B. ( 23 August 2011 ). `` How many species are there on Earth and in the ocean ? ''. PLOS Biology. 9 : e1001127. doi : 10.1371 / journal. pbio. 1001127. PMC 3160336. PMID 21886479. Jump up ^ Staff ( 2 May 2016 ). `` Researchers find that Earth may be home to 1 trillion species ''. National Science Foundation. Retrieved 6 May 2016. Jump up ^ Nuwer, Rachel ( 18 July 2015 ). `` Counting All the DNA on Earth ''. The New York Times. New York : The New York Times Company. ISSN 0362 - 4331. Retrieved 18 July 2015. Jump up ^ `` The Biosphere : Diversity of Life ''. Aspen Global Change Institute. Basalt, CO. Retrieved 19 July 2015. Jump up ^ Wade, Nicholas ( 25 July 2016 ). `` Meet Luca, the Ancestor of All Living Things ''. New York Times. Retrieved 25 July 2016. Jump up ^ University of Georgia ( 25 August 1998 ). `` First - Ever Scientific Estimate Of Total Bacteria On Earth Shows Far Greater Numbers Than Ever Known Before ''. Science Daily. Retrieved 10 November 2014. Jump up ^ Hadhazy, Adam ( 12 January 2015 ). `` Life Might Thrive a Dozen Miles Beneath Earth 's Surface ''. Astrobiology Magazine. Retrieved 11 March 2017. Jump up ^ Fox - Skelly, Jasmin ( 24 November 2015 ). `` The Strange Beasts That Live In Solid Rock Deep Underground ''. BBC online. Retrieved 11 March 2017. Jump up ^ Dvorsky, George ( 13 September 2017 ). `` Alarming Study Indicates Why Certain Bacteria Are More Resistant to Drugs in Space ''. Gizmodo. Retrieved 14 September 2017. Jump up ^ Caspermeyer, Joe ( 23 September 2007 ). `` Space flight shown to alter ability of bacteria to cause disease ''. Arizona State University. Retrieved 14 September 2017. Jump up ^ Dose, K. ; Bieger - Dose, A. ; Dillmann, R. ; Gill, M. ; Kerz, O. ; Klein, A. ; Meinert, H. ; Nawroth, T. ; Risi, S. ; Stridde, C. ( 1995 ). `` ERA - experiment `` space biochemistry '' ``. Advances in Space Research. 16 ( 8 ) : 119 -- 129. doi : 10.1016 / 0273 - 1177 ( 95 ) 00280 - R. PMID 11542696. Jump up ^ Vaisberg, Horneck G. ; Eschweiler, U. ; Reitz, G. ; Wehner, J. ; Willimek, R. ; Strauch, K. ( 1995 ). `` Biological responses to space : results of the experiment `` Exobiological Unit '' of ERA on EURECA I ``. Adv Space Res. 16 ( 8 ) : 105 -- 18. Bibcode : 1995AdSpR... 16... 105V. doi : 10.1016 / 0273 - 1177 ( 95 ) 00279 - N. PMID 11542695. ^ Jump up to : Choi, Charles Q. ( 17 March 2013 ). `` Microbes Thrive in Deepest Spot on Earth ''. LiveScience. Retrieved 17 March 2013. Jump up ^ Glud, Ronnie ; Wenzhöfer, Frank ; Middelboe, Mathias ; Oguri, Kazumasa ; Turnewitsch, Robert ; Canfield, Donald E. ; Kitazato, Hiroshi ( 17 March 2013 ). `` High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth ''. Nature Geoscience. 6 ( 4 ) : 284 -- 288. Bibcode : 2013NatGe... 6... 284G. doi : 10.1038 / ngeo1773. Retrieved 17 March 2013. Jump up ^ Oskin, Becky ( 14 March 2013 ). `` Intraterrestrials : Life Thrives in Ocean Floor ''. LiveScience. Retrieved 17 March 2013. Jump up ^ Morelle, Rebecca ( 15 December 2014 ). `` Microbes discovered by deepest marine drill analysed ''. BBC News. Retrieved 15 December 2014. Jump up ^ Fox, Douglas ( 20 August 2014 ). `` Lakes under the ice : Antarctica 's secret garden ''. Nature. 512 ( 7514 ) : 244 -- 246. Bibcode : 2014Natur. 512... 244F. doi : 10.1038 / 512244a. Retrieved 21 August 2014. Jump up ^ Mack, Eric ( 20 August 2014 ). `` Life Confirmed Under Antarctic Ice ; Is Space Next ? ''. Forbes. Retrieved 21 August 2014. Jump up ^ `` Age of the Earth ''. United States Geological Survey. 9 July 2007. Retrieved 2006 - 01 - 10. Jump up ^ Dalrymple, G. Brent ( 2001 ). `` The age of the Earth in the twentieth century : a problem ( mostly ) solved ''. Special Publications, Geological Society of London. 190 ( 1 ) : 205 -- 221. Bibcode : 2001GSLSP. 190... 205D. doi : 10.1144 / GSL. SP. 2001.190. 01.14. Jump up ^ Manhesa, Gérard ; Allègre, Claude J. ; Dupréa, Bernard ; Hamelin, Bruno ( May 1980 ). `` Lead isotope study of basic - ultrabasic layered complexes : Speculations about the age of the earth and primitive mantle characteristics ''. Earth and Planetary Science Letters. Amsterdam, the Netherlands : Elsevier. 47 ( 3 ) : 370 -- 382. Bibcode : 1980E&PSL... 47... 370M. doi : 10.1016 / 0012 - 821X ( 80 ) 90024 - 2. ISSN 0012 - 821X. Jump up ^ Schopf, J. William ; Kudryavtsev, Anatoliy B. ; Czaja, Andrew D. ; Tripathi, Abhishek B. ( 5 October 2007 ). `` Evidence of Archean life : Stromatolites and microfossils ''. Precambrian Research. Amsterdam, the Netherlands : Elsevier. 158 ( 3 -- 4 ) : 141 -- 155. doi : 10.1016 / j. precamres. 2007.04. 009. ISSN 0301 - 9268. Jump up ^ Schopf, J. William ( 29 June 2006 ). `` Fossil evidence of Archaean life ''. Philosophical Transactions of the Royal Society B. London : Royal Society. 361 ( 1470 ) : 869 -- 885. doi : 10.1098 / rstb. 2006.1834. ISSN 0962 - 8436. PMC 1578735. PMID 16754604. Jump up ^ Raven, Peter H. ; Johnson, George B. ( 2002 ). Biology ( 6th ed. ). Boston, MA : McGraw - Hill. p. 68. ISBN 0 - 07 - 112261 - 3. LCCN 2001030052. OCLC 45806501. ^ Jump up to : Staff ( 9 May 2017 ). `` Oldest evidence of life on land found in 3.48 - billion - year - old Australian rocks ''. Phys.org. Retrieved 13 May 2017. ^ Jump up to : Djokic, Tara ; Van Kranendonk, Martin J. ; Campbell, Kathleen A. ; Walter, Malcolm R. ; Ward, Colin R. ( 9 May 2017 ). `` Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits ''. Nature Communications. doi : 10.1038 / ncomms15263. Retrieved 13 May 2017. ^ Jump up to : Borenstein, Seth ( 19 October 2015 ). `` Hints of life on what was thought to be desolate early Earth ''. Excite. Yonkers, NY : Mindspark Interactive Network. Associated Press. Retrieved 20 October 2015. Jump up ^ Ohtomo, Yoko ; Kakegawa, Takeshi ; Ishida, Akizumi ; et al. ( January 2014 ). `` Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks ''. Nature Geoscience. London : Nature Publishing Group. 7 ( 1 ) : 25 -- 28. Bibcode : 2014NatGe... 7... 25O. doi : 10.1038 / ngeo2025. ISSN 1752 - 0894. Jump up ^ Wade, Nicholas ( 31 August 2016 ). `` World 's Oldest Fossils Found in Greenland ''. New York Times. Retrieved 31 August 2016. Jump up ^ Borenstein, Seth ( 13 November 2013 ). `` Oldest fossil found : Meet your microbial mom ''. Excite. Yonkers, NY : Mindspark Interactive Network. Associated Press. Retrieved 2 June 2015. Jump up ^ Pearlman, Jonathan ( 13 November 2013 ). `` ' Oldest signs of life on Earth found ' ''. The Daily Telegraph. London : Telegraph Media Group. Retrieved 2014 - 12 - 15. Jump up ^ Noffke, Nora ; Christian, Daniel ; Wacey, David ; Hazen, Robert M. ( 16 November 2013 ). `` Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion - Year - Old Dresser Formation, Pilbara, Western Australia ''. Astrobiology. New Rochelle, NY : Mary Ann Liebert, Inc. 13 ( 12 ) : 1103 -- 1124. Bibcode : 2013AsBio... 13.1103 N. doi : 10.1089 / ast. 2013.1030. ISSN 1531 - 1074. PMC 3870916. PMID 24205812. Jump up ^ Johnston, Ian ( 2 October 2017 ). `` Life first emerged in ' warm little ponds ' almost as old as the Earth itself - Charles Darwin 's famous idea backed by new scientific study ''. The Independent. Retrieved 2 October 2017. Jump up ^ Porada H. ; Ghergut J. ; Bouougri El H. ( 2008 ). `` Kinneyia - Type Wrinkle Structures -- Critical Review And Model Of Formation ''. PALAIOS. 23 ( 2 ) : 65 -- 77. doi : 10.2110 / palo. 2006. p06 - 095r. External links Biota ( Taxonomicon ) Life ( Systema Naturae 2000 ) Vitae ( BioLib ) Wikispecies -- a free directory of life Biology Subdisciplines Anatomy Astrobiology Biochemistry Biogeography Biological classification Biomechanics Biophysics Bioinformatics Biostatistics Botany Cell biology Cellular microbiology Chemical biology Chronobiology Cognitive biology Computational biology Conservation biology Developmental biology Ecology Epidemiology Epigenetics Evolutionary biology Evolutionary developmental biology Feminist biology Genetics Genomics Histology Human biology Immunology Lipidology Marine biology Mathematical biology Microbiology Molecular biology Mycology Nanobiotechnology Neuroscience Nutrition Origin of life Paleontology Parasitology Pathology Pharmacology Physiology Quantum biology Reproductive biology Structural biology Systematics Systems biology Toxicology Virology Virophysics Zoology Hierarchy of life Biosphere > Ecosystem > Community ( Biocoenosis ) > Population > Organism > Organ system > Organ > Tissue > Cell > Organelle > Biomolecular complex > Molecule ( Macromolecule, Biomolecule ) > Atom Foundations Cell theory Ecology Energy Transformation Evolution Genetics Homeostasis Synthetic biology Taxonomy Principles Evolution Adaptation Earliest known life forms Function Genetic drift Gene flow Macroevolution Microevolution Mutation Natural selection Speciation Ecology Biodiversity Biological interaction Community Ecosystem Habitat Niche Population dynamics Resources Molecular biology Cell signaling Development Epigenetics Gene regulation Meiosis Mitosis Post-transcriptional modification Biochemistry Carbohydrates Lipids Metabolism Nucleic acids Photosynthesis Proteins Glossaries Botanical terms Ecological terms Plant morphology terms Category Commons Portal WikiProject Origin of life Concepts Abiogenesis Common descent Earliest known life forms Last universal ancestor Protocell Quasispecies model Research Astrobiology Evolutionary biology Miller -- Urey experiment Paleobiology Hypotheses Clay hypothesis Iron -- sulfur world PAH world Panspermia Cosmic ancestry Peptide - RNA world Primordial soup RNA world Astrobiology Disciplines Astrochemistry Astrophysics Biochemistry Evolutionary biology Exoplanetology Microbiology Paleontology Planetary science Topics Allan Hills 84001 Biomolecule Biosignature Circumstellar habitable zone Drake equation Earliest known life forms Earth analog Extraterrestrial life Extremophiles Hypothetical types of biochemistry List of microorganisms tested in outer space List of potentially habitable exoplanets Molecules detected in outer space Natural satellite habitability Ocean planet Origin of life Panspermia Planetary habitability Search for extraterrestrial intelligence ( SETI ) Yamato meteorite Space missions Earth orbit Biolab Bion BIOPAN Biosatellite program ERA EXOSTACK EXPOSE O / OREOS OREOcube Tanpopo VEGGIE Mars missions Beagle 2 ExoMars ExoMars Trace Gas Orbiter Schiaparelli EDM lander Fobos - Grunt Mars Science Laboratory Phoenix Viking Planned BioSentinel Europa Clipper ExoMars ExoMars rover ExoMars 2020 surface platform Mars 2020 Mars Global Remote Sensing Orbiter and Small Rover Proposed Biological Oxidant and Life Detection Enceladus Explorer Enceladus Life Finder ‎ Enceladus Life Signatures and Habitability Europa Lander ExoLance Explorer of Enceladus and Titan Icebreaker Life Journey to Enceladus and Titan Laplace - P Life Investigation For Enceladus Mars sample return mission Northern Light Oceanus THEO Cancelled Astrobiology Field Laboratory Beagle 3 Living Interplanetary Flight Experiment Mars Astrobiology Explorer - Cacher Red Dragon Terrestrial Planet Finder Institutions and programs Astrobiology Society of Britain Astrobiology Science and Technology for Exploring Planets Breakthrough Initiatives Breakthrough Listen Breakthrough Message Carl Sagan Institute NASA Astrobiology Institute Nexus for Exoplanet System Science Ocean Worlds Exploration Program Category Portal Extraterrestrial life Events and objects ALH84001 Cells in the stratosphere CI1 fossils Murchison meteorite Nakhla meteorite Polonnaruwa meteorite Red rain in Kerala Shergotty meteorite Viking lander biological experiments Yamato 000593 Possible signals CP 1919 ( misidentified pulsar ) CTA - 102 ( misidentified quasar ) Fast radio burst ( unknown origin ) Wow ! signal ( inconclusive ) KIC 8462852 ( unusual light fluctuations ) SHGb02 + 14a ( radio source ) HD 164595 signal ( strong radio signal ) Life in the Universe Earliest known life forms Life on Enceladus Life on Europa Life on Mars Life on Titan Life on Venus Planetary habitability Catalog of Nearby Habitable Systems Circumstellar habitable zone Earth analog Extraterrestrial liquid water Galactic habitable zone Habitability of binary star systems Habitability of orange dwarf systems Habitability of red dwarf systems Natural satellite habitability Planetary habitability Space missions Beagle 2 Biological Oxidant and Life Detection BioSentinel Curiosity Darwin Enceladus Explorer Enceladus Life Finder Europa Clipper ExoMars ExoLance EXPOSE Foton - M3 Icebreaker Life Journey to Enceladus and Titan Laplace - P Life Investigation For Enceladus Living Interplanetary Flight Experiment Mars Geyser Hopper Mars sample return mission Mars 2020 Northern Light Opportunity SpaceX Red Dragon Spirit Tanpopo Titan Mare Explorer Venus In Situ Explorer Viking 1 Viking 2 Interstellar communication Active SETI Allen Telescope Array Arecibo message Arecibo Observatory Bracewell probe Breakthrough Initiatives Breakthrough Listen Breakthrough Message Communication with extraterrestrial intelligence Gauss 's Pythagorean right triangle proposal Lincos language Pioneer plaque Project Cyclops Project Ozma Project Phoenix SERENDIP Search for extraterrestrial intelligence SETI@home setiQuest Voyager Golden Record Water hole Xenolinguistics Exhibitions The Science of Aliens Hypotheses Ancient astronauts Aurelia and Blue Moon Cosmic pluralism Directed panspermia Drake equation Extraterrestrial hypothesis Fermi paradox Great Filter Hypothetical types of biochemistry Interplanetary contamination Kardashev scale Mediocrity principle Neocatastrophism Panspermia Planetarium hypothesis Rare Earth hypothesis Sentience quotient Zoo hypothesis Related topics Astrobiology Astroecology Biosignature Rejection of Earth - based abiogenesis ( Fred Hoyle ) Brookings Report Planetary protection Potential cultural impact of extraterrestrial contact Exotheology Extraterrestrials in fiction Extremophile Nexus for Exoplanet System Science Noogenesis San Marino Scale Technosignature UFO religion Xenoarchaeology Evolutionary biology Evolutionary history of life Index of evolutionary biology articles Introduction Outline of evolution Timeline of evolution Evolution Abiogenesis Adaptation Adaptive radiation Cladistics Coevolution Common descent Cospeciation Convergence Divergence Earliest known life forms Evidence of common descent Extinction Event Gene - centered view Homology Last universal common ancestor Macroevolution Microevolution Origin of life Panspermia Parallel evolution Prehistoric Autopsy Speciation Taxonomy Population genetics Biodiversity Gene flow Genetic drift Mutation Natural selection Variation Development Canalisation Evolutionary developmental biology Inversion Modularity Phenotypic plasticity Of taxa Birds origin Brachiopods Cephalopods Dinosaurs Fish Fungi Insects butterflies Life Mammals cats dogs dolphins and whales horses primates humans lemurs sea cows wolves Molluscs Plants Reptiles Spiders Tetrapods Viruses influenza Of organs Cell DNA Flagella Eukaryotes symbiogenesis chromosome endomembrane system mitochondria nucleus plastids In animals eye hair auditory ossicle nervous system brain Of processes Aging Death Programmed cell death Avian flight Biological complexity Cooperation Color vision in primates Emotion Empathy Ethics Eusociality Immune system Metabolism Monogamy Morality Mosaic evolution Multicellularity Sexual reproduction Gamete differentiation / sexes Life cycles / nuclear phases Mating types Sex - determination Snake venom Tempo and modes Gradualism / Punctuated equilibrium / Saltationism Micromutation / Macromutation Uniformitarianism / Catastrophism Speciation Allopatric Anagenesis Catagenesis Cladogenesis Ecological Hybrid Parapatric Peripatric Reinforcement Sympatric History Renaissance and Enlightenment Transmutation of species Charles Darwin On the Origin of Species History of paleontology Transitional fossil The eclipse of Darwinism Modern synthesis History of molecular evolution Extended evolutionary synthesis Philosophy Darwinism Alternatives to evolution by natural selection Catastrophism Lamarckism Orthogenesis Mutationism Saltationism Structuralism Spandrel Theistic Vitalism Related Biogeography Ecological genetics Molecular evolution Phylogenetics Tree Polymorphism Protocell Systematics Category Commons Portal WikiProject Molecules detected in outer space Molecules Diatomic Aluminium monochloride Aluminium monofluoride Aluminium monoxide Argonium Carbon monophosphide Carbon monosulfide Carbon monoxide Carborundum Cyanogen radical Diatomic carbon Fluoromethylidynium Hydrogen chloride Hydrogen fluoride Hydrogen ( molecular ) Hydroxyl radical Iron ( II ) oxide Magnesium monohydride cation Methylidyne radical Nitric oxide Nitrogen ( molecular ) Nitrogen monohydride Nitrogen sulfide Oxygen ( molecular ) Phosphorus monoxide Phosphorus mononitride Potassium chloride Silicon carbide Silicon mononitride Silicon monoxide Silicon monosulfide Sodium chloride Sodium iodide Sulfur monohydride Sulfur monoxide Titanium oxide Triatomic Aluminium hydroxide Aluminium isocyanide Amino radical Carbon dioxide Carbonyl sulfide CCP radical Chloronium Diazenylium Dicarbon monoxide Disilicon carbide Ethynyl radical Formyl radical Hydrogen cyanide ( HCN ) Hydrogen isocyanide ( HNC ) Hydrogen sulfide Hydroperoxyl Iron cyanide Isoformyl Magnesium cyanide Magnesium isocyanide Methylene radical Nitrous oxide Nitroxyl Ozone Phosphaethyne Potassium cyanide Protonated molecular hydrogen Sodium cyanide Sodium hydroxide Silicon carbonitride c - Silicon dicarbide Silicon naphthalocyanine Sulfur dioxide Thioformyl Thioxoethenylidene Titanium dioxide Tricarbon Water Four atoms Acetylene Ammonia Cyanic acid Cyanoethynyl Cyclopropynylidyne Formaldehyde Fulminic acid HCCN Hydrogen peroxide Hydromagnesium isocyanide Isocyanic acid Isothiocyanic acid Ketenyl Methylene amidogen Methyl radical Propynylidyne Protonated carbon dioxide Protonated hydrogen cyanide Silicon tricarbide Thioformaldehyde Tricarbon monoxide Tricarbon sulfide Thiocyanic acid Five atoms Ammonium ion Butadiynyl Carbodiimide Cyanamide Cyanoacetylene Cyanoformaldehyde Cyanomethyl Cyclopropenylidene Formic acid Isocyanoacetylene Ketene Methane Methoxy radical Methylenimine Propadienylidene Protonated formaldehyde Protonated formaldehyde Silane Silicon - carbide cluster Six atoms Acetonitrile Cyanobutadiynyl radical E-Cyanomethanimine Cyclopropenone Diacetylene Ethylene Formamide HC N Ketenimine Methanethiol Methanol Methyl isocyanide Pentynylidyne Propynal Protonated cyanoacetylene Seven atoms Acetaldehyde Acrylonitrile Vinyl cyanide Cyanodiacetylene Ethylene oxide Hexatriynyl radical Methylacetylene Methylamine Methyl isocyanate Vinyl alcohol Eight atoms Acetic acid Aminoacetonitrile Cyanoallene Ethanimine Glycolaldehyde Heptatrienyl radical Hexapentaenylidene Methylcyanoacetylene Methyl formate Propenal Nine atoms Acetamide Cyanohexatriyne Cyanotriacetylene Dimethyl ether Ethanol Methyldiacetylene Octatetraynyl radical Propene Propionitrile Ten atoms or more Acetone Benzene Buckminsterfullerene ( C fullerene, buckyball ) C fullerene Cyanodecapentayne Cyanopentaacetylene Cyanotetra - acetylene Ethylene glycol Ethyl formate Methyl acetate Methyl - cyano - diacetylene Methyltriacetylene Propanal n - Propyl cyanide Pyrimidine Deuterated molecules Ammonia Ammonium ion Formaldehyde Formyl radical Heavy water Hydrogen cyanide Hydrogen deuteride Hydrogen isocyanide Methylacetylene Trihydrogen cation Unconfirmed Anthracene Dihydroxyacetone Ethyl methyl ether Glycine Graphene H NCO Linear C Naphthalene cation Phosphine Pyrene Silylidine Related Abiogenesis Astrobiology Astrochemistry Atomic and molecular astrophysics Chemical formula Circumstellar envelope Cosmic dust Cosmic ray Cosmochemistry Diffuse interstellar band Earliest known life forms Extraterrestrial life Extraterrestrial liquid water Forbidden mechanism Helium hydride ion Homochirality Intergalactic dust Interplanetary medium Interstellar medium Photodissociation region Iron -- sulfur world theory Kerogen Molecules in stars Nexus for Exoplanet System Science Organic compound Outer space PAH world hypothesis Panspermia Polycyclic aromatic hydrocarbon ( PAH ) RNA world hypothesis Spectroscopy Tholin Book : Chemistry Category : Astrochemistry Category : Molecules Portal : Astrobiology Portal : Astronomy Portal : Chemistry Astrobiology portal Biology portal Evolutionary biology portal Geology portal Paleontology portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Earliest_known_life_forms&oldid=810795468 '' Categories : Biological evolution Evolution Evolutionary biology Tree of life ( biology ) Earliest phenomena Talk Contents About Wikipedia Español Edit links This page was last edited on 17 November 2017, at 14 : 03. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: the first life forms to appear on earth were
Answer: putative fossilized microorganisms