已知最古老的生命
目前已发现的最早期生命是在海底热泉 沉积物 之中发现的[ 1] [ 2] [ 3]
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目前已知最古老的生命 是澳大利亚 附近海域的海底热泉 沉积物 中发现的大约34.2亿年前的微生物 化石 [ 1] [ 2] [ 4] [ 5] ,不过有的学者对此并不认可,认为这些在海底热泉沉积物中发现的东西并不是微生物化石[ 6] 。
科学界的一些理论认为生命最早应起源于37.7亿年前[ 2] [ 7] [ 7] 。也有学者认为生命应起源于42.8亿年前,即距今大约44.1亿年前海洋形成后数亿年间生命就出现了[ 2] [ 3] [ 8] 。
胚种论
一些理论认为地球上最早的生命来自外太空[ 9] [ 10] 。虽然目前没有直接证据支持这种理论,不过发表于2018年的一项研究在一颗距今大约45亿年前落到地球的陨石 上发现了水和有机物[ 11] 。
遗传学上的证据
对现在尚存的细菌以及古菌基因组进行分析并构建系统发育树 能找出一个“最后共同祖先 ”(LUCA),以及细菌与古菌之间共有的一些基因[ 12] [ 13] 。据分子钟 理论的计算,一些研究表明最后共同祖先大约出现于距今44.77到45.19亿年前,因为最后共同祖先一定是从最早期的生命进化来的,所以按照这一理论生命的出现应该至少不晚于至今44.77到45.19亿年前[ 7] [ 14] 。
参考资料
^ 1.0 1.1 Cavalazzi, Barbara; et al. Cellular remains in a ~3.42-billion-year-old subseafloor hydrothermal environment . Science Advances . 14 July 2021, 7 (9): eabf3963. Bibcode:2021SciA....7.3963C . PMC 8279515 . PMID 34261651 . doi:10.1126/sciadv.abf3963 .
^ 2.0 2.1 2.2 2.3 Dodd, Matthew S.; Papineau, Dominic; Grenne, Tor; slack, John F.; Rittner, Martin; Pirajno, Franco; O'Neil, Jonathan; Little, Crispin T. S. Evidence for early life in Earth's oldest hydrothermal vent precipitates (PDF) . Nature. 2 March 2017, 543 (7643): 60–64. Bibcode:2017Natur.543...60D . PMID 28252057 . S2CID 2420384 . doi:10.1038/nature21377 .
^ 3.0 3.1 Zimmer, Carl . Scientists Say Canadian Bacteria Fossils May Be Earth's Oldest . The New York Times. 1 March 2017 [2 March 2017] .
^ Tyrell, Kelly April. Oldest fossils ever found show life on Earth began before 3.5 billion years ago . University of Wisconsin–Madison . 18 December 2017 [18 December 2017] . (原始内容存档 于2021-02-10).
^ Schopf, J. William; Kitajima, Kouki; Spicuzza, Michael J.; Kudryavtsev, Anatolly B.; Valley, John W. SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions . PNAS . 2017, 115 (1): 53–58. Bibcode:2018PNAS..115...53S . PMC 5776830 . PMID 29255053 . doi:10.1073/pnas.1718063115 .
^ Brasier, Martin D.; Green, Owen R.; Lindsay, John F.; McLoughlin, Nicola; Steele, Andrew; Stoakes, Cris. Critical testing of Earth's oldest putative fossil assemblage from the ∼3.5Ga Apex chert, Chinaman Creek, Western Australia . Precambrian Research. 2005-10-21, 140 (1): 55–102. ISSN 0301-9268 . doi:10.1016/j.precamres.2005.06.008 (英语) .
^ 7.0 7.1 7.2 Staff. A timescale for the origin and evolution of all of life on Earth . Phys.org . 20 August 2018 [20 August 2018] . (原始内容存档 于2020-11-11).
^ Dunham, Will. Canadian bacteria-like fossils called oldest evidence of life . Reuters . 1 March 2017 [1 March 2017] . (原始内容存档 于2017-03-02).
^ Steele, Edward J.; et al. Cause of Cambrian Explosion - Terrestrial or Cosmic?. Progress in Biophysics and Molecular Biology . 1 August 2018, 136 : 3–23. PMID 29544820 . S2CID 4486796 . doi:10.1016/j.pbiomolbio.2018.03.004 .
^ McRae, Mike. A Weird Paper Tests The Limits of Science by Claiming Octopuses Came From Space . ScienceAlert . 28 December 2021 [29 December 2021] . (原始内容存档 于2021-12-29).
^ Chan, Queenie H. S. et al. Organic matter in extraterrestrial water-bearing salt crystals . Science Advances . 10 January 2018, 4 (1, eaao3521): eaao3521. Bibcode:2018SciA....4O3521C . PMC 5770164 . PMID 29349297 . doi:10.1126/sciadv.aao3521 .
^ Weiss, M.C.; Sousa, F. L.; Mrnjavac, N.; Neukirchen, S.; Roettger, M.; Nelson-Sathi, S.; Martin, W.F. The physiology and habitat of the last universal common ancestor. Nat Microbiol. 2016, 1 (9): 16116. PMID 27562259 . S2CID 2997255 . doi:10.1038/nmicrobiol.2016.116 .
^ Wade, Nicholas. Meet Luca, the ancestor of all living things . The New York Times. 25 July 2016 [8 October 2018] . (原始内容存档 于28 July 2016).
^ Betts, Holly C.; Putick, Mark N.; Clark, James W.; Williams, Tom A.; Donoghue, Philip C.J.; Pisani, Davide. Integrated genomic and fossil evidence illuminates life's early evolution and eukaryote origin . Nature . 20 August 2018, 2 (10): 1556–1562. PMC 6152910 . PMID 30127539 . doi:10.1038/s41559-018-0644-x .
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