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已知最古老的生命

维基百科，自由的百科全书
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

主条目：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

主条目：最后共同祖先

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（英语：phylogenetic bracketing）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. ^ 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 可免费查阅. PMID 34261651. doi:10.1126/sciadv.abf3963 可免费查阅. 
  2. ^ 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 可免费查阅. 
  3. ^ 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]. 
  4. ^ 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）. 
  5. ^ 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 可免费查阅. PMID 29255053. doi:10.1073/pnas.1718063115 可免费查阅. 
  6. ^ 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. ^ 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）. 
  8. ^ 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）. 
  9. ^ 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 可免费查阅. 
  10. ^ 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）. 
  11. ^ 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 可免费查阅. PMID 29349297. doi:10.1126/sciadv.aao3521. 
  12. ^ 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. 
  13. ^ 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）. 
  14. ^ 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 可免费查阅. PMID 30127539. doi:10.1038/s41559-018-0644-x. 

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