維基百科

生命進化史

(由古生物跳轉過嚟)

生命進化史（粵拼：sang1 ming6 zeon3 faa3 si2）係指地球上嘅生命進化嘅歷史。

地球係目前宇宙已知行星入面唯一能夠維持生命嘅[1]。一般認為大約 40 億年前嘅高能化學反應產生咗能夠複製自己嘅分子，打後 5 億年就出現咗所有生命嘅共同祖先，再分化咗細菌同古菌出嚟[2]。早期嘅生命體發展出搞光合作用嘅能力，於是有得直接利用太陽能向大氣嗰度釋放啲氧氣。大氣度積累嘅氧氣俾太陽射嘅紫外線作用，喺上層大氣形成咗臭氧（O3），出現咗臭氧層[3]。早期嘅生命以原核生物（以單一原核細胞組成嘅生物）嘅形態存在。由於臭氧層吸收咗太陽射落嚟嘅紫外線，陸地變到好啱生命生存，所以生命開始喺陸地上面繁衍[4]。目前已知最早嘅生命化石證據有西澳洲砂岩入面揾到嘅 34.8 億年前嘅微生物墊化石[5][6][7][8]、西格陵蘭變質碎屑岩度 37 億年前嘅生源石墨[9]、仲有西澳洲岩石度 41 億年前嘅生物質殘骸[10]。

距離而家大約 5.42 億年前發生咗寒武紀生命大爆發（Cambrian explosion）。由化石睇，嗰時地球上嘅多細胞生物種類突然之間多咗好多，包括節肢動物三葉蟲、奇蝦等[11]。化石記錄顯示大多數嘅動物門都係喺呢個時期出現嘅[12][13]。呢個時期持續咗大約 2 千萬年至 2 千 5 百萬年，導致咗大多數現代動物門嘅發散。複雜啲嘅生物多咗好多，生物多樣性大幅噉提高，所以佢俾人話係生命嘅大爆發。

喺後少少嘅 5 億年前嘅奧陶紀（Ordovician）地球有咗脊椎動物－甲冑魚。打後嘅化石記錄顯示地球又有咗幾次生物物種嘅大規模增加或者滅絕[14]，最近嗰次係 6 千 6 百萬年前嘅白堊紀－第三紀滅絕事件（Cretaceous–Paleogene extinction event），呢次事件引致咗恐龍嘅滅絕，但係一啲細隻嘅動物－當中有哺乳類－走得甩死唔去，令到地球嘅生命持續落去。嗰次之後，哺乳類開始變到愈嚟愈發達，而幾百萬年前嘅非洲嘅類猿動物似乎開始用兩隻腳行，空咗對手出嚟令到佢哋可以整工具，個腦又變到愈嚟愈大－慢慢進化成智人（Homo sapien）[15]。智人嘅各種活動產生咗世界嘅各大文明同科技。

各種猿類動物（包括人）嘅骨骼

引述

編輯
  1. ↑ Purves, W. K.; Sadava, D.; Orians, G. H.; Heller, C. Life, the Science of Biology: The Science of Biology. Macmillan. 2001: 455.
  2. ↑ Doolittle, W. F.; Worm, B.. Uprooting the tree of life (PDF). Scientific American. February 2000, 282 (6): 90–95.
  3. ↑ Zimmer, C. Earth’s Oxygen: A Mystery Easy to Take for Granted. New York Times. 2013-10-03 [2013-10-03].
  4. ↑ Burton, K. Astrobiologists Find Evidence of Early Life on Land 互聯網檔案館嘅歸檔，歸檔日期2011年10月11號，.. NASA.
  5. ↑ Schopf, J. W.; Kudryavtsev, A. B.; Czaja, A. D.; Tripathi, A. B. Evidence of Archean life: Stromatolites and microfossils. Precambrian Research (Amsterdam, the Netherlands: Elsevier). 2007-10-05, 158 (3–4): 141–155.
  6. ↑ Schopf, J. W. Fossil evidence of Archaean life. Philosophical Transactions of the Royal Society B (London: 皇家學會). 2006-06-29, 361 (1470): 869–885.
  7. ↑ Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M. Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia. Astrobiology (journal). 2013-11-08, 13 (12): 1103–24 [2013-11-15].
  8. ↑ Oldest fossil found: Meet your microbial mom
  9. ↑ Ohtomo, Y.; Kakegawa, T.; Ishida, A.; et al. Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks. Nature Geoscience (London: 自然出版集團). January 2014, 7 (1): 25–28.
  10. ↑ Borenstein, S. Hints of life on what was thought to be desolate early Earth. Excite (Yonkers, NY: Mindspark Interactive Network). Associated Press. 2015-10-19 [2015-10-20].
  11. ↑ Kirschvink, J. L. Schopf, J.W.; Klein, C. and Des Maris, D, Ed. Late Proterozoic low-latitude global glaciation: the Snowball Earth. The Proterozoic Biosphere: A Multidisciplinary Study. Cambridge University Press. 1992: 51–52.
  12. ↑ Maloof, A. C.; Porter, S. M.; Moore, J. L.; Dudas, F. O.; Bowring, S. A.; Higgins, J. A.; Fike, D. A.; Eddy, M. P. The earliest Cambrian record of animals and ocean geochemical change. Geological Society of America Bulletin. 2010, 122 (11–12): 1731–1774.
  13. ↑ New Timeline for Appearances of Skeletal Animals in Fossil Record Developed by UCSB Researchers
  14. ↑ Raup, D. M.; Sepkoski Jr, J. J. Mass Extinctions in the Marine Fossil Record. Science. 1982, 215 (4539): 1501–03.
  15. ↑ Wilkinson, B. H.; McElroy, B. J. The impact of humans on continental erosion and sedimentation. Bulletin of the Geological Society of America. 2007, 119 (1–2): 140–56 [2007-04-22].
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