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Evolution of Life

When these happened

25 dated records from 2 BCE to 2029. Each is drawn as wide as its date is certain — a band is a band because nobody knows the year, not because the drawing is imprecise.

0500100015002000The origin of life — by c. 3.5 Ga; contested claims to c. 4.2 GaThe Great Oxidation Event — c. 2.43–2.22 GaThe end-Ordovician mass extinction — c. 445.2–443.8 MaThe Cambrian explosion — c. 538.8–515 MaThe Cretaceous–Palaeogene mass extinction — 66.043 ± 0.043 MaThe end-Triassic mass extinction — c. 201.4 MaThe end-Permian mass extinction — 251.902 ± 0.024 MaThe Late Devonian crisis — c. 372 Ma and c. 359 MaWalcott locates the Burgess Shale beds — 1909Sprigg notices impressions at the Ediacara mine — 1946The Cambridge re-description of the Burgess fauna begins — from 1971The Alvarez impact hypothesis is published — 1980Hou Xianguang finds the Chengjiang fauna — 1984Chicxulub is identified as the K–Pg impact crater — 1991Carbon-isotope evidence reported from 3.7 Ga Isua sediments — 1999Sulfur mass-independent fractionation is proposed as an atmospheric oxygen proxy — 2000Centimetre-scale structures reported from 2.1 Ga Gabonese shales — 2010The K–Pg boundary is dated to 66.043 ± 0.043 Ma — 2013The end-Permian extinction is resolved to about sixty thousand years — 2014IODP–ICDP Expedition 364 drills the Chicxulub peak ring — 2016 (April–May)Structures at Isua are reported as 3.7 Ga stromatolites — 2016Haematite filaments are reported from Nuvvuagittuq vent precipitates — 2017The Isua stromatolite claim is reassessed and rejected — 2018The numerical age of the Cambrian base is revised to 538.8 Ma — ICS chart, 2020s (edition not confirmed)LUCA is dated to about 4.2 Ga by phylogenomic analysis — 2024
25 shown · 25 dated · 0 cannot be placed on an axis · Approximate or contested. Draw a band and do not sharpen its edges.
In order25
  1. by c. 3.5 Ga; contested claims to c. 4.2 GaThe origin of lifesources disagree about the date

    Sources disagree, or the dating is contested. Stated, not resolved.

  2. c. 2.43–2.22 GaThe Great Oxidation Event

    It happened, and the record is settled.

  3. c. 445.2–443.8 MaThe end-Ordovician mass extinction

    It happened, and the record is settled.

  4. c. 538.8–515 MaThe Cambrian explosion

    It happened, and the record is settled.

  5. 66.043 ± 0.043 MaThe Cretaceous–Palaeogene mass extinction

    It happened, and the record is settled.

  6. c. 201.4 MaThe end-Triassic mass extinction

    It happened, and the record is settled.

  7. 251.902 ± 0.024 MaThe end-Permian mass extinction

    It happened, and the record is settled.

  8. c. 372 Ma and c. 359 MaThe Late Devonian crisis

    It happened, and the record is settled.

  9. 1909Walcott locates the Burgess Shale beds

    It happened, and the record is settled.

  10. 1946Sprigg notices impressions at the Ediacara mine

    It happened, and the record is settled.

  11. from 1971The Cambridge re-description of the Burgess fauna begins

    It happened, and the record is settled.

  12. 1980The Alvarez impact hypothesis is published

    It happened, and the record is settled.

  13. 1984Hou Xianguang finds the Chengjiang fauna

    It happened, and the record is settled.

  14. 1991Chicxulub is identified as the K–Pg impact crater

    It happened, and the record is settled.

  15. 1999Carbon-isotope evidence reported from 3.7 Ga Isua sediments

    It happened, and the record is settled.

  16. 2000Sulfur mass-independent fractionation is proposed as an atmospheric oxygen proxy

    It happened, and the record is settled.

  17. 2010Centimetre-scale structures reported from 2.1 Ga Gabonese shales

    Sources disagree, or the dating is contested. Stated, not resolved.

  18. 2013The K–Pg boundary is dated to 66.043 ± 0.043 Ma

    It happened, and the record is settled.

  19. 2014The end-Permian extinction is resolved to about sixty thousand years

    It happened, and the record is settled.

  20. 2016 (April–May)IODP–ICDP Expedition 364 drills the Chicxulub peak ring

    It happened, and the record is settled.

  21. 2016Structures at Isua are reported as 3.7 Ga stromatolites

    Sources disagree, or the dating is contested. Stated, not resolved.

  22. 2017Haematite filaments are reported from Nuvvuagittuq vent precipitates

    Sources disagree, or the dating is contested. Stated, not resolved.

  23. 2018The Isua stromatolite claim is reassessed and rejected

    It happened, and the record is settled.

  24. ICS chart, 2020s (edition not confirmed)The numerical age of the Cambrian base is revised to 538.8 Ma

    Sources disagree, or the dating is contested. Stated, not resolved.

  25. 2024LUCA is dated to about 4.2 Ga by phylogenomic analysis

    Sources disagree, or the dating is contested. Stated, not resolved.