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"Deep time" by Ariadne Unst

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Ecology notes. Evolution notes.

"Deep time" describes geological time scales

Eras of geological time

This table based in part on data published by John McPhee in Wild Earth (Summer 2002).

Cenozoic Era
(65 MYA to today)
Quaternary (1.8 MYA to today)
  • Holocene
    (11 KYA to today)
  • Pleistocene
    (1.8 MYA to 11 KYA)
    (18 KYA = maximum
    extent of glaciers
    in North America)
Tertiary (65 MYA to 1.8 MYA)
  • Pliocene (5 MYA to 1.8 MYA)
    "more recent"; almost half of its mollusks have survived extinction; includes 4 pulses of glaciation.
  • Miocene (23 MYA to 5 MYA)
    "moderately recent"; 15% of its mollusk species have survived extinction.
  • Oligocene (38 MYA to 23 MYA)
    "but a little recent".
  • Eocene (54 MYA to 38 MYA)
    "dawn of the recent"; under 4% of its mollusk species have survived extinction.
  • Paleocene (65 MYA to 38 MYA)
    "old recent".
Mesozoic Era
(245 MYA to 65 MYA)
Cretaceous
(146 MYA to 65 MYA)
e.g. opossum.
Jurassic
(208 MYA to 146 MYA)
Triassic
(245 MYA to 208 MYA)
e.g. oysters.
Paleozoic Era
(544 MYA to 245 MYA)
Permian
(286 MYA to 245 MYA)
Carboniferous
(360 MYA to 286 MYA)
  • Pennsylvanian
    (325 MYA to 286 MYA)
  • Mississippian
    (360 MYA to 325 MYA)
Devonian
(410 MYA to 360 MYA)
e.g. some clams.
Silurian
(440 MYA to 410 MYA)
Ordovician
(505 MYA to 440 MYA)
Cambrian
(554 MYA to 505 MYA)
Precambrian Time
(4500 MYA to 544 MYA)

(second 2 billion years)
Aerobic life appeared, probably in Helikan or Hadrynian times.
Archean Eon
(first 2 billion years)
Photosynthesis began in the middle Archean