Timeline
Information
____________________________________________________________________
Biological
Events Timeline: (MY = Million years before present)
- First bacteria - 3500 MY
- Early eukaryotes - 1900-1700 MY
- Trace animal fossils - 1000 MY
- Abundant soft-bodied animals - 700
MY
- First fish - 505 MY
- Early land plants - 438 MY
- First amphibians - 370 MY
- First reptiles - 310 MY
- End Permian mass extinction event (destroyed
82% of all genera) - 245 MY
- Dinosaurs appear - 240 MY
- First mammals - 225 MY
- First birds - 200 MY
- Flowering plants appear - 140 MY
- End Cretaceous mass extinction event
(including last dinosaurs); age of mammals begins - 66 to 65 MY
- Early horses adn other familiar animals
- 37 MY
- Earliest humans - 2 MY
- Humans dominant - 0 MY (now)
Geological Events Timeline:
- Formation of Earth - 4600 MY
- Oldest rocks yet discovered - 3950
MY
- Significant oxygen in atmosphere -
1500 MY
- Start of formation of Appalachian Mountains
- 450 MY
- Start of supercontinent Pangaea (all
continents pushed together) - 360 MY
- Abundant coal-forming swamps - 320
MY
- Break-up of Pangaea begins 225 MY
- Massive volcanic activity marking opening
of north Atlantic Ocean - 60 MY
- Formation of Rocky Mountains - 60 MY
- Major deformation of Alps and Himalayas
- 50 MY
- Ice Age which covered much of Ohio
- 1.6 MY to 10,000 years
- Hawaii (big island) eruptions start
- 0.7 MY
- Eruption of Mount St. Helens - 0 MY
(May 1980)
Geological Eras Information:
- Archaean Era 3600-4600 MY(origin
of life, beginning of photosynthesis, increaed abundance of oxygen in atmosphere,
diversification of prokaryotes)
- Proterozoic Era 2500-3600 MY(earliest
eukaryotes, trace animal fossils, first multicellular fossils)
- Paleozoic Era 290-2500 MY
- Cambrian Period 543-2500 MY(marine
animals diversify, diverse algae)
- Ordovician Period 500-543 MY(diversification
of invertebrates, mass extinction at the end of this period)
- Sulurian Period 439-500 MY(earliest
terrestrial vascular plants)
- Devonian Period 409-439 MY(diversification
of boney fishes, mass extinction at the end of this period)
- Carboniferous Period 354-409 MY(Gondwanaland
and small northern continents form, early winged insects, first reptiles)
- Permian Period 290-354 MY(Pangaea,
glaciations, major mass extinction of marine life at end of this period)
- Mesozoic Era 144-290 MY
- Triassic Period 251-290 MY(continents
begin to separate, first dinosaurs, first mammals)
- Jurassic Period 206-251 MY(first
birds, gymnosperms dominate, evolution of angiosperms)
- Cretaceous Period 144-206 MY(most
continents separated, mass extinction at end of period including dinosaurs)
- Cenozoic Era 0.01-144 MY
- Tertiary Period 5.2-144 MY (continentss
near modern positions, climate cools, radiation of mammals, birds, snakes,
pollinating insects, angiosperms)
- Paleocene Epoch 65-144 MY
- Eocene Epoch 55.6-65 MY
- Oligocene Epoch 33.5-55.6 MY
- Miocene Epoch 23.8-33.5 MY
- Pliocene Epoch 5.2-23.8 MY
- Quaternary Period 0.01-5.2 MY (continents
in modern positions, repeated glaciations, lowering of sea level, extinctions
of large mammals, evolution of Homo erectus and Homo sapiens,
rise of agriculture)
- Pleistocene Epoch 1.8-5.2 MY
- Recent (Holocene) Epoch 0.01-1.8
MY
Other Information on the Age and History
of the Earth is Available at:
- The
Age of the Earth - a page that discusses evidence dating the earth, it
is a highly scientific analysis but good background for advanced classes
- The
Geologic Time Scale - a page explaining divisions in the geologic time
scale and the principles and theories on which the time scale is based
This information was adapted from a compilation
of resources including Evoluationary Biology by Douglas J. Futuyma, Sunderland,
MA: Sinauer Associates, Inc. 1998.
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