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 380 million years ago

Mean atmospheric O2
 75% of modern level

Mean atmospheric CO2
 8x pre-industrial level

Mean temperature
 6C above modern level


Paleozoic Earth - Devonian canopy of Archaeopteris trees - Natural History Illustration Geologic Time Scale

 Era: Paleozoic
  Period: Devonian
   Epoch: Late
    Age: Frasnian


Devonian canopy

The fossil record reveals that great forests of tree-like plants with fern-like leaves of the genus Archaeopteris covered much of the Earth 380 million years ago. The large umbrella-like fronds appear to have been optimized for gathering sunlight at the canopy level while permitting enough light to reach the shorter and younger trees. It was great forests like these that helped to draw much of the carbon dioxide out of the primeval atmosphere while releasing the oxygen we breathe today.



Copyright Walter B. Myers. All rights reserved.

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