Ìgbà Dẹfoníà

The Devonian is a geologic period and system of the Paleozoic Era spanning from 416 to 359.2 ẹgbẹgbẹ̀rún ọdún sẹ́yìn (ICS, 2004,^[5] chart). It is named after Devon, England, where rocks from this period were first studied.

Ìgbà Dẹfoníà

Ìgbà Dẹfoníà 416–359.2 ẹgbẹgbẹ̀rún ọdun sẹ́yìn PreЄ Є O S D C P T J K Pg N
Mean atmospheric O2 content over period duration	ca. 15 Vol %[1] (75 % of modern level)
Mean atmospheric CO2 content over period duration	ca. 2200 ppm[2] (8 times pre-industrial level)
Mean surface temperature over period duration	ca. 20 °C[3] (6 °C above modern level)
Sea level (above present day)	Relatively steady around 180m, gradually falling to 120m through period[4]

During the Devonian Period the pectoral and pelvic fins of lobe-finned fish evolved into legs^[6] as they started to walk on land as tetrapods around 397 Ma.^[7] Various terrestrial arthropods also became well-established.