Devon Tengah

Devon Tengah adalah kala kedua dari Periode Devon, yang dimulai pada 393.3 juta tahun lalu, hingga 382.7 juta tahun lalu^[1] Kala ini dibagi menjadi dua sub-kala, yaitu Eifelium dan Givetium.

Peristiwa

Pada saat ini, ikan jenis Agnatha yang tak berahang mulai berkurang keanekaragamannya di lingkungan laut dan air tawar karena perubahan iklim yang drastis, juga meningkatnya persaingan dan predasi serta berkembagnya ikan berahang. Wilayah air periode Devon yang hangat, dangkal dan sedikit oksigen serta dikelilingi oleh tumbuhan primitif, Memberi lingkunagn yang ideal untuk ikan purba mengembangkan karaksteristik penting seperti paru-paru dan kemampuan untuk merangkak keluar dari air.^[2]

Devon Tengah juga melihat meluasnya pohon dan semak-semak pada lingkungan darat di seluruh dunia.^[3]

Referensi

^ "Geologic TimeScale Foundation - Stratigraphic Information". timescalefoundation.org. Diakses tanggal 2021-10-30.
^ Clack, Jennifer (13 August 2007). "Devonian climate change, breathing, and the origin of the tetrapod stem group". Integrative and Comparative Biology. 47 (4): 510–523. doi:10.1093/icb/icm055  . PMID 21672860. Estimates of oxygen levels during this period suggest that they were unprecedentedly low during the Givetian and Frasnian periods. At the same time, plant diversification was at its most rapid, changing the character of the landscape and contributing, via soils, soluble nutrients, and decaying plant matter, to anoxia in all water systems. The co-occurrence of these global events may explain the evolution of air-breathing adaptations in at least two lobe-finned groups, contributing directly to the rise of the tetrapod stem group.
^ Algeo, Thomas J.; Scheckler, Stephen E. (1998-01-29). Beerling, D. J.; Chaloner, W. G.; Woodward, F. I., ed. "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences (dalam bahasa Inggris). 353 (1365): 113–130. doi:10.1098/rstb.1998.0195. ISSN 0962-8436. PMC 1692181  . Pemeliharaan CS1: Format PMC (link)

[1] "Geologic TimeScale Foundation - Stratigraphic Information". timescalefoundation.org. Diakses tanggal 2021-10-30.

[2] Clack, Jennifer (13 August 2007). "Devonian climate change, breathing, and the origin of the tetrapod stem group". Integrative and Comparative Biology. 47 (4): 510–523. doi:10.1093/icb/icm055  . PMID 21672860. Estimates of oxygen levels during this period suggest that they were unprecedentedly low during the Givetian and Frasnian periods. At the same time, plant diversification was at its most rapid, changing the character of the landscape and contributing, via soils, soluble nutrients, and decaying plant matter, to anoxia in all water systems. The co-occurrence of these global events may explain the evolution of air-breathing adaptations in at least two lobe-finned groups, contributing directly to the rise of the tetrapod stem group.

[3] Algeo, Thomas J.; Scheckler, Stephen E. (1998-01-29). Beerling, D. J.; Chaloner, W. G.; Woodward, F. I., ed. "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences (dalam bahasa Inggris). 353 (1365): 113–130. doi:10.1098/rstb.1998.0195. ISSN 0962-8436. PMC 1692181  . Pemeliharaan CS1: Format PMC (link)

[1]

[2]

[3]