Cambrian Life Explosion Period (540MYA to 520MYA)

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A Cambrian Life Explosion Period (540MYA to 520MYA) is a time period within the Cambrian period during the Paleozoic Era that included the emergence of aquatic multicellular, eukaryotic organisms.

References

2022

  • (Wikipedia, 2022) ⇒ https://en.wikipedia.org/wiki/Cambrian_explosion Retrieved:2022-8-21.
    • The Cambrian explosion, Cambrian radiation, Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately in the Cambrian Period when practically all major animal phyla started appearing in the fossil record.[1] It lasted for about 13 [2] [3]  – 25[4] million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well. Before early Cambrian diversification,most organisms were relatively simple, composed of individual cells, or small multicellular organisms, occasionally organized into colonies. As the rate of diversification subsequently accelerated, the variety of life became much more complex, and began to resemble that of today.[5] Almost all present-day animal phyla appeared during this period.[6][7] A 2019 paper suggests that the timing should be expanded back to include the late Ediacaran, rather than just the narrower timeframe of the "Cambrian Explosion" event visible in the fossil record, based on analysis of chemicals that would have laid the building blocks for a progression of transitional radiations starting with the Ediacaran period and continuing at a similar rate into the Cambrian.
  1. ↑ "Stratigraphic Chart 2022" (PDF). International Stratigraphic Commission. February 2022. Retrieved 22 April 2022.
  2. ↑ Calibrating rates of early Cambrian evolution, Science 1993, 261(5126), s. 1293–1298. SA Bowring, JP Grotzinger, CE Isachsen, AH Knoll, SM Pelechaty, P Kolosov
  3. ↑ Valentine1999">Valentine, JW; Jablonski, D; Erwin, DH (1999). "Fossils, molecules and embryos: new perspectives on the Cambrian explosion". Development. 126 (5): 851–9. doi:10.1242/dev.126.5.851. PMID 9927587.
  4. ↑ Kouchinsky, A.; Bengtson, S.; Runnegar, B. N.; Skovsted, C. B.; Steiner, M.; Vendrasco, M. J. (2012). "Chronology of early Cambrian biomineralization". Geological Magazine. 149 (2): 221–251.
  5. ↑ Bambach, R.K.; Bush, A.M.; Erwin, D.H. (2007). "Autecology and the filling of Ecospace: Key metazoan radiations". Palæontology. 50 (1): 1–22. doi:10.1111/j.1475-4983.2006.00611.x.
  6. ↑ Budd, G. E.; Jensen, S. (2000). "A critical reappraisal of the fossil record of the bilaterian phyla". Biological Reviews of the Cambridge Philosophical Society. 75 (2): 253–95. doi:10.1111/j.1469-185X.1999.tb00046.x. PMID 10881389. S2CID 39772232.
  7. ↑ Budd, G.E. (2003). "The Cambrian Fossil Record and the Origin of the Phyla". Integrative and Comparative Biology. 43 (1): 157–165. doi:10.1093/icb/43.1.157. PMID 21680420.

2016

  • (Fox, 2016) ⇒ Douglas Fox. (2016) "What sparked the Cambrian explosion?.” In: Nature, 530(268–270) doi:10.1038/530268a
    • QUOTE: The emerging evidence about oxygen thresholds and ecology could also shed light on another major evolutionary question: when did animals originate? The first undisputed fossils of animals appear only 580 million years ago, but genetic evidence indicates that basic animal groups originated as far back as 700 million to 800 million years ago. According to Lyons, the solution may be that oxygen levels rose to perhaps 2% or 3% of modern levels around 800 million years ago. These concentrations could have sustained small, simple animals, just as they do today in the ocean's oxygen-poor zones. But animals with large bodies could not have evolved until oxygen levels climbed higher in the Ediacaran.
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