An artistic rendition of mass extinction, of the five big mass extinction, according to Neil Shubin, each leaving a layer of fossil clues in layers of earth. [3]
In science, extinction periodicity hypothesis, or “Fischer-Arthur hypothesis”, is the hypothesis that mass extinctions, of the majority of existing earth-bound marine vertebrates, invertebrates, and protozoans, aka "life forms" in defunct layspeak, vary cynically, via causes unknown, possibly related to extraterrestrial forces (solar, solar system, or galactic), at a rate, according to fossil records of the last 250 million years, of 26-million years, among with there have been five big extinction events. [1]
Overview In 1977, Americans Alfred Fischer and Michael Arthur posited, without rigorous statistical testing, that mass extinctions occur cyclically ever 32-million years. [2]
In 1982, Jack Sepkoski finished a 10-year fossil data compilation project (1972-1982) of transforming the mass of known fossil data in Treatise on Invertebrate Paleontology, and other data bases, per suggestion of his PhD advisor Stephen Gould, into a computer database, in aims to discern possible patterns in the "history of life" (Neil Shubin, 2013), found that the data suggested five mass extinctions, and building on the so-called “extinction periodicity hypothesis” (or Fischer-Arthur hypothesis), introduced in 1977 by A.G. Fischer and M.A. Arthur, together with David Raup, hypothesized in 1984 (Ѻ) that mass extinctions occur, not randomly, but cyclically every 26-million years. [4]
References 1. (a) Sepkoski, Jack. (c.1983). “Periodicity”, in: The Evolutionary Process and the Fossil Record (§:2.12.3, pgs. 171-79). Publisher. (b) Raup, D.M. and Sepkoski, Jack. (1984). “Periodicity of Extinctions in Geological Past” (abs), Proceedings of the National Academy of Science of the United States of America, 81(3):801-05. 2. (a) Fischer, Alfred G. and Arthur, Michael A. (1977). “Secular Variations in the Pelagic Realm”, in: Deep-Water Carbonate Environments (editors: H.E. Cook and P. Enos) (pgs. 19-50). Special Publication of the Society of Economic Paleontologists and Mineralogists. No. 25. (b) Raup, D.M. and Sepkoski. (1984). “Periodicity of Extinctions in Geological Past” (abs), Proceedings of the National Academy of Science of the United States of America, 81(3):801-05. 3. Shubin, Neil. (2013). The Universe Within: Discovering the Common History of Rocks, Planets, and People (pgs. 130-39; photo, pg. 138). Random House.
