Word: sepkoski
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...circles the sun far beyond the orbit of Pluto--sending them hurtling toward earth. Others assign that role to Planet X, while some insist that the slow, bobbing ride of the sun and its planets around the Milky Way galaxy is responsible. Whatever the details, declares Paleontologist J. John Sepkoski Jr. of the University of Chicago, the evidence for periodic mass extinctions "very strongly implicates an extraterrestrial mechanism...
Under the Raup and Sepkoski model of cyclical changes, the world is periodically wiped clean, leaving the evolutionary process with an empty slate...
Moreover, if Kaup and Sepkoski are right, the implications stretch far into the heart of evolutionary science. Most scientists believe that races and species die out primarily as a result of genetic deficiencies, but the so-called "Death Star" theory may imply that extinctions are simply cases of bad luck...
Within days of the Raup-Sepkoski announcement, word of their work quickly spread to other areas of science. Astronomers leaped into the fray with the greatest zeal, and before long, the race was on to explain one of the most intriguing theories of life on earth...
...filled galaxy takes about 67 million years, and the sun slips through the most crowded region every 33 million years. During this time it could be blocked by the debris. The 33 million-year period corresponds roughly to the 26-million year cycle of extinction postulated by Raup and Sepkoski and the differences between the two figures can be accounted for by uncertainties in astronomical and geological datings, say the originators of the theory, Richard Smothers and Michael Rampino...
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