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A mathematical model for mass extinction. ... The importance of extinction to the development of life leads us to some crucial questions about the process, the most fundamental of which is this: is extinction a natural part of the evolution process, or is it simply a chance result of occasional catastrophes besetting...
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www.lassp.cornell.edu/newmme/science/extinction.html
www.lassp.cornell.edu/newmme/science/extinction.html
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Extinction event - Wikipedia, the free encyclopedia
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An extinction event (also known as: mass extinction ; extinction-level event , ELE) is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect mos...
en.wikipedia.org/wiki/Extinction_event
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Here are details of the five worst mass extinctions in Earths history and their possible causes, according to paleobiologist Doug Erwin of the Smithsonian Institutions National Museum of Natural History. Erwin said estimates ofextinction rates are from the late John J. Sepkoski at the University of Chicago.
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www.space.com/scienceastronomy/planetearth/extinction_s...
www.space.com/scienceastronomy/planetearth/extinction_sidebar_000907.html
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It was originally named the Trias in 1834 by the geologist Friedrich August Von Alberti, as in Germany the period consisted of 3 rock types (tri meaning 3). At the top of the youngest of these beds there is evidence for a Mass Extinction which occurred approximately 200 million years ago.
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palaeo.gly.bris.ac.uk/Palaeofiles/Triassic/titlepage.ht...
palaeo.gly.bris.ac.uk/Palaeofiles/Triassic/titlepage.htm
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How do we define a Mass Extinction? Traditionally, within geological sciences, mass extinctions have been seen as some type of catastrophe for the world's biota. ... The definition of mass extinction is somewhat difficult because the word 'catastrophe' is almost always used in relation to human life or property loss,
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ethomas.web.wesleyan.edu/ees123/mass_extinctions.htm
ethomas.web.wesleyan.edu/ees123/mass_extinctions.htm
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mass extinction, the extinction of a large percentage of the earth's species, opening ecological niches for other species to fill. There have been at least ten such events. ... The best-known mass extinction is that at the end of the Cretaceous period, when the dinosaurs and many other plants and animals disappeared and up...
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www.infoplease.com/ce6/sci/A0832139.html
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Examines dinosaur extinction, mass and background extinctions, and the Earth's major, periodic extinctions. ... MASS EXTINCTIONS; A mass extinction is a relatively sudden, global decrease in the diversity of life forms. Mass extinctions have occurred periodically throughout the existence of life on Earth. To be a...
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www.enchantedlearning.com/subjects/dinosaurs/extinction...
www.enchantedlearning.com/subjects/dinosaurs/extinction/
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The Permian mass extinction occurred about 248 million years ago and was the greatest mass extinction ever recorded in earth history; even larger than the previously discussed Ordovician and Devonian crises and the better known End Cretaceous extinction that felled the dinosaurs.
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hannover.park.org/Canada/Museum/extinction/permass.html
hannover.park.org/Canada/Museum/extinction/permass.html
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