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biological extinction in earth historyVirtually all plant and animal species that have ever lived on the earth are extinct. For this reason alone, extinction must play an important role in the evolution of life. The five largest mass extinctions of the past 600 million years are of greatest interest, but there is also a spectrum of smaller events, many of which indicate biological systems in profound stress. Extinction may be episodic at all scales, with relatively long periods of stability alternating with short-lived extinction events. Most extinction episodes are biologically selective, and further analysis of the victims and survivors offers the greatest chance of deducing the proximal causes of extinction. A drop in sea level and climatic change are most frequently invoked to explain mass extinctions, but new theories of collisions with extraterrestrial bodies are gaining favor. Extinction may be constructive in a Darwinian sense or it may only perturb the system by eliminating those organisms that happen to be susceptible to geologically rare stresses.
Document ID
19860047319
Document Type
Reprint (Version printed in journal)
Authors
Raup, D. M.
(Chicago, University IL, United States)
Date Acquired
August 12, 2013
Publication Date
March 28, 1986
Publication Information
Publication: Science
Volume: 231
ISSN: 0036-8075
Subject Category
LIFE SCIENCES (GENERAL)
Funding Number(s)
CONTRACT_GRANT: NAG2-237
Distribution Limits
Public
Copyright
Other