No Turning Back
The Life and Death of Animal Species
Extinction (Sort of) Explained
Standard textbooks on evolutionary biology and paleontology
hardly mention extinction. Much is said about the origin of
species and the evolution of species once they are formed, but
discussions of extinction are usually limited to casual references
and the enigma of the great mass extinctions. On causes of extinction
we are apt to read, "Species become extinct when population
sizes drop to zero," or "Species die out if they are unable to
adapt to changing conditions." These statements are true, of
course, but are virtually devoid of content.
-- David Raup, 1991
Everybody knows what extinction is. The dictionary defines it as "the act
of extinguishing, or, the fact of becoming extinguished or extinct." (Extinguish
is in turn defined as "to put out a fire, a light, or to bring an end to.")
More to our point, Thain and Hickman's Penguin Dictionary of Biology
(1996) defines extinction as "Termination of a genealogical lineage. Used
most frequently in ... read full excerpt from: No Turning Back ebook
