|LC control no.||sh2009010754
|Topical heading||Mass extinctions
|See also||Extinction (Biology)
|Found in||Work cat.: Mass extinctions : processes and evidence, 1989.
New world encyclopedia, Dec. 9, 2009, via WWW (A mass extinction or extinction event is the phenomenon in which a large number of species of life on Earth become extinct in a relatively short period of time; "mass extinction" refers to an extinction affecting a great many different groups of organisms occupying diverse and wide-spread environments)
Encyclopedia of evolution (Oxford), online, Dec. 9, 2009 (Mass Extinctions: A mass extinction is an extinction of a significant proportion of the world's biota in a geologically brief period of time)
Dict. of biology, (Oxford), online, Dec. 9, 2009 (mass extinction: The extinction of a large number of species within a relatively short interval of the geological time scale)
Wikipedia, Dec. 9, 2009 "Extinction event" entry (Mass extinctions affect most major taxonomic groups present at the time - - birds, mammals, reptiles, ... )