What is Extinction?Extinction is the end of a
group of organisms (normally a species).
Extinctions are a normal
part of evolution.
Background Extinction Rate• Average Life Span of a species• About 1 extinction/million species/year• Over 98% of all species ever to live on earth
are now extinct.• How do we measure extinction rates using
fossils?Type of Animal Average Species Life Span
All Fossil Groups .5 - 5 million years
Invertebrate 11 million years
Mammal 1 million years
Mass Extinction: 50% or more of the living species die out suddenly
http://dsc.discovery.com/earth/wide-angle/mass-extinctions-timeline.html
With all this extinction, how do we still have so many species on Earth?
Are we currently in a Mass Extinction?
Some scientists say that up to half of all theorganisms on Earth right now will be extinct by 2100