RE: Extinct Species
April 2, 2012 at 10:20 am
(This post was last modified: April 2, 2012 at 10:20 am by BoyWonder.)
(April 2, 2012 at 10:11 am)Chuck Wrote:(April 2, 2012 at 8:30 am)Phil Wrote: Considering the average lifetime of a species is 5-10 million years and the first life appeared 3800 million years ago, I have no doubt whatsoever that extinct species are over 99%
The problem with assigning numbers is the concept of "species" is hard to apply to the much of the unicellular world where bacteria liberally swap genes wholesale. Fossil evidence is also very lacking for complex life prior to about 600 million years ago, although DNA evidence puts origin of many of the complex animal phylums at 700-900 million years ago. It's not clear if speciation would be rapid prior to evolution of predation around 540 million yesrs ago. Finally there is reason to think rates of extinction amongst higher land animals were substantially different prior to permian extinction.
You can make it as difficult as you want, and go looking for problems, or you can make it easy: take any 100 million year period you like, any, and look at the extinctions and survivors. That 99% will hold in each and every epoch you care to select.
