Yes, pretty much the result of the 5 major (or 9 major) extinction events. I was using this [1] it's a number frequently used when referring to whats been and

Yes, pretty much the result of the 5 major (or 9 major) extinction events. I was using this [1] it's a number frequently used when referring to whats been and whats left. It's really an extraordinary number when thinking about it. [1] http://www.pbs.org/wgbh/evolution/extinction/massext/statement_03.html http://www.pbs.org/wgbh/evolution/extinction/massext/stateme...