Re: Oxygen level in Mezoic

[Dinogeorge@aol.com]

In a message dated 8/5/02 2:07:03 PM Pacific Daylight Time, 
dannj@alphalink.com.au writes:

<< We certainly don't see dragonflies with one-foot wingspans anymore, >>

Today these might suffer terribly at the beaks of birds, which might keep 
them from evolving. In the dragonfly heyday, there were no birds or 
pterosaurs to hunt the big ones. Maybe big dragonflies were extinctified by 
competition from/predation by pterosaurs or dino-birds; any idea as to the 
timing of the appearance and disappearance of these groups?.