Thursday, June 6, 2013 6:37:53 PM
Insects wouldn't grow fantastically large, they would evolve into larger versions, I process that would take eons. Also, be consistent, don`t count oxygen bounded to other elements in the first example and ignore it in the second one. It would take a lot more than five seconds to sunburn, even without an ozone layer. Earth had no atmospheric oxygen for billions of years.