Originally Posted by aries100
As for the giant insects, I remember a tv show I watched some years back. It is, it seems, all about the amount of oxygen in the air. The more oxygen in the air, the bigger the insects are. That's the explanation given in the tv-show.

Yeah the pre-historic insects supposedly were really large, saw a show about it recently.. Size can also be either advantage or disadvantage in evolution, for insects its probably better to be small (to escape for example birds), if birds died out they'd evolve differently.