Shimrod,

The first statement was from Steve Shaw.

Forgetting the questionable theory that "land animals without endoskeletons are restricted in size."

Assuming intelligent design as a possibility. It is equally valid to say "Animals evolved the way they are because of gravity." and "Animals were created the way they are because of gravity" Speculation about gravity does not settle the debate in any way or settle the debate.

The only thing you are saying is that the animals that exist today are subject due to limitations due to gravity.

In any given ecological niche, obviously there is a "sweet spot" in size and shape for any given animal. Accord to Steve's "endoskeleton" theory a land crab would be a much less efficient scavenger on land than say a rat. So if rats are introduced to places where the principle scavenger is crabs, then you are likely to see the crabs decrease in number.

Not sure what Steve is saying about endo skeletons per se. But it seems likely that without competition, animals without more efficient competitors are likely to become larger and slower, with the Moa and the Great Auk as modern examples.