The point the book makes is a valid one, though. The Europeans didn't wipe out their American competition through military force, after all. They had biological superiority based on years of living with domesticated animals in crowded urban environments.
And native americans didn't live "close" to nature? C'mon.
There was no biological superiority. It was just good/bad luck that a germ they weren't ready for jumped. It might as well gone the other way around.
*SNIPPED PARAGRAPH*
Interesting vision of a future space battle. However, that creature you're describing?
I wonder what freaky evolution would ever come up with sonmething like that..I consider bumping into my time traveling evil twin more likely.
Oh, and my rant was more directed to large-scale implications (battles) rather than a single marine. In some universe you have races that travel from planet to planet in organic, living ships and wage war (like Zerg, the Tyranids) Now THAT is bull****.
Not to mention that coming up with a silly creature doesn't prove anything. I can come up with rifles that fire miniature black holes, and as such can devour any creature you can come up with. This really is going nowhere.