You make some good points, Scott. I certainly don't have any really good answers.

But my main concern, I guess, is making sure that the role we play in relation to any extraterrestrial life that we may ever find isn't commensurate with the role dinosaurs used to play in relation to mammals. That is, as long as dinosaurs were so completely dominant, mammals had no chance to begin to realize their full potential. Perhaps the "full potential" of a Martian or Europan microbe might seem laughably modest, but the same might have been once thought of the tiny, subterranean, bug-eating ancestors of humanity.

If we even land on a planet of microbes--or even somewhat more highly organized life--we'll be the dinsoaurs, making the ground shake and altering their future with every footfall.

I don't have the scientific or biological training to assess whether or not this is even a realistic concern, though. Am I off the deep end here?