Aliens Riding Meteorites: David Dobbs on the Journal of Cosmology

Maybe humans are not native to this planet. Maybe we came from one such meteorite. :)

The article is about fossils found in meteorites that have been on earth for a very long time.

I'm not worried about fossilized bacteria taking over Earth's ecosystem.

"If we find an alien bug via a meteorite, then that bug was one of the reigning champions in terms of ability to survive and subdue its opponents."

That doesn't mean it's some kind of super-bug. The dodo survived long enough and I'd hardly call it a reigning champion. In the bacterial sense, there are plenty of harmless bacteria as well.

The traits that allow something to survive extended periods in space don't automatically grant it the traits that would allow it to thrive on Earth above all else.

Look at Earth's extremophiles, the bacteria that can survive near thermal vents on the ocean floor, extended trips in space/vacuum, intense radiation, sub-zero temps, etc, there's no evidence that they're taking over the non-extreme locations. Even if they do survive outside their "home" environment, that doesn't automatically make them the top dog that will edge out everything else.