[killerswan]

Probably: our relatives ate them all! There's basically no corner of our planet, from the hottest volcanic ocean vent to the coldest ice at the poles, to the highest clouds in the air, where our relatives don't live.

Of course, it has taken us about 1/4 the lifetime of the entire universe to get this far, so YMMV. :D

[derekp7]

The reason I don't buy that line of reasoning is: The Lions eat the Gazelles, yet there are still Gazelles out there. Also, Gazelles and Zebras share the same land, and one hasn't starved the other of resources. And I don't think that is is just because they came from the same single-celled ancestors that make them able to share the same space. In the same way, I would expect other independent biogenesis lifeforms to still be represented (or new ones popping up periodically).