10 Reasons Why Humans May Not Have Come From Earth

Evolution generally means that a species adapts to its environment, but we don't seem to want to play that game.

A big part of the theory comes down to the fact that we have altered the planet to fit us, rather than the other way around; we just can't seem to bear living in the natural world. The fact that we have altered our environment so drastically makes it seem as though we're just not suited to living in earth's natural habitat.

In fact, what we're doing appears not to be evolving, so much as terraforming.

Another of Silver's arguments is that we're seemingly terrible at reading our own planet. Many animals have built-in sensors for natural phenomena such as earthquakes, tsunamis and even just the ability to predict the weather, whereas we have had to intervene with our technology in order to keep up with them. 

It could be that we came from a planet that is not so geologically active, meaning that there would be no benefit for us to be able to predict earthquakes.

Then, we have the fact that we can't eat most of the food on this planet without altering it in some way. Whether it's by cooking it, or through selective breeding, most of the food that we eat is not as nature intended it. 

We're not saying that our home planet had hamburger trees and rivers of lemonade (if it does then book us a one-way ticket to Alpha Centauri), but that fact that most animals, apart from us, are perfectly fine eating grass and raw zebra is a bit weird.