What's In A Name?

I'm proofreading a book on Oceanography. I love doing this stuff because you learn inane bits of trivia that make you much more interesting than you really are at random parties. For instance...

Early Mediterranean cultures envisioned that marginal bodies of water similar to the Mediterranean Sea surrounded most of the continents. The name “Earth” describes the portion of the planet that is inhabited by man in spite of the fact that the majority of the planet’s surface is covered by water. Our planet was named before ocean exploration began.

Which says to me that if fish had developed the ability to talk before they could walk, the third rock from the Sun would be called Water and perhaps Mars would be Earth. And they would've all drowned before evolving onto land due to an inability to keep their mouths shut. Oh wait...