[whattajoke]

Up until 4.2 billion years ago, the highest form of life was the amoeba, a one-celled creature.

I don't think amoebae were around that far back. At least there's not fossil record of them AFAIK. The earliest we are aware of date to the Neoprotozoic Era, which dates back "only" half a billion years.

[DavidAccord]

You are right, I meant to say 4.5 -4.2 billion = 300 millions years ago .. approx.