Then 1 billion years ago, 3.5 billion after the formation of the Earth, life comes up with a brilliant invention - sex. Evolution accelerates through the more varied genetic combinations that sexual reproduction involves. It still takes another 600 million years, however, to get life onto land - first plants, then insects, and finally amphibians. Most of what we usually think of as geological prehistory - the age of the dinosaurs, the formation of coal, the creation of present day mountain ranges, etc. The details for this time period are rich, and in many cases fascinating.
Continents shuffle around, species rise and fall, and even the cosmos gets into the act.
Then 67 million years ago, a similar event put an end to the age of dinosaurs. To get to anything of more directly human interest, we have to look very recently indeed. The first species to get classified as fully human, Homo habilis, didn't come for another 3 million years, or about 2 million years ago. Let me describe a few that I hear. First, change and evolution are a basic part of existence, even on its largest scales.