One of the most puzzling aspects of the fossil record is the way evolution appears to accelerate as one approaches the present. For the first 4 billion years little happens. In the final 250 million years diversifi- cation rates increase almost exponentially, as exemplified by the history of the flowering plants, ferns, beetles, teleost fish, birds, reptiles, mammals and amphibians (and as illustrated by the two diversity graphs in this section). Part of the explanation may be that the apparent acceleration is an artefact of the decreasing inflation of geological time.