Deep Time in Perspective: An Animated Fossil Hominin Timeline

Abstract

The lapse of deep, geologic time—a concept that Darwin struggled to explain to readers of Origin of Species—is all but ignored in paper representations of hominin evolution. Representational constraints inherent to books and journals may influence how hominin evolution is reconstructed. In an attempt to help overcome these issues, we created an alternative to the traditional phylogenetic diagram. First, in 2005, we built a database of nearly every significant fossil hominin discovery up until about 40,000 years ago. Then we animated a timeline of hominin evolution. The clock starts at 6.5 Ma with the Sahelanthropus tchadensis cranium. Time ticks by on the screen at the chosen rate until 6 Ma when symbols representing the Orrorin tugenensis specimens flash into view, and so on until the proliferation of anatomically modern humans in the Late Pleistocene. Our animated timeline provides a new way to experience deep time. Watching the movie with a generation of 20 years represented by one second takes over 90 hours, and it is difficult to interpret the resulting representation as a bush, or even as a tree, as is presently common.