This page allows for the on-line reproduction of the figures in the paper: Lobry, J.R. (2004) Life history traits and genome structure: aerobiosis and G+C content in bacteria. Lecture Notes in Computer Sciences, 3039:679-686. [ PDF]
Abstract: Evolution is a tinkerer not an engineer: the term exaptation was coined to signify that old structures, that could be not significant in terms of fitness, get re-used when environmental conditions changed. Here I show that the average protein composition of G+C rich bacteria were exapted to the switch from anaerobic to aerobic conditions about 2 billions years ago. Because the proteome composition is under the strong control of directional mutation pressure, this is an example of exaptation at the molecular level for which the underlying mechanism is documented.
Note: Figure 1 is not a true reproduction since clicking on the "do it again" button re-draws the figure from the very last available data. The last figure about the linear geologic time scale was not in the paper but just in my talk, no extra charges, but not automatically updated: based upon ICS 2004 data with USGS color code (there's an alternative color code but it's ugly as far as Archean Eras are concerned).