Fig. 9

Some evolutionary trees include information about time and diversity. a shows an example of an evolutionary tree that includes not only information about topology but also time as given in the axis at the left and relative species diversity as indicated by the width of branches. Note that not all branches are of equal length because the tree is scaled to geological time periods and includes lineages that are extinct and therefore do not extend to the present. From Benton (2005), reproduced by permission of Blackwell. b shows an example of an evolutionary tree that provides information about geographical distribution and feeding ecology but that provides only a general indication of evolutionary relationships rather than explicit links between individual species (but see MacFadden 1992). From MacFadden (2005), illustration by P. Huey. Reprinted by permission of the American Association for the Advancement of Science