A frequent theme of Desert Diary is the misleading nature of common names, often linking together species not at all closely related. An outstanding example is the widespread habit of using the name Antelope for the North American Pronghorn. In reality, of course, Pronghorns and antelopes aren't at all closely related, being placed in different families or subfamilies, and antelopes being limited to the Old World.
But sometimes, scientists have problems, too, thanks to convergent
evolution. When two groups adapt to the same way of life, this often includes their
bodies becoming much more alike. Sometimes when these body types converge strongly, it
becomes so misleading as to fool biologists into thinking that the similarities mean
close relationship. A case in point concerns the Old World and New World vultures. Both
were long considered members of the Falconiformes, the order that includes eagles,
hawks, and falcons. Only recently has enough evidence accumulated to show that the Old
World vultures are indeed falconiforms, but the New World vultures are actually most
closely related to—of all things—storks.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.