This was linked on Skepchick this morning: The Science Tattoo Emporium. Check out the 18 pages of amazing science-themed body art. Here are some of the evolution ones.
"Origin of an Epidemic" illustrates the owner's graduate research on the evolutionary history of the HIV virus. This is definitely my favorite of the bunch.
Darwin's finches, based on Darwin's first published drawings.
"Five Kingdoms" is a cladogram depicting the five major groupings of living organisms: Monera, Protista, Plantae, Fungi, and Animalia. The sea dragon is especially beautiful.
The very first phylogenetic tree, from Darwin's notebook.
And another Tree of Life, based on the drawing by Ernst Haeckel.