How did the leopard get it spots?

Biomorphogenesis, the process by which biological forms arise during development, is a fascinating area that crosses many fields, including computer science, mathematics, biology and chemistry. How do the stripes develop on a zebra? Alan Turing, one of the first computer scientists and the man who developed the computational engine that cracked the Enigma code in World War II, took on this problem in the early 1950s. In 1952 he published, "The Chemical Basis of Morphogenesis" [Phil. Trans. R. Soc. London B 1952, 237, 37-72]. He posits in this paper that oscillating chemical reactions, such as the Belousov-Zhabotinsky reaction, could lead to temporal-spatial differences in pigmentation. You can see why this might be the case in this animation of the reaction.

The BZ reaction is complex, the proposed mechanism consists of almost 20 steps - much more complex than those we are discussing in general chemistry this week! You can watch the BZ reaction in this video clip - the color changes look like magic.