Speciation, in evolutionary biology, is the splitting of a species into two different sub-species that cannot interbreed; it is one of the engines powering evolution. One mechanism responsible for this is the appearance of a physical barrier that cuts part of the species off from the rest, as when tectonic activity creates an insurmountable rift or mountain range, or an island breaks off from the mainland. The creatures on either side of the barrier evolve independently, resulting in such wonders as the dwarf elephants that used to exist on mediterranean islands, or the diverse finch species of the Galapagos.

During my recent visit to Berlin I was amused to see the same phenomenon, of sorts, happen to man-made objects – namely, pedestrian traffic lights.

Pedestrian crossing Walk/Don’t walk signals vary between countries, but in each country they usually have one standard design. In Europe they usually follow the European standard of a red standing man and a green walking man.
Now this is also the case in Berlin, except that there they have two designs. In West Berlin, the little men are skinny and utilitarian; but in East Berlin they are stylized, chubby and humorous: the famous Ampelmännchen.

Berlin walk signals

The Ampelmann design was developed in the GDR in 1961, and was used in East Germany while the barrier of the Iron Curtain prevented design standardization with the West. When the Berlin Wall became history, the citizens of that fascinating city had two different signal types; for a while you could tell which part of town you’re in by observing the one in use.

And when a barrier comes down and the two species mix again, it is possible for one to wipe out the other. In Berlin, there were plans to replace the Ampelmann with the EU standard of the skinny, businesslike version. Fortunately this planned extinction of the eastern variety met with a public outcry, and now the funny man in the hat is a protected species; in fact I heard they plan to replace the western version with Ampelmännchen, since they’ve become a kind of city mascot. In one pedestrian crossing I even saw the two little men – East and West – eyeing each other uneasily across the street…