I am working on some very smart things to say here. Really. Meanwhile, there's 
No, no. This isn't from the tasteless blurb on the cover of a Creationist book. This is about research on the evolution of anus published at Nature Magazine.
"The very simple question is how to get from one opening to two," says Detlev Arendt, a researcher at the European Molecular Biology Laboratory in Heidelberg, Germany. The question may be obvious, but it is not easy to answer. Punching a new hole on the opposite end from the mouth is unlikely from an evolutionary standpoint, says Arendt. So he and others have suggested that over time, the mouth elongated and then separated into a mouth and anus. Once the body included a gut with two ends, the anus could migrate to the far end of animal.Although I am neither an anal biologist nor a (teapot?) topologist, I think this is one area where the intersection of these two subjects is .... is fruitful. If this dirty biology piqued your interest, you should read D' Archy Thompson for the classic and absolutely brilliant tour de force On Growth and Form.
