A Puzzle for the Autumnal Equinox
Every now and then you come across a scientific hypothesis that is so elegant and powerful in its ability to explain that it just feels right. Yet that doesn't automatically make it right. Even when an elegant hypothesis gets support from experiments, it's not time to declare victory. This is especially true in biology, where causes and effects are all gloriously tangled up with one another. It can take a long time to undo the tangle, and hacking away at it, Gordian-style, won't help get to the answer any faster.
Is the colour of autumn leaves really an adaptation? I'm sceptical too.