How do cells know what they should become as the body develops? Biological development depends crucially on spatial patterns: the lines that eventually give rise to segments, organs, or markings like ...

A yellow band across a wing might look like a simple flourish. In the South American rainforest, it can mean survival. Across butterflies and a day-flying moth that split from one another tens of ...

This volume is based on the National Academy of Sciences' Colloquium on the Tempo and Mode of Evolution. The articles appearing in these pages were contributed by speakers at the colloquium and have ...