Biology used to be about plants, animals, and insects, but five great revolutions have changed the way scientists think about Life. There are signs that a sixth is on its way: mathematics.

The first five revolutions were the invention of the microscope, the systematic classification of the planet's living creatures, evolution, the discovery of the gene, and the structure of DNA. Together, they led biologists ever deeper into the internal workings of living creatures on the smallest scales. Of course there were many other major...