“Our only real competition for domination of the planet remains the viruses,” the microbiologist Joshua Lederberg once said. “The survival of humanit… - Jonathan Weiner

Philosophers used to ask whether we are born with or invent our sense of time. Now we know that we have clocks woven into every one of our cells. Philosophers also used to ask how we know that the sun will rise tomorrow. In a sense we have that answer built into us, too. The clock is a kind of orrery in the heart of every one of our cells, revolving to help us keep time with our world, a model of the cosmos inside our heads that cycles whether we are in or out of sight of the sun. The revolution of the stars and the seasons is written in the turns of our DNA.

With the discovery of the clock gene, the sense of time, mysterious for so many centuries, was no longer a mystery that could be observed only from the outside. Now it could be explored as a mechanism from the inside. The discovery implied that behavior itself could now be charted and mapped as precisely as any other aspect of inheritance. Qualities that people had always thought of as somehow floating above the body, apart from the body, as if they belonged to the realm of the spirit and not of the flesh, as if they were supernatural, might be mapped right alongside qualities as mundane as eye pigment.

Taken together, these new studies suggest that Darwin did not know the strength of his own theory. He vastly underestimated the power of natural selection. Its action is neither rare nor slow. It leads to evolution daily and hourly, all around us, and we can watch.