A Biological Big Bang

The Cambrian Explosion Becomes More Explosive

New high-resolution age data narrows the date range for the paleon-tological event known as the Ediacaran-Cambrian transition to 410,000 years. A period of 410,000 years seems a long time to most people, but to scientists who study Earth's history and life, it's a mere moment. Discovery of a novel life-form that appeared within such a "moment" in the earliest days of the Cambrian era carries profound implications. When viewed in light of the measured "molecular clock" rate, this new finding presents a serious challenge to the commonly accepted story of life's slow, gradual development by natural processes alone.

Life's Explosion onto the Scene

The Cambrian...