Two laboratories at Penn State set out to show how an obscure undersea microbe metabolizes carbon monoxide into methane and vinegar. What they found was not merely a previously unknown biochemical process -- their discovery also became the inspiration for a fundamental new theory of the origin of life on Earth, reconciling a long-contentious pair of prevailing theories. This new, "thermodynamic" theory of evolution improves upon both previous theories by proposing a central role for energy conservation during early evolution, based on a simple three-step biochemical mechanism.