The following is an excerpt from The God Delusion by Richard Dawkins describing the probability of the origin of life versus the probability of the evolution of life:

The origin of life only had to happen once. We therefore can allow it to have been an extremely improbable event, many orders of magnitude more improbable than most people realize, as I shall show. Subsequent evolutionary steps are duplicated, in more or less similar ways, throughout millions and millions of species independently, and continually and repeatedly throughout geological time. Therefore, to explain the evolution of complex life, we cannot resort to the same kind of statistical reasoning as we are able to apply to the origin of life. The events that constitute run-of-the-mill evolution, as distinct from its singular origin (and perhaps a few special cases), cannot have been very improbable.

Learn more about Richard Dawkins here.

Donate to The Richard Dawkins Foundation For Reason And Science here.