David P. Mindell, of the California Academy of Sciences, wrote a review of the book Evolution Since Darwin: The First 150 Years which appeared in in the journal Science ("At the Sesquicentennial of Origin"; 24 December 2010, page 1747). At the end of this review, Mindell writes that evolution is "the root for natural explanations of human origins ... and ultimate impetus for human moral behavior and values".
To say that evolution is the impetus for morality seems to be true, although still surprising to many of us. How can genetic fluctuation and varied reproductive success be the driving force, the impetus, which brings about cooperation, let alone systems of morality and social and legal judgement? Even among evolutionary scientists, that proposal seemed to stretch credulity until a few decades ago. Now, mathematics, observation, and experiment appear to confirm that the process of evolutionary change not only can but did provide the mechanism which brought such complexity to life. Evolution, it now seems, truly is the "impetus" for moral behavior.
Mindell, though, adds a more questionable qualifier. He writes "ultimate impetus", which sounds very much like "original driving force" or even the "prime mover". That latter is historically a theological term and I mention it specifically to point out how the phrase "ultimate impetus" verges on speculation somewhat removed from evolutionary biology.
Can we not ask what is the impetus for evolution? Depending on your point of view you might suggest, for example, that cosmic rays interacting with molecules of DNA in germ cells is an impetus which brings about evolutionary change. And there is a further driving force behind the cosmic ray. Then in what sense can evolution be an "ultimate impetus"? Logically, a cause which is itself caused is not an ultimate cause. Let's leave the question of ultimacy to the philosophers.
It is better, I think, to use language which clearly names evolution as a process or a mechanism, one through which truly remarkable changes are taking place. It is evolution's role as the proximal mediator of anatomical, physiological, psychological, and even social change which makes evolutionary theory so astonishing.