The question seems not only absurd, but also to work against the position I have staked out in this blog over many months. On the view I have defended, Evolutionary Theory (ET) is a theory whose application is restricted to a particular domain, namely, the domain of the material and the empirically verifiable; theology is not so restricted, and so the utility of ET to theology seems to be very low, if not zero.
There's certainly no need to convince the working evolutionary biologist of such a possible utility: what the working biologist has to say about theology, qua biologist, is irrelevant--indeed, meaningless. Nor is there any particularly compelling reason to convince the orthodox (small "o") theologian of such a possible utility, because the orthodox theologian already knows that materialist, empirical theories have nothing to say about, and no ramifications related to, theology. This is why, in fact, no orthodox theologian is worried about the question whether Christianity is compatible with ET, for he already knows that they are as compatible with each other as Euclidian geometry, qua geometry, is compatible with musical composition, qua musical composition: the disciplines do not impinge on each other in any way.
So what possible utility could ET have for theology, and to whom are we addressing this argument? ET is a theory about certain forms of material beings and how they relate to each other as individuals and in populations situated in certain environments. It is one of the most robustly confirmed scientific theories in history and serves, if anything does, as a paradigm case of the importance of human reasoning in understanding human nature as such. But all scientists and philosophers of science know that it is open to revision: if and when new empirical evidence should prove to be incompatible with the theory as it stands, the theory will be revised appropriately. This is not a threatening fact to the scientist or the philosopher of science, it is further proof of the value of scientific investigation and, hence, a motivation to keep doing scientific research. (In this regard it is somewhat strange that writers like Richard Dawkins write about ET as "an established fact". Established facts, whatever else they may be, are not open to revision, otherwise they would not be established facts. No scientific theory is "an established fact" in the sense of not being open to revision, though it is, of course, quite true to say that ET is well confirmed. It would be a mistake, however, to conflate the notions of confirmation and facticity.)
That scientific research is a hallmark of the human mind and an expression of the human essential nature is one reason to think that ET has some value to theology, since it is a fact that is not merely consistent with but appears to follow from what theology claims about human nature; but it is not something that is unique to ET. Any robustly confirmed scientific theory can claim an equal utility for theology. ET, however, has a unique value that is not shared by any other scientific theory. ET is essentially a theory about change, and more specifically it is a theory about change that is due to variation. Where there is no variation, evolution by means of natural selection cannot take place (drift would still be possible, of course, but that would be true even if ET were false). A necessary precondition on variation is, of course, difference. Indeed, variation is arguably just another term for difference. Without getting overly Parmenidean about it, we may also say, somewhat loosely, that difference is a kind of opposition: a property p is said to be different from any property that is ~p and, according to the Law of Concontradiction, ~(p & ~p). This is an ontological as well as a logical claim: just as the two propositions, p and ~p, cannot be true at the same time and in the same respect, the state of affairs cannot be in two orthogonal states at the same time and in the same respect (according to ET; according to quantum mechanics this may not be the case; whether the consistency of ET with quantum mechanics is more of a problem for ET than for QM is a question for another context, but it certainly underscores what I said earlier about the revisability of scientific theories).
The fallen world in which we live is, from a theological point of view, above all a world of oppositions: opposition to God, opposition to one another, even, in a sense, opposition to ourselves (I want to resist sin, but because of weakness sometimes I cannot). To move from sin to grace is to make a change that is, in a certain extended sense, adaptive. Sin is, by definition, a willful turning away from God; by God's grace we are given the capacity to turn back to him, and doing so is as salutary as adapting to the environment in which we live. Every time I turn away from God, every time I sin, I die a little (sometimes, completely), but through Reconciliation I am given another "generation", as it were, another seed to plant in the environment in which I live to nurture and train to grow towards God rather than away from him. If I learn anything from my sin and reconciliation, it is rather like an adaptive change in a genome that did not survive in a previous setting. Without opposition, without variation, none of this would be possible ("O happy fault, O necessary sin of Adam, that gained for us such a Redeemer"). Life before the fall was, in a certain sense, a static sort of life in the sense that Adam and Eve had not yet sinned, there was not yet any opposition to God, to each other, or within themselves; in the eschaton life will again be static: as the Talking Heads once said, "Heaven is a place where nothing ever happens". All will be one at that time, and the Sacraments, including Reconciliation, will pass away. Only here, in this world, are the Sacraments necessary and good, and although ET does not explain anything about our relations to God or one another (since it is not a theological but a materialist explanatory account aimed not at theological truth but empirical truth), nevertheless by its very truth it illustrates something deeply true and important about the very fabric of being itself as we experience it. It is, in short, a sacramentally sound description of the way things are in addition to being empirically verifiable.
In my opinion, this will be true of any robustly verifiable scientific theory, precisely because every such theory, if accurately representing they way things are to any significant degree, will be consistent with the theological truths about how things are. But ET seems to play a special role in this illustrative sense, since it paints a very vivid picture of what "survival of the fittest" means when translated into "survival of the most grace-filled". By the way in which natural processes play themselves out at the level of merely material beings, we see writ large the far more important way in which our spiritual survival is tied to adapting our own wills to the will of God by means of a sequence of generations of reconciliation. That God would use perceptual evidence--evidence at the materialist, empirical level--to communicate to us this great truth is not in the least alien to our theology, since the core of our faith was made known to us empirically, by means of the life of Our Lord and the eyewitnesses who have made known to us the facts and meaning of that life.
So my claim here is aimed principally at those who fear that ET represents some sort of a threat to Christian truth, or that it raises difficulties for Christian theology. Far from doing that, it is fully consistent with that theology and, indeed, serves to illustrate certain very important aspects of it. I have argued elsewhere that it even serves quite well as an answer to the so-called "problem of evil", since it makes suffering, death, and dying all perfectly natural processes that are in fact valuable elements of any evolutionary story of the origins and development of life, just as, theologically, suffering and death are turned by God into ways of growing closer to him and experiencing first hand what it means to abandon oneself to him. This is a message that will be of no interest to the biologist qua biologist (though it may interest the biologist who happens to be a Christian), and no news to the theologian. Perhaps it will be of service to nobody in particular. In fact, I hope that is the case, if what it means is that everybody already knew it to be true. But for those who were still worried about ET, it may perhaps serve as some sort of palliative.