In thinking some more about the controversy between ID and evolution, it occurred to me that evolution, as a description of something that happens to us (that is, we species) physically, is not a particularly bad metaphor for something that happens to us (that is, we individual body/soul entities) spiritually.
A biological species is an interesting metaphysical entity in some ways. There is a fair amount of controversy among philosophers of biology as to what is the best way to view the concept of biological species--are they individuals, groups, mere heaps, nothing at all--but intuitively at least I think that, when it comes to a biological species, most folks are like Supreme Court Justices looking at pornography: they know it when they see it. A species incorporates in itself all the information that is also distributed severally among the individual members of the species. Through time the species as a whole adapts or fails to adapt to the various aspects of the environment (physical and cultural) that apply selection pressure to the genome. If the species fails to adapt adequately, it may be driven to exstinction. That is, a time may come when that species fails to exist. Unless you are the most spectacularly out of touch fundie literalist, you think that this is exactly what happened to some of the dinosaurs, while others of them adapted over and over until now they are unrecognizable as dinosaurs because, well, they no longer are dinosaurs.
A species adapts or fails to adapt in the form of its individual instantiations, the particulars that constitute the species. Some die, some do not, those that manage to reproduce before dying pass on their genetic information to another generation. Those that reproduce more than others give their genetic information a kind of advantage in the gene pool, as it were. An individual human being is, of course, also a member of a biological species. An individual human being can die without leaving any offspring and the species will continue. At least for a while--who knows how long they can keep this up in Europe. But anyway. There is something about each individual human that does not die with its body: the soul is immortal, at least in principle. But that does not entail that it cannot "adapt" in its own way.
Each time we sin, we turn away from God, and because God is life, we also turn away from life, from our own survival. Dying, decay, and death are all physical signs of our fallen nature precisely because to fall is to reject life and bring upon oneself the consequences of that rejection. Just as the man who refuses to take a curing medicine will eventually die, so too the man who continually refuses to accept God's will also, eventually, will die.
To refuse to accept God's will, to turn away from life and towards dying, decay, and death, is not a very "adapted" way to "live", since the person who lives life that way is rather like a species that is fully unadapted to its environment. We were intended for life with God, but when we turn from that life we choose to live in the toxic environment of our own concupiscence.
How can we "adapt" our souls and, as the heliotrope turns its face towards the sun, turn our wills towards God? The Sacrament of Reconciliation. Each time we repent, amend our lives, confess our sins and receive Sacramental Absolution, our souls are healed of the damage done them by turning away from God, giving us a new lease on life, just as a species can survive by adapting to the structure of its environment. The difference, of course, is that each of us has only one soul, but that soul does die, if only a little, each time we sin. If we do not repent before our time is up, our soul may become like the Tyrannosaur. But if we do adapt through Confession and amendment of life, we may survive for eternity.
The similarity to biological evolution lies in the notion of change. A species cannot adapt without changing in some way. Either the expressed phenotypes must be different or the genome itself must be modified. So, too, we cannot amend our lives without changing something about us that has gone awry. The New Testament Greek word for repentance is metanoia, literally a "changing of one's mind": to repent of our sins we must make something different about ourselves, and that change will, with God's help, enable us to survive.
We are people of the Incarnation--in our experience the physical and the spiritual are inextricably linked. That is why we have the Sacraments, and that is why it is not really all that surprising to find that an extremely important aspect of the physical world--adaptation by natural selection--is isomorphic with an even more important aspect of the spiritual world.