Aristotle, Physics, Book II Chapter 8:
Why not suppose, then, that the same is true of the parts of natural organisms? On this view, it is of necessity that, for example, the front teeth grow sharp and well adapted for biting, and the back ones broad and useful for chewing food; this useful result was coincidental, not what they were for. The same will be true of all the other parts that seem to be for something. On this view, then, whenever all the parts came about coincidentally as though they were for something, these animals survived, since their constitution, though coming about by chance, made them suitable for survival. Other animals, however, were differently constituted and so were destroyed; indeed they are still being destroyed, as Empedocles says of the man-headed calves.Hey, Darwin anticipated! Wait...
This argument, then, and others like it, might puzzle someone. In fact, however, it is impossible for things to be like this.Never mind. It is sort of fanciful. But hey, that final cause theory seems to work pretty well.
Btw, Empedocles is even more awesome than this makes him sound.