At the core of all evolutionary systems are genetic algorithms whether they be natural or synthetic, the same principles apply and are found to work as highly effective and autonomous design tools.Computer programs that "evolve" in ways that resemble natural selection can solve complex problems even their creators do not fully understand.
That nature uses more elemental ingredients is of no significance. The process is entirely scalable which is why we see evidence of evolution in a wide variety of different realms. Our own best tool for modelling evolution at the moment is the computer (our latest toy) but we may soon be able to work at the same atomic scale that nature uses and importantly, the transition would be a smooth one.
So given that we have taken a hint from nature and found her methods to be effective at producing such autonomous designs, why would we continue to doubt that this is the very system responsible for all the apparent natural "designs" we see around us? After all, would it not be an incredible coincidence if we had misinterpreted natures methods yet still ended up with a powerfully creative yet autonomous system purely by chance?
Additional material is widely available on the internet, for example:
The Genetic Algorithms Archive (a repository for information related to research in genetic algorithms and other forms of evolutionary computation.)
Genetic Algorithms and Artificial Life Resources
Wikipedias entry for genetic algorithms


