evolution of software

The marketplace is often described in Darwinist terms: products must continually adapt to survive. This is especially true in the software area; even more so for free software.

I think this would make a good PhD subject: Darwinism as applied to software.

Alan Kay and other software experts argue that we must strive to evolve software.

I would say that software development is more Lamarckian than Darwinian, as improvements are usually made with the specific purpose of overcoming specific problems. Genetic algorithms are, of course, an exception.