Evolution is the process that has generated most if not all known complex systems. These are either the direct products of biological evolution: nervous systems, immune systems, ecologies; or the eip-phenomena of biological evolution: culture, language, economies. Thus understanding evolution is important to understanding complex systems. This understanding has been advanced recently by the advent of artificial realities into which natural evolution can be inoculated.
Evolution is an extremely powerful natural force, which given enough time, is capable of spontaneously creating extraordinary complexity out of simple materials. The greatest obstacles to understanding evolution have been that we have had only a single example of evolution available for study (life on earth), and that in this example, evolution is played out over time spans which are very large compared to a scientific career. In spite of these limitations, evolutionary theory has firmly established many basic principles. However, these principles have been established through the logical analysis of the static products of evolution, but without actually observing the process, without experimental test, and without the benefit of comparing completely independent instances of evolution.
Darwin  laid out the core of the currently accepted theory of evolution after the voyage of the Beagle. This voyage gave him the opportunity to observe first hand, the variation of species preserved in the fossil record, and preserved among geographically isolated populations in areas like the Galapagos archipelago. Darwin formulated the elements of the theory that is still the core of evolutionary biology today:
1) Individuals vary in their viability in the environments that they occupy.
2) This variation is heritable.
3) Self-replicating individuals tend to produce more offspring than can survive on the limited resources available in the environment.
4) In the ensuing struggle for survival, the individuals best adapted to the environment are the ones that will survive to reproduce.
As a result of the iteration of this process over many generations, populations of organisms change, generally becoming better adapted to their environment.
Darwin developed this theory without actually observing the process, and without the benefit of experimental test. In this paper I will describe the inoculation of Darwinian evolution into an artificial reality, and describe some of the resultant macro-evolutionary processes: variation in the patterns of evolution in different worlds, the building of increasingly complex structures, and transient reduction of entropy in evolving communities.