There
is a very powerful way that evolution could be falsified. I believe it was actually stated by
Darwin, and has been expanded by
Richard Dawkins in successive books (
The Blind Watchmaker, etc). It relies on the fact that evolution progresses in small, feasible steps. Any structure, system or mechanism that would is so different to previous, more primitive systems that it could not have come about by a relatively low-probability variation would
blow the theory out of the water. Good
anti-darwinians know this and have tried to find examples of this, e.g. the eye. Yet despite the vast portfolio of
nature they have not found a single example that stands up to close examination. Every wonder in nature has a history of simpler ancestors.
There is also a pretty simple way to observe evolution in action, i.e. in simulation.
Thousands of geeks around the world have independently knocked-up evolutionary simulations, based on Darwin's abstract principles of Heredity, Variation and Selection and watched their creations adapt and converge.
Finally, something I don't think many people appreciate, is that a rich and complex environment encourages the development of complex systems which in turn become the backdrop for other systems, reflecting the richness back. This feedback effect drives the explosive complexity that we see happening everywhere; nature, society, computers..