I am always amazed when people reject something that they don't want to believe. If your entire basis for believe in a god is that evolution couldn't have happened, then you should at least check to make sure that evolution hasn't been proven in the lab. And that is exactly what we find: evolution has been observed under experimental conditions in the lab. There can be no question. We can never go back to a world where it is intellectually honest to question whether evolution is real or not.
Richard E. Lenski at Michigan State University has been running an experiment to watch how bacteria evolve. He started with a single E. coli bacteria and used its descendants to start twelve different laboratory populations. He then watched these bacteria change over time.
But sometime around the 31,500th generation, something dramatic happened in just one of the populations - the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use.
Indeed, the inability to use citrate is one of the traits by which bacteriologists distinguish E. coli from other species. The citrate-using mutants increased in population size and diversity.
"It's the most profound change we have seen during the experiment. This was clearly something quite different for them, and it's outside what was normally considered the bounds of E. coli as a species, which makes it especially interesting," says Lenski.
This is a perfect example of evolution. A population changes over time through reproduction to live better in their environment. This is exactly what the E. coli bacteria did, and because it was observed in a lab, there are samples saved from every stage so that we can go back and rerun the experiment and see exactly what is happening.
Now I know that some creationists will claim that this is an example of micro-evolution. And while they believe in micro-evolution, they don't believe in macro-evolution. But the only difference in micro-evolution and macro-evolution is time. Macro-evolution is simply multiple different micro-evolution events stacked on top of each other.
It might be difficult to imagine the time frames involved in evolving something from a bacteria to a more complex (notice that I didn't say advanced) form of life.
Let's say that we put a marker in our back yard. For every year of time that passes, we are going to measure off a half inch. How long did it take for the E. coli bacteria to evolve to a different form of bacteria? About 20 years, or 10 inches by our scale. How long has life been here on Earth? Using our same scale it would be the entire distance around the Earth. Over that length of time, it is difficult to imagine that much more complex forms of life wouldn't evolve.