Canis Lupus is right on point here. We
did not evolve from monkeys.
Anyway, here is the mechanism by which evolution can cause drastic changes over long time periods. I take the example of a very simple living thing to start with, Pelagibacter ubique. Photo:
http://www.fomosplanejados.com.br/img/assuntos/imagens/60/71.jpg
Pelagibacter ubique has got 1,354 genes in total. Now let's say that one of these guys replicates and makes a mistake in copying on those genes. We now got a new Pelagibacter ubique with 1353 genes that are an exact copy of the parent's genes, and one new one.
Okay, now let's suppose that in this case, the gene mutation was of benefit to Pelagibacter ubique and causes it to use less nitrogen, a hard to acquire resource for this little guy. Now the chances of this slightly mutated being surviving are increased.* The chances of it gaining enough food to reproduce are also increased. Some generations down the line, quite a few more of these Pelagibacter ubique with the one modified gene exist. Many thousands of generations later, they may have out-competed previous versions of Pelagibacter ubique and so Pelagibacter ubique may have two versions now, the original and the one which uses less nitrogen. In this case, we have divergence and over time, perhaps they may drift apart even further. In other cases, perhaps the original Pelagibacter ubique will be totally out-competed and become extinct. Anyway...
Many more generations pass and now one of those guys with the already modified gene has a mutation in another gene, this time allowing it to make a stronger cell wall, without using an extra energy. Great! This guy thrives too. Many thousands of generations later... We have another thriving Pelagibacter ubique with 2 modified genomes, that's 2/1354 we've changed so far...
...And as the millions upon millions of generations pass, more and more genes are modified. Some are also taken away, some new ones added. A million generations down the line, it's not even Pelagibacter ubique anymore, it's an entirely different species!
That is how all evolution happens.
*Conversely, any bad changes to the genome make the creature less likely to pass the gene on to offspring.
Anyway Nathan, I hope this makes you at least think about evolution in a new light. Nothing in the bible actually forbids evolution and everything in the world and the lab supports it. If you must put the action of evolutions existence down to god, at least give god the right to have made things a little more interesting; to allow things to evolve, so that he may look down on an ever changing world.