Not all religious people oppose evolution, but those who do, or those who use evolution as evidence for god, are wrong. With all the evidence from the many different areas of science supporting evolution, it is almost impossible that modern science has it wrong. Darwin's theory of evolution will most likely stand the test of time (and good science).
Today, I'm going to address the specific group which believe in god, believe in evolution, and believe that evolution itself is evidence for god.
The argument often comes as "I understand that the animals and plants were not designed, but doesn't the fact that natural selection and DNA itself is so complex, doesn't this show that a god must have designed the system?".
No, it fucking doesn't.
The argument is a complete non sequitur, the evidence simply doesn't lead to the outcome. The argument is flawed in many ways.
First, just because we don't presently understand precisely how DNA came to be, and how it arranged itself into a self replicating molecule, it doesn't mean science will never know. So until we know, we shouldn't lie to each other and claim we know that it was god that created it all.
Second, there is no other way such a system could exist. The DNA is as complex as it is because if it was any less complex, it wouldn't work, and we wouldn't be alive to marvel at it's randomness. There might be another way life can arise using a similar system to DNA, with a completely different chemical structure, but equally complex, and this could theoretically work. As we now know, there are a few ways to make a light bulb (incandescent, halogen, LED, etc), but as Edison found out, there are many many ways not to make a light bulb.
Thus, any system that was not complex and didn't have the illusion of design, would not be able to give rise to life sophisticated enough to ponder over the system that it arose from.