Why do many atheists base Darwinism as their argument against God and creationism?

Because they are deceived.

I do not think that many atheists do base their atheism on evolution. We generally base it on the lack of evidence for any god.

"If we had all come from one cell that evolved into everything, there would still only be one form of life. That form of life wouldn't need to change because the environment couldn't change."

Yes, it would. There would still have been different conditions in different locations, and as life reproduced that itself would change the environment.

"There would be no genes because they wouldn't be needed, the life forms would be hermaphrodite cannibals."

By evolving a defence against such cannibals, an organism would increase its chances of reproduction, so there would be a need for genes.

"Maurog, this is exactly what evolution has to be- not a theory."

What? Do you know what a theory is, in the scientific sense?

"Without witness or proof of DNA mutations in action it can only be a theory."

Scientists HAVE witnessed DNA mutations. The words "only be a theory" indicate that you clearly do not know what a theory is in the scientific sense, and you seem to be ignorant of science generally. You need to know what you are talking about if you expect to be taken seriously.

I can't explain it without confusing you, I'm not a biologist. Just.. for the love of God... go to a science lesson, please. And DNA changes is bacteria all the time, so there's plenty of evidence. If you say otherwise, that's ignoring evidence and that's what I find most devout believers do. I've spent too much time arguing with people like you, and I'd rather you stopped disputing fact and kept your ideas to yourself.

If a life form mutates and this mutation gives it an advantage over others, it will out breed them and eventually replace them. Then another one might mutate with a better evolutionary trait, and outgrow them. This happens millions of times in different areas of the world, and you get animal variation. For example, a shark has adapted to hunt in warm oceans, whereas a bird has evolved to fly and catch insect.

If you don't understand this, watch a video. And if you still don't understand you have a mental barrier formed by your religion and you need to crush it.

It all started with simple, self replicating RNA, which they've been able to make out of chemicals in a lab now soooo.... Yeah. From there it's simple, plant life was first, which as you know, does not need a "food" source, merely energy. They've proven that mutations occur as cells divide. The only part of theory you could argue with is to say that beneficial mutations don't make things live longer, which would be like saying a slower gazele would survive longer when chased by lions, it's madness.

I had my revelation that I did not believe in god in my early teens. It was not based on Evolution (xDarwinismx). Secondly, if you want to talk on this subject and be taken seriously I suggest you study the subject so you have some idea what you are talking about.

My suggested reading would be "The Greatest Show On Earth" by Richard Dawkins, as it's a much less intimidating read than "On The Origin Of Species" by Charles Darwin.

You might have missed this but over the last 4bn years there have been quite a few changes in the environment.

Even if it hadn't evolution would still work to produce something even better adapted for the environment. Intestinal bacteria are perfectly well designed to live in your stomach, that didn't stop tapeworms evolving.

Atheists rely on Darwin because his theory is a popular example, and one that highlights a fundamental disagreement between (most) of religion's adherents and atheists. They disagree not specifically on evolution, but instead on what counts as authority with respect to knowledge.

The author of one's knowledge is extremely important to identify, because to take a single source of knowledge as paramount is to accede to that source as a power over one's life. For atheists, science, peer review, and one's own senses are valid sources of knowledge. For many religious adherents, religious texts, clergy, and revelation are the only valid sources.

Wherever two people disagree over what counts as the proper authority, they engage in a bitter dispute over power. Atheists recognize this and use Darwinism to point out that a majority of adherents only believe in scientific findings only if their religion tells them those findings are valid. Your own protestations against evolutionary theory only support their point.

This is not true as such. Though Darwin was an advanced soul he started far too late with earth's history the same as with Genesis bible texts.

They missed out two previous generations of beings that were the forerunners of present day humanity.

So one must seek for more data in esoteric books etc.

Firstly, you are completely wrong.

Secondly, even if evolution were wrong I'd still be an Atheist

Thirdly, we don't use evolution to support our Atheism, just some dumb Christians attack it and usually without any understanding of what it is all about.

Do you realise you're defending an ancient myth over scientific proof? Evolution is a proven fact, it's not my fault you haven't bothered to look at the evidence. I'm an atheist, not a scientist.

Have you ever heard of the Oxygen Catastrophe? If not, I suggest you read up on it, because that is the very reason there are animals, not just plants. Once again, logic,reason and fact reign supreme.