God created the universe with laws (gravity, time, etc.) by which it operates; we are able to understand these laws and make discoveries about past and future events and phenomena, including evolution. Evolution is simply a scientific understanding of our origins. It does not make God unnecessary. However, it may mean we need to reevaluate Him and our place in the universe. Evolution may imply that the universe is bigger and more complex than we at first imagined.
Most scientists do not have an agenda of disproving the existence of God through evolution. Rather, they have a fascination with our universe and sincere desire to expand man's knowledge. As scientists learn more, many are impressed that the cosmos could only have been designed by an infinite intelligence. For example, our universe would not be stable unless its initial matter, energy, and space had been precisely balanced. Also, if the nuclear force between protons were only slightly stronger, all the initial hydrogen in the universe would have turned into helium, preventing the subsequent formation of stable, long-lived stars capable of supporting the evolution of life. Marek Demianski, a cosmologist, concludes, "Somebody [God] had to tune [the universe] very precisely."
Evolution is greatly supported by science and accepted by most scientists. In addition to an extensive fossil record dating billions of years, mutations can cause animals to become better adapted to their environment. Consequently, scientists have even observed evolution on a small scale. Also, genetics closely links living species in accordance with evolutionary theory. One popular argument against evolution states that the cell is too complex to have evolved. However, if it is so complex, how can we say it did not evolve? The universe is indeed extremely complex. Besides a large-scale structure of over 100 billion galaxies, there are on the order of 10^25 molecules in a large glass of water, and the approximately 100 elements can combine in almost infinite ways. To proclaim that evolution could not have occurred, based on biomolecular arguments, is extremely speculative.
God is alive and working in the world today. He does miracles (often healings) and we can communicate with Him. He is opposing and will ultimately defeat the powers of darkness, who are exhausting the privileges He originally granted them. (These "supernatural" evil spirits - Satan and his angels - predate the "natural" material universe and are responsible for its perversion and perhaps very existence.) God is all powerful. Nevertheless, He rarely makes major redirections of the natural laws under which He created the universe. He doesn't pick up a volcano and move it somewhere else before it explodes. He doesn't broadcast from Heaven on international TV and say He has decided to remove the AIDS virus from Earth. He doesn't miraculously cause mosquitoes to become extinct in order to eradicate malaria. He doesn't transform all human races into one, alleviating racial tensions.
Hence it is unlikely that our existence is the result of some major redirection of the natural history of this planet by God. For instance, God probably did not miraculously cause the Neanderthals to become extinct and then create a "perfect" Adam and Eve in a "perfect" Garden of Eden, or some equally unlikely scenario. Also it was probably not necessary for God to miraculously put together the first cell -- like a tinker toy -- apart from the cell naturally developing (evolving) under His natural physical laws. And it is unlikely God created the universe 6,000 years ago and made it look billions of years old.
We know that almost everything is changing from existing forms, according to physical laws. The whole universe is expanding and increasing in entropy. Galaxies are evolving and sometimes collide with one another. Stars are being born, evolve, and die. The Earth is slowing down as it spins, and mountains are rising and falling on its surface. Man's population and knowledge are increasing, etc. Is it not also reasonable to suppose that life is changing and developing according to physical laws?
One can accept the conclusion that life, including man, evolved on this planet, or one can come up with all kinds of convoluted explanations to the contrary (including complex and sophisticated scientific arguments). However, God is not contrary to reason, and He is interested in truth and relationship with Him. He wishes us to grow in our understanding of Him and the functioning of His creation, including science and evolution. Belief in Him does not depend on the acceptance of an inerrant Bible and Adam and Eve.