Darwin was just another man like you and me.I don't believe in the concept of god and atheism is the rejection of god.Religion is a collection of belief systems, and Atheism is, in a broad sense, the rejection of such belief system.
And about monkey turning in to human,that is a process happened over a period of hundreds of thousands of years.So no one has seen it.But their are plenty of genetic and Paleoanthropological evidence suggesting this process happened.It explains that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
One of the earliest defining human traits, bipedalism -- the ability to walk on two legs -- evolved over 4 million years ago. Other important human characteristics -- such as a large and complex brain, the ability to make and use tools, and the capacity for language -- developed more recently. Many advanced traits -- including complex symbolic expression, art, and elaborate cultural diversity -- emerged mainly during the past 100,000 years.
