A good discussion on the thread!
Darwin's materialism and natural selection means the "survival of the fittest," it is the mechanism by which species evolved. Therefore, the elimination of God makes a significant difference. There can be no right or wrong, no higher standard than our desires, and no reason to follow any creed or purples other than self-preservation. However, if there is no soul then there is no essential difference between humans and apes. And there is no reason to expect anyone to act essentially different from apes. What makes the difference is not where the body came from but whether or not there is a soul.
The soul can't evolve. Spirit can't come from matter. You can't get through, consciousness, reason or self-awareness from atoms or molecules. Awareness of the material universe is not one more part of that universe. The knowledge of a thing does not make knowledge one more part of the thing, for knowledge can transcend a thing being an addition from without. Science can say absolutely nothing about where souls come from, for souls cannot be seen or measured.