Let me cite a relevant passage from the Daily Press (by James A. Dellavalle):
In spite of the similarity in their genetic makeup scientists are
still at a loss to explain the rather significant differences between
humans and chimps. These differences include physical characteristics
such as our large brain and bipedalism, but more importantly the
ability to think abstractly in terms of concepts, the use of symbols,
highly developed language, free will and self-consciousness. It is
self-consciousness which gives rise to questions ranging from "Who am
I?" and "Where did I come from?" to "Is there a God" and "Is there
life after death?"
Additionally, while suggesting that man descended from apes, Charles
Darwin himself was at a loss to explain the origin of the "moral
sense" that truly distinguishes man from other animals. Of course,
scientists will continue to try to account for these differences in
purely materialistic terms. For instance, they will try to explain
them as arising from the remaining 4 percent of genetic material, or
come up with the "God gene" or the "God center" of the brain.
And according to Prof. Uta Frith from University College (London), our varied mental and social lives make us humans fundamentally different from other species. In particular, our self-consciousness is different from the self-awareness exhibited by great apes - it occurred only in human evolution about 100,000 years ago.