Somebody gets it
I was explaining why these evolutionary precursors of humanity were a different species, and even genus from modern humans. We looked at slides of the fossil remains of homonids along with chronometric dating information. We discussed differences in cranial capacity, jaw size, dentition, and placement of the foramen magnum (the hole at the base of your skull). At one point, one of the kids made a comment about humans having sex with australopithicenes. I had to explain that just as humans were not around during the era of dinosars (and therefore couldn't have had sex with them), there were also no modern humans around during the time of A. afarensis or other Australopithicenes.
Another one of the kids piped up and said, " What about Moses and them? Weren't they around back then?" I then had to explain that Moses, if he lived, did so roughly 5,000 years ago, while the hominids under discussion were 2-5 million years old.
You could actually see the light bulb go on in this kid's head. "Man so the Bible ain't right about that. I knew it!" If I was a more gifted teacher, I might have steered the discusion toward the difference between spiritual and scientific truth, but I was just thrilled to have had a kid in this class appear to learn something. After a few minutes of discussion, I moved along with my lesson plan.
The point is not, I don't think, to introduce oppositional discourse into classrooms, but to present scientific evidence that allows kids to draw their own conclusions. Asking the right questions and presenting up-to-date science, that engages interest and promotes critical thinking is the way to go about this.