The Engineering Problem in Evolutionary Biology

I was amazed just a few years ago I wrote a book of apologetics, and I was looking into some of this. Some of the stuff that I took as gospel truth is no longer accepted. To build an animal, it turns out you not only need all this genetic information, but there are circuits. And these circuits are crucial to getting the right cells to differentiate from each other. But they can't alter the original circuit without destroying the animal during its development.