Share your ideas and questions about the Example Signatures video.

I was playing around a bit with the Game of Life to try to find some signatures of such 2D CAs and noticed that it seemed strange to say that such a signature would exist - theoretically, any imaginable 0-th generation layout could be considered a signature, even if it was self-destructing. It seems to make more sense to look at emergent patterns, but that seems to presuppose that you can have an equivalent of evolution in a 2D CA. Am I considering this wrong or could it be that signatures only really make sense in full-blown planetary enviroments?