Continuum Of Consciousness

Human beings like to think of themselves as being superior to (other) animals. How so? Some will say that we are blessed with consciousness whereas "lower" animals don't. I can't help settle this question: I've never been inside the mind of a cow. But it may be helpful to look at the evolutionary endpoints.

At the primitive endpoint of evolution we find single-cell bacteria; the thought that bacteria have consciousness is rather disturbing so let's assume that they don't. At the other endpoint, the sophisticated one, we find humans, who, in general, are endowed with consciousness. This begs the Darwinian question, at what point in the progression of evolution was consciousness introduced, and how exactly did that happen?

Or perhaps one of our assumptions is wrong?

Zzzzz...

[Homage to the Intermediate Value Theorem]