This thread is made of human-centric Taker worldview, and it makes me sad. A brief history of time as told by a jellyfish:
Big Bang-Formation of Solar System- Formation of Earth- Life arises- After millions of years of struggle and evolution, finally, Jellyfish appeared. (paraphrased from Ishmael, by Daniel Quinn)
Humans are neither the 'end product' of evolution, or even finished developing. Intelligence (sentience?) isn't an unavoidable outcome.
This guy had it right:
That's not really how evolution works. It'll be more like this: http://en.wikipedia.org/wiki/Ascension_(Stargate)
Depending on how define intelligence or sentience (most undefined and overused term ever) all organisms can be said to have both.
Going by the most common folk definition of intelligence as human-like ability to solve problems and what I take the op meant to be self-awareness, instead of sentience, a lot of other animal species already have those. The chimp and the other great apes being the most obvious ones.