Humans

I've always been fascinated by the idea that human beings became the dominant species.

Based on Darwinian theory, we shouldn't be.

We are not the strongest or the fastest. We have no natural protection from the elements.
In any climate, we require some sort of covering for our hairless bodies. We are not naturally camouflaged. Our faces and skin shines in the night. Our eyesight and hearing are not superior to most other animals.
We cannot swim without a lot of effort. Nature has given us no special advantage in the water.