What makes us uniquely human? Why are we able to dominate the planet? Is it reason? language? art? science?
Uniquely human, unique from animals? Not much, really. How'd we dominate the planet? Agriculture, everything else has been how to deal with the resultant population boom.
I think our language skills combined with having opposable thumbs and the ability to stand on two legs is what makes us unique. With these traits we are able to pass on information, manipulate tools and hunt very effeciently which eventually lead us to argiculture and the domestication of suitable animals.
It's a good question. There are lots of answers. Aside from our DNA, I think what makes us uniquely human is our self aware nature. We have a concept of our selves from a position of the Other. We have the ability to rise above our basic, animal instincts, and perceive things in the abstract.
It's essentially the Arts & Sciences that makes us Human. This is a broad description, of course, and it's debatable which aspects of the Arts & Sciences are the most important in making us what we are-- and how a different emphasis would have changed the way civilization developed. The physical capacity for complex language and the ability to create and use tools with our opposable thumbs is also vital in building a civilization-- it's very likely the ability to put our thoughts to use in the real world created a feedback loop that encouraged the evolution of our brains. But other species have these abilities, too, as well as traits that could be considered rudimentary versions of the Arts & Sciences, however Humanity has a perfect storm of mental and physical abilities that brought us from being just another transient component of the ecology and turned us into philosophers and scientists (although some of us are certainly dragging their feet in that regard).
Emotion. I think that's really what it boils down to. You may be physically or mentally incapacitated, but you are still human because you still feel.