Their were two kinds of humans, homosapiens and neantherthals. The neantherthals were more efficient than the homosapiens. But the neantherthals lacked intelligence meanwhile the homosapiens did not. The neantherthals was a brutal species. The homosapiens were a peaceful human species. They only fought when it was needed. When the neantherthal popoulation began to dissapear, a homosapien and a neantherthal crossed eachothers paths. The neantherthal challenged the homosapiean to a duel of death. The homosapien won, basically the exsisting humans today are homosapiens.
What if their was another kind of human species. A human species that could fly. Similar to a bird this kind will only have hollow bones. They would have no wings. If they wanted to fly they would use constant energy and stamina. If they wanted to go faster they would use a little more energy and bit more stamina. What they would do is that they would go down into the surface to catch speed and go back up to remain flight. But their is a minus to all their abillities. Their bones are hollow so that means that their bones must be weak. The slightest strike could break their bones. We all know that the homosapien will win in this fight. The real question is that would have want to stay as yourself right now or be able to fly? In my opinion I would want o stay in my regular state because would have wanted to have been weak and spineless. Sure you have the ability to fly but their will be a bigger chance of you dying. So I believe that homosapiens are the dominate species.