Nationalism and humanity

I had a thought the other day. I'm reading through a fantastic book by Stephen Baxter called Voyage. I'm also listening to Carl Sagan's Pale Blue Dot on audiobook.

Put these two together, I thought about the concept of first settlers to Mars. Let's suppose their nationality is USA, or at least NASA has collaborated with perhaps ESA and have their big letters stencilled on the booster. Man (or woman) sets foot on the red earth dust and claims the planet for all people of the USA. Of course not! Besides all the deals that have been done about space exploration, and no country being able to claim any space for their own benefit, it would cause a massive uproar.

Wind the clock back 200 years, English white man set foot on Australian shores to claim Terra Australis for the mother kingdom. Local aborigines obviously detested the concept and still do today. The same goes for aboriginal cultures around the world.

Wind the clock back anothe 40,000 years, Java man walks/canoes to Arnham Land and sets foot on Australia for the first time, slowly settling their tribes where they can.

This would have happened before this in lands closer to Africa/middle east. When Neanderthal and Homo Sapien lived in the same time (apologies if I have my species incorrect), there would have been warring tribes (if they could be categorised as such),  potentially mating amongst the two groups. Eventually our ancestors won over, so to speak.

So why should the timing of the appearance of a particular species of man into a certain area mean they should claim ownership of the land.

If I may be so bold and put this into contemporary context - why should Australian aborigines have any more claim over the great southern land than Anglo-white man?

We are both of the same species, race really is skin deep and should not be considered. Sure, the way anglos conquered this land was poor form, but that is the past and we have to deal with our situation today. While preserving cultures of both, can we not appreciate we are of the same species and land cannot be owned by anyone?

I know I'm not articulating this any where near as clearly as I was thinking about it, and I'm sure many people have considered these arguments in the past. But I had to get these thoughts out.