Most of the people can’t imagine the world as a whole family, but we actually are. We share common ancestors and genetically we are almost completely identical - the human genome is mostly the same in all people.
We seem quite different, but these differences are not significant from a biological point of view, so we are all sisters and brothers. The colour of our skin, hair and eyes, the differences in the height and weigh they are result only of small genetic variations. Yet these small differences are enough to create people with different appearances and different health.
But the biology is not the only way that shows our similarity. If you ask any person from any place in the Earth: "What do you want from life?" The answer will be the same: being in a good health, have a food, have a job, have a loving family and friends. If it wasn’t like that how do you think the social networks would be so popular?!
But if we are one family, why do we want constantly to harm each other?
I think it is mainly, because of the lack of education. If the people have a possibility to learn how the nature works, what is genetics, what is physics, who is Einstein.... they would be more concern about the world as an entity.
Better education leads to less violence against the others and against the nature, and would make the people understand that we are all one big family!
http://www.nigms.nih.gov/Education/Factsheet_GeneticVariation.htm
http://humanorigins.si.edu/evidence/genetics/one-species-living-worldwide
