The family is the social base, all starts from there, with the unity as main need, since clearly a group of people that focus towards the same goal, tends to success in a more effective way compared to be without the support of other ones.
The cultures that placed considerable importance on the good functioning, organization, and contributions of a family, were most likely to succeed and endure in the time.
Each member of the family had a different task to do depending on their skills, so the grown men had the advantage for duties related to hunt and fishing, young men and women harvesting fruits or cooking.
This unity and organization allowed the different families and clans to be more successful due to the mutualism and help that all the members could bring to each other, thanks to this the human and people congregations managed to survive the harsh conditions of different eras of the earth and evolve to the modern society we live on.