Nature and Survival

Just observe nature around you:
everything seems at first glance idyllic and beautiful.
But a more deep observation will reveal the true:
everything is fighting for survival!
Life can be described simply as to stay alive or to die.
There are many strategy to survival.
For animals, one often chosen way is to build groups.
A group protect individuals and sometime they sacrificed one of their for the sake of the others. Think about the big heard of gazelles, gnus, zebras in Africa which stay together in order to survive to predators attacks. And on the other side of the line the predators which hunt in group in order to succeed and catch food.
The same happened to mankind struggling for survival and finding the building of groups (family, tribe) as the best strategy to approach this goal.