Great site, Sandman, thanks.
I believe, but cannot prove, that life on Earth comes from spontaneous evolution, i.e., life, including human, evolved relatively simultaneously from the primordial soup all over the globe.
This accounts for the basic competitiveness of all life forms for their own space and survival. DNA aside, there is no single thread of humanity let alone all life. There were many Eves, and their heirs continue to compete.
If cooperation proves the most successful way to thrive, it is done.
If competition proves the most successful way to thrive, it is done.
If exterminating rivals proves the most successful way to thrive, it is done.
Cooperation and sharing is best achieved from a position of strength. It is rarely achieved from a position of weakness.
Relative peace is achieved only in proportion to the number of people perceiving not only that they have equitable shares of the communal wealth, but are respected for their contributions to it.
Thus spake Halothustra.