Quote from The Descent of Man and Selection in Relation To Sex by Charles Darwin (1871)
The quote below is from a chapter in Evolution, Literature, Film: A Reader (2010).
`…the intellect must have been all-important to [humankind] even at a very remote period, as enabling him to invent and use language, to make weapons, tools, traps, etc., whereby with the aid of his social habits he long ago became the most dominant of all living creatures… the continued use of language will have reacted on the brain and produced an inherited effect; and this again will have reacted on the improvement of language…
The development of the moral qualities is a more interesting problem. The foundation lies in the social instincts, including under this term the family ties. These instincts are highly complex, and in the case of the lower animals give special tendencies towards certain definite actions; but the more important elements are love, and the distinct emotion of sympathy.
Animals endowed with the social instincts take pleasure in one another’s company, warn one another of danger, defend and aid one another in many ways.
These instincts do not extend to all the individuals of the species, but only to those of the same community. As they are highly beneficial to the species, they have in all probability been acquired through natural selection.’
If you want more on that `evolution of morals’ stuff, see Hierarchy In The Forest:
This is why most of the top 20 RoI films are about some villain (some bully, who is trying for social dominance) and people (protagonists) trying to take them down.

Thoughts and Comments, always most welcome.
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JT Velikovsky
Film Story Analyst/Researcher and High RoI Film/Story/Screenplay Guru
The above is an adapted excerpt from my doctoral thesis: “Understanding And Exploring The Relationship Between: Creativity; Theories Of Narratology; Screenwriting; And Narrative Fiction Feature Film-Making Practices.” It is presented here for the benefit of fellow screenwriting and filmmaking researchers.
JT Velikovsky is a produced feature film screenwriter and million-selling transmedia writer-director-producer. He has been a professional story analyst for major film studios, film funding organizations, and the national writer’s guild. For more see:
REFERENCES
Boyd, B, Carroll, J & Gottschall, J (2010) Evolution, Literature, and Film: a Reader, Columbia University Press, New York.