Despite widely published reports that Angelina Jolie was originally cast as the lead, but dropped out, Luc Besson has since denied them and admitted that he only met with a couple of actresses to discuss playing the lead role. He says when he saw how strongly Scarlett Johansson reacted to the story, she immediately landed the part.
In an interview on 08/03/2014 (evening news on France 2), Luc Besson said that this project took 10 years to become a reality. Also, he admitted that he knew that some scientific assumptions were erroneous, e.g. that humans use only 10% of their brain. Nonetheless, he said that "[such assumption] would be a great start for a sci-fi movie".
The human-looking ape seen in some scenes is Australopithecus afarensis, who represents the 'missing link' between apes and humans, nicknamed 'Lucy' after John Lennon's song "Lucy in the Sky with Diamonds." She lived 3.2 million years ago and is the earliest known hominid to walk upright like humans.
In 1974, Donaled C. Johanson discovered a 3.2 million year old skeleton in Ethiopia. He called it Austalopithecus Afarensis, later nicknamed "Lucy" In the movie, the lead character Lucy is played by Scarlett Johanson.