Simplify the following text for a Grade 7 native English-speaking person.
Original: Darwin 's book did not address the question of human evolution , saying only that `` Light will be thrown on the origin of man and his history '' .
Simplified: In this book , Darwin wrote about the idea of evolution in general , rather than the evolution of humans . Light will be thrown on the origin of man and his history , was all Darwin wrote on the subject .