The Origin of Species is a book written by Charles Darwin.
After creationism became the only theory of life taught at Springfield Elementary, Lisa hold the secret meeting for nerds to keep Darwin's theory alive in Springfield. She was reading his book to nerds, but was then arrested for teaching evolution. Lisa was put on trial and Marge decided to read the too. After reading, she found out that Darwin's arguments are very persuasive and found the way how to help Lisa to win the trial.