* In 1859, an English gentleman naturalist named Charles Robert Darwin published ON THE ORIGIN OF SPECIES, which would prove to be one of the most influential books of the 19th century and one of the most important scientific documents of all time.
THE ORIGIN OF SPECIES, as it is usually referred to, was a carefully researched work, providing a detailed argument to show that the organisms of the Earth had evolved in form over time. Organisms had undergone changes in form from generation to generation due to what would later be known as "mutations", with the "struggle for existence" ensuring that those organisms with beneficial changes would survive and reproduce, while those with harmful changes dying out. Over the aeons, this process of "evolution by natural selection" slowly generated all the different organisms of the Earth from ancestors common to all.
In the 21st century, we know far more about the evolution of life than Darwin did -- but the added knowledge has, by and large, demonstrated just how insightful THE ORIGIN OF SPECIES really was. Unfortunately, casual readers who would like to trace modern evolutionary theory (MET) back to its roots can find THE ORIGIN OF SPECIES a difficult and opaque read, full of ideas that can be difficult to pick out. Its writing style and methods of reasoning are distinctly Victorian, and obviously there were many important things that Darwin didn't understand; in many cases, he admitted as much.
This document hopes to make life easier for the casual reader interested in Darwin by providing a short outline of THE ORIGIN OF SPECIES, built on a framework of citations from the book, fleshed out with summaries and commentaries to reflect the benefit of hindsight. I should emphasize that this document is not an introduction to modern evolutionary science as such, though it does serve as one to an extent. Readers after a simple introduction to that subject may be interested in the companion document:
This outline is based on the first edition of THE ORIGIN OF SPECIES. It does make occasional references to the sixth and final edition, published in 1872. References to materials appearing in the final edition but not the first edition are specifically noted; some of these materials may have originally appeared in the second through fifth editions, but for the sake of simplicity, that distinction is not considered here.