He called these varieties 'incipient species'. Darwin has to demonstrate that individual differences can gradually accumulate to the point of creating new varieties which diverge away from the parent species. The constant small variations or differences between individuals were, in effect, the raw material available for natural selection. This chapter is one long statement of the extreme variability of sexually reproducing species. The third part of the chapter explores how selection by man actually works. The second is a ten-page essay on the domestic pigeon, seeking to show the incredible variety of forms which breeders have produced from a single wild species by selecting from slight variations in individuals. The first deals with issues around fertility and sterility, to show that domesticated varieties can generally produce fertile offspring with one another which reveals their common ancestry. The chapter can be thought of as having three parts. This chapter seems designed to show that all the animals and plants that man has bred have been produced by artificial selection. Finally he declares his conviction that natural selection 'has been the main but not exclusive means of modification'. This sort of interrelation could not be brought about by species just somehow 'progressing'.ĭarwin's last paragraph makes plain that he has barely scratched the surface of understanding how nature works, but states boldly that 'after the most deliberate study and dispassionate judgement' of which he is capable, he is certain that evolution is a fact. But such a naturalist would remain unsatisfied without a mechanism to explain all the 'co-adaptations' in nature, such as the intricate ways in which the mistletoe relies on various trees, birds and insects for its existence. A naturalist might become convinced that new species had descended from other species. He then moves on to a short summary of his book. It is essential, however, to read the whole book to understand its arguments and evidence and therefore its impact.ĭarwin's introduction gives a brief account of how he became convinced of evolution following the voyage of the Beagle, and how he had gradually developed his theory. The following is a summary of the Origin taking each chapter in turn. (The boundary between the two parts of the book is not always as clear as implied here, as chapter nine is closely related to ten.) Chapter fourteen is a recapitulation and conclusion. These last four chapters deal with geology, geography, taxonomy, morphology and embryology. These chapters lay down what requires the explanation provided in the first four chapters. The second part of the Origin,chapters ten to thirteen, attempts to cover what exactly natural selection is competent to explain about the history and diversity of life. Chapters five to nine deal with a range of issues and difficulties which impinge on this competence. Of these chapters the first three establish its existence and the fourth makes the case for its ability to explain common ancestry. The first part, chapters one to nine, establishes natural selection as a true cause. The book is called Origin of species because it answered the question, what is the origin or source of new species? Where did they come from? He argued that they were not specially created from nothing but descended from earlier species. His second argument was that the process he called 'natural selection' was responsible for how species change and become adapted. In other words, he wanted to convince his readers that evolution is a fact. His first was that the different species of living things on Earth evolved by natural means from earlier ancestors. In it, he offered two separate but intertwined arguments. Darwin's Origin of species, first edition (1859) An introduction by Gordon Chancellor and John van WyheĬharles Darwin's Origin of species of 1859 is one of the most important books ever published.