The Foundation of the Origin of Species

Introduction; Essay of 1842; Part I: 1. On variation under domestication, and on the principles of selection; 2. On variation in a state of nature and on the natural means of selection; 3. On variations in instincts and other mental attributes; Part II: 4. On the evidence from geology; 5. On the evidence from geology; 6. Geographical distribution; 7. Affinities and classification; 8. Unity of type in the great classes; 9. Abortive organs; Essay of 1844; Part I: 1. On the variation of of organic beings under domestication, and on the principles of selection; 2. On the variation of organic beings in a wild state, on the natural means of selection, and on the comparison of domestic races and true species; 3. On the variation of instincts and other mental attributes under domestication and in a state of nature, on the difficulties in this subject, and on analogous difficulties with respect to corporeal structures; Part II. On the Evidence Favourable and Opposed to the View that Species are Naturally Formed Races, Descended from Common Stocks: 4. On the number of intermediate forms required on the theory of common descent, and on their absence in a fossil state; 5. Gradual appearance and disappearance of species; 6. On the geographical distribution of organic beings in past and present time; 7. On the nature of the affinities and classification of organic beings; 8. Unity of type in the great classes, and morphological structure; 9. Abortive or rudimentary organs; 10. Recapitulation and conclusion; Index.