The Origin of Species: A Variorum Text

CONTENTS

1 CONTENTS [v] 2 INTRODUCTION 2:C ADDITIONS AND CORRECTIONS, TO THE SECOND AND THIRD EDITIONS .. HISTORICAL SKETCH INTRODUCTION .. ztd ADDITIONS AND CORRECTIONS, TO THE FOURTH EDITION HISTORICAL SKETCH INTRODUCTION .. z:e ADDITIONS AND CORRECTIONS, TO THE FIFTH EDITION HISTORICAL SKETCH INTRODUCTION .. 2:/ ADDITIONS AND CORRECTIONS, TO THE SIXTH EDITION HISTORICAL SKETCH INTRODUCTION .. Page 1 Page xi-xii xiii-xix 1-6 Page xi-xii xiii-xxi 1-6 Page xi-xiii xv-xxiii 1-6 Page xi-xii xiii-xxi 1-4 3 4 CHAPTER I. VARIATION UNDER DOMESTICATION. 5 Causes of Variability-Effects of Habit-Correlation of GrowthInheritance -Character of Domestic Varieties-Difficulty of distinguishing between Varieties and Species-Origin of Domestic Varieties from one or more Species-Domestic Pigeons, their Differences and Origin-Principle of Selection anciently followed , its Effects-Methodical and Unconscious Selection-Unknown Origin of our Domestic Productions-Circumstances favourable to Man's power of Selection 7-43 5:C Selection .. 7-44 5:d Differences and Origin-Principles of Selection anciently followed , their Effects/Selection 7-45 5:e Habit-Correlated Variation-Inheritance/Selection 7-47 5:/ Habit and the use or disuse of Parts-Correlated/Selection, anciently/Selection 5-32 43 CHAPTER II. 7 VARIATION UNDER NATURE. S Variability-Individual differences-Doubtful Species-Wide ranging , much diffused, and common species vary most-Species of the larger genera in any country vary more than the species of the smaller genera-Many of the species of the larger genera resemble varieties in being very closely, but unequally, related to each other, and in having restricted ranges .. .. 44-59 8:c ranges 45-62 8:d in each country/ranges 46-69 8:e more frequently than/ranges 48-7° 8:/ species, vary most/ranges 33-47 9 10 CHAPTER III. STRUGGLE FOR EXISTENCE. Page 63-82 Page 70-89 Page 71-9° 48-61 II Bears on natural selection-The term used in a wide sense-Geometrical powers of increase-Rapid increase of naturalised animals and plants-Nature of the checks to increase-Competition universal-Effects of climate-Protection from the number of individuals-Complex relations of all animals and plants throughout nature-Struggle for life most severe between individuals and varieties of the same species; often severe between species of the same genus-The relation of organism to organism the most important of all relations Page 60-79 II:b Its bearing on I I:C Geometrical ratio of increase/relations I i id relations I t :e relations I t t] relations 12 CHAPTER IV. NATURAL SELECTION. I3:e NATURAL SELECTION, OR THE SURVIVAL OF THE FITTEST. I3:/ SELECTION; OR 14 Natural Selection-its power compared with man's selection-its power on characters of trifling importance-its power at all ages and on both sexes-Sexual Selection-On the generality of intercrosses between individuals of the same species-Circumstances favourable and unfavourable to Natural Selection, namely, intercrossing, isolation, number of individuals-Slow action-Extinction caused by Natural Selection-Divergence of Character, related to the diversity of inhabitants of any small area, and to naturalisation-Action of Natural Selection, L14 through Divergence of Character and Extinction, on the descendants from a common parent-Explains the Grouping of all organic beings . . . . . . . . . . . . . . .. 80-13° I4: c beings-Advance in organisation-Low forms preserved-Objections considered-Indefinite multiplication of species-Summary 83-147 14:d Summary 9°-156 /4:e unfavourable to the results of Natural Selection, namely /considered -Uniformity of certain characters due to their unimportance , and to their not having been acted on by Natural Selection-Indefinite/Summary 91-164 I4:1 grouping/preserved-Convergence of character-Indefinite/ Summary Page 62-105 CHAPTER V. LAWS OF VARIA TION. 17 Effects of external conditions-Use and disuse, combined with natural selection; organs of flight and of vision-Acclimatisation -Correlation of growth-Compensation and economy of growth -False correlations-Multiple, rudimentary, and lowly organised structures variable-Parts developed in an unusual manner are highly variable: specific characters more variable than generic : secondary sexual characters variable-Species of the same genus vary in an analogous manner-Reversions to long-lost characters-Summary 131- 17° I7:c Summary 148-188 I7: d Summary .. 157-198 I7:e Effects of changed conditions/Natural Selectiorr/Acclimatisation -Correla ted variation-Com pensation /Summary Page 165-206 I7:1 Summary 106-132 18 CHAPTER VI. DIFFICULTIES ON THEORY. I9:e DIFFICULTIES OF THE THEORY. 20 Difficulties on the theory of descent with modification- Transitions -Absence or rarity of transitional varieties-Transitions in...