Origin of Species by Charles Darwin

Table of Contents

• Introduction
• Chapter I. Variation Under Domestication
  • Causes of Variability
  • Effects of Habit and the use or disuse of Parts; Correlated Variation; Inheritance
  • Character of Domestic Varieties; Difficulty of distinguishing between Varieties and Species; Origin of Domestic Varieties from one or more Species
  • Breeds of the Domestic Pigeon, Their Differences and Origin
  • Principles of Selection, anciently followed, their Effects
  • Unconscious Selection
  • Circumstances favourable to Man's power of Selection
• Chapter II. Variation Under Nature
  • Variability
  • Individual Differences
  • Doubtful species
  • Wide ranging, much diffused, and common species, vary most
  • Species of the larger genera in each country vary more frequently 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.
  • Summary
• Chapter III. Struggle for Existence
  • Its bearing on natural selection
  • The term, Struggle for Existence, used in a large sense
  • Geometrical ratio of increase
  • Nature of the checks to increase
  • Complex relations of all animals and plants to each other in the struggle for existence
  • Struggle for life most severe between individuals and varieties of the same species
• Chapter IV. Natural Selection; or the Survival of the Fittest
  • Natural Selection
  • Sexual Selection
  • Illustrations of the action of Natural Selection, or the survival of the fittest
  • On the Intercrossing of Individuals
  • Circumstances favourable for the production of new forms through Natural Selection
  • Extinction caused by Natural Selection
  • Divergence of Character
  • The Probable Effects of the Action of Natural Selection through Divergence of Character and Extinction, on the Descendants of a Common Ancestor
  • On the degree to which Organisation tends to advance
  • Convergence of character
  • Summary
• Chapter V. Laws of Variation
  • Effects of changed conditions
  • Effects of the increased use and disuse of parts, as controlled by Natural Selection
  • Acclimatisation
  • Correlated variation
  • Compensation and economy of growth
  • Multiple, rudimentary, and lowly organised structures are variable
  • A part developed in any species in an extraordinary degree or manner, in comparison with the same part in allied species, tends to be highly variable
  • Specific characters more variable than generic characters
  • Secondary sexual characters variable
  • Distinct species present analogous variations, so that a variety of one species often assumes a character proper to an allied species, or reverts to some of the characters of an early progenitor
  • Summary
• Chapter VI. Difficulties of the Theory
  • Difficulties of the theory of descent with modification
  • Absence or rarity of transitional varieties
  • On the origin and transition of organic beings with peculiar habits and structure
  • Organs of extreme perfection and complication
  • Modes of transition
  • Special difficulties of the theory of Natural Selection
  • Organs of little apparent importance, as affected by Natural Selection
  • Utilitarian doctrine, how far true: Beauty, how acquired
  • Summary
• Chapter VII
  • Miscellaneous Objections to the Theory of Natural Selection
• Chapter VIII. Instinct
  • Instincts comparable with habits, but different in their origin
  • Inherited changes of habit or instinct in domesticated animals
  • Special instincts; Instincts of the cuckoo
  • Slave-making instinct
  • Cell-making instinct of the hive-bee
  • Objections to the theory of natural selection as applied to instincts: neuter and sterile insects
  • Summary
• Chapter IX. Hybridism
  • Distinction between the sterility of first crosses and of hybrids
  • Degrees of sterility
  • Laws governing the sterility of first crosses and of hybrids
  • Origin and causes of the sterility of first crosses and of hybrids
  • Reciprocal dimorphism and trimorphism
  • Fertility of varieties when crossed and of their mongrel offspring not universal
  • Hybrids and mongrels compared independently of their fertility
  • Summary of Chapter
• Chapter X. On the Imperfection of the Geological Record
  • On the absence of intermediate varieties at the present day
  • On the lapse of time, as inferred from the rate of denudation and of deposition
  • On the poorness of our palaeontological collections
  • On the absence of numerous intermediate varieties in any single formation
  • On the sudden appearance of whole groups of allied species
  • On the sudden appearance of groups of allied species in the lowest known fossiliferous strata
• Chapter XI. On the Geological Succession of Organic Beings
  • On the slow and successive appearance of new species
  • On extinction
  • On the forms of life changing almost simultaneously throughout the world
  • On the affinities of extinct species to each other and to living species
  • On the state of development of ancient compared with living forms
  • On the succession of the same types within the same areas, during the later Tertiary Periods.
  • Summary of preceding and present chapter
• Chapter XII. Geographical Distribution
  • Present distribution cannot be accounted for by differences in physical conditions
  • Single centres of supposed creation
  • Means of dispersal
  • Dispersal during the Glacial period
  • Alternate Glacial periods in the north and south
• Chapter XIII. Geographical Distribution -- continued
  • Distribution of fresh-water productions
  • On the inhabitants of oceanic islands
  • Absence of Batrachians and terrestrial Mammals on oceanic islands
  • On the relation of the inhabitants of islands to those of the nearest mainland
  • Summary of the last and present chapter
• Chapter XIV. Mutual Affinities of Organic Beings: Morphology -- Embryology -- Rudimentary Organs
  • Classification
  • Analogical resemblances
  • On the nature of the affinities connecting organic beings
  • Morphology
  • Development and embryology
  • Rudimentary, atrophied, and aborted organs
  • Summary
• Chapter XV
  • Recapitulation and Conclusion
• Glossary of Scientific Terms