- 01Title page and epigraph
On the Origin of Species
Natural selection and evolutionary theory.
24Chapters
128Lessons
343Topics
Certificate of completion included
This course was produced by Cavua from a public-domain text.
Skills this course leaves you with.
- Explain the core principles of natural selection and evolutionary theory
- Describe variation under domestication and variation under nature
- Analyze the struggle for existence and its role in species change
- Summarize how natural selection leads to adaptation, divergence, and extinction
- Interpret Darwin's arguments about inheritance, hybridism, and the geological record
- Connect geographical distribution and fossil evidence to evolutionary change
Curriculum
The full table of contents.
Every chapter, every lesson, every topic — laid out before you enroll. Click any chapter to expand it.
- Chapters
- 24
- Lessons
- 128
- Topics
- 343
- 01Introduction
- 02Variation under domestication
- 01Inheritance and domestic variation
- 02Variation under nature
- 03Struggle for existence
- 04Natural selection and sexual selection
- 01Laws of Variation
- 02Difficulties on Theory
- 01The law of unity of type and conditions of existence
- 02Instinct
- 03Hybridism
- 04Imperfection of the geological record
- 01Geological succession of organic beings
- 02Geographical distribution
- 03Geographical distribution continued
- 04Mutual affinities, morphology, embryology, and rudimentary organs
- 01Recapitulation of natural selection and species change
- 01Origin of Species
- 01Darwin’s motivation and publication context
- 02Limits of the abstract and acknowledgments
- 03Why species are modified
- 04Planned structure of the book
- 05Concluding statement of descent and natural selection
- 01Greater variability under domestication
- 02Reproductive system and confinement
- 03Sports and bud variation
- 04Direct effects of conditions of life
- 01Direct action of conditions and habit
- 02Correlation of growth and inherited variation
- 03Inheritance, reversion, and age of appearance
- 01Reversion under unchanged conditions
- 02Domestic races compared with species
- 03Uncertain ancestry of domestic breeds
- 01Multiple origins of domestic animals
- 02Uncertain ancestry of ancient domesticated species
- 03Probable wild ancestors of dogs, cattle, poultry, ducks, and rabbits
- 01Domestic breeds and crossing limits
- 02Domestic pigeons and breed diversity
- 01Distinctive breeds and inherited variation
- 02Arguments for descent from the rock-pigeon
- 03Evidence for the origin of domestic pigeons
- 04Breeders’ belief in distinct species
- 01Accumulative selection in domestic races
- 02Breeders, horticulturists, and correlated variation
- 01Unconscious selection in breeding
- 01Origin of our Domestic Races
- 01Circumstances favourable to man’s power of selection
- 01Selection, breeding, and the formation of domestic races
- 01Variability and individual differences
- 02Polymorphic genera and doubtful species
- 01Varieties as incipient species
- 02Species, varieties, and individual differences
- 03Species that vary most
- 01Dominant species and wide-ranging varieties
- 02Larger genera and the prevalence of varieties
- 01Analogies between large genera and varieties
- 02Restricted ranges of closely allied species
- 03Consequences for the diversification of life
- 01Preliminary remarks on struggle for existence and natural selection
- 01Universal struggle for life
- 02Metaphorical meanings of struggle for existence
- 03Geometrical increase and inevitable destruction
- 04Evidence from rapid population growth
- 01Checks on population increase
- 02Food, predation, and climate as limiting factors
- 01Checks from epidemics, parasites, and crowding
- 02Interdependence of heath, firs, cattle, and insects
- 03Pollination links among bees, mice, and plants
- 01Checks acting on species numbers
- 02Competition among species and varieties
- 01Competition between allied species
- 02Organic structure and competition
- 03Seed nourishment and seedling survival
- 04Limits to population increase
- 01Competition in new countries
- 01Natural selection as preservation of favourable variations
- 02Natural selection compared with man’s selection
- 03Selection on trifling characters and correlated growth
- 01Sexual selection and male rivalry
- 02Female choice and ornamental traits in birds
- 01Wolf prey and inherited hunting habits
- 02Nectar, insect visits, and cross-fertilisation
- 03Separation of the sexes in plants
- 01Mutual adaptation of bees and flowers
- 02Natural selection as gradual accumulation
- 03Occasional cross-fertilisation in hermaphrodites
- 04Evidence from flowers, hybrids, and trees
- 01Occasional intercrossing in animals and plants
- 02Conditions that favor natural selection
- 03Isolation and large areas in species formation
- 04Large continental areas and island isolation
- 05Fresh-water basins and living fossils
- 06Summary of favourable circumstances for natural selection
- 01Extinction and the struggle for life
- 01Extinction of less competitive forms
- 02Principle of divergence in domestic breeding
- 03Diversification and the struggle for places in nature
- 04Divergent variation from a common species
- 05Extinction of intermediate and parent forms
- 06Formation of new genera and sub-genera
- 07Extinct beings and branching descent
- 08From genera to families and orders
- 09Future dominance of larger groups
- 01Natural selection and sexual selection
- 02Extinction, divergence, and affinities of organic beings
- 01Classification as a branching tree of life
- 01Effects of external conditions on variation
- 01Direct and indirect effects of climate and conditions of life
- 02Effects of use and disuse in domestic and wild animals
- 03Blindness and eye reduction in cave animals
- 01Habit and acclimatisation in plants and animals
- 02Natural selection, habit, and constitutional flexibility
- 01Correlation of growth and homologous variation
- 02Examples of correlated structures in plants and animals
- 03Misleading correlations and compensation of growth
- 01Compensation between organs
- 02Natural selection economising organisation
- 03Variation in repeated parts
- 01Rudimentary parts and variable organs
- 02Extraordinary development and high variability
- 03Domestic selection and fluctuating characters
- 01Specific characters versus generic characters
- 02Secondary sexual characters and sexual selection
- 01Analogous variations in domestic races and plants
- 02Reversion to ancestral characters in pigeons
- 03Inherited tendencies and ancestral reappearance
- 01Reversion and analogous variation in domestic breeds
- 02Striping in horses and horse hybrids
- 01Reappearance of ancient equine and pigeon characters
- 02Summary of the laws of variation
- 01Absence or rarity of transitional varieties
- 01Intermediate varieties and fossil evidence
- 02Transitions to aquatic, gliding, and flying habits
- 03Changed and diversified habits within species
- 01Organs of extreme perfection and complication
- 01Gradations in the eye and natural selection
- 02The eye compared with a telescope
- 01Conversion of organs by natural selection
- 02Neuter insects and electric organs as difficulties
- 01Electric organs as a difficulty for descent
- 02Gradual transitions and the canon of nature
- 03Organs of little apparent importance
- 01Trifling characters and natural selection
- 02Secondary causes and correlated variation
- 03Examples of apparently unimportant adaptations
- 01Structures with no direct use to their possessors
- 02Structures evolved for the good of other species
- 03Limits of perfection under natural selection
- 01Objections to the theory and missing intermediates
- 02Gradual change in habits and organs
- 03Natural selection, competition, and the laws of existence
- 01Instinct compared with habit
- 02Variation and natural selection of instincts
- 03Aphides and ants
- 01Inherited domestic instincts in dogs and other breeds
- 02Habit, selection, and the loss of natural instincts
- 03Examples for instincts in nature: cuckoo, ants, and bees
- 01Cuckoo's parasitic nesting instinct
- 02Ostrich egg-laying and shared nests
- 03Parasitic bees and wasp-like insects
- 01Formica rufescens and dependence on slaves
- 02Observations on Formica sanguinea in England
- 03Slave raids, pupae capture, and species discrimination
- 01Slave-making instinct in Formica sanguinea
- 02Hive-bee comb construction
- 01Gradation from humble-bee to hive-bee cells
- 02Geometric explanation of hive-bee comb construction
- 03Experiments with wax strips and vermilion ridges
- 04Construction of the comb wall
- 05Cooperative cell building by many bees
- 06Rough walls and hexagonal foundations
- 01Economy of wax in hive construction
- 02Natural selection and the perfect hexagonal comb
- 01Sterile females as a difficulty for natural selection
- 02Working ants and correlated differences
- 01Selection acting on the family in social insects
- 02Gradations among ant worker castes
- 01Neuter insects and division of labour
- 02Summary of instinct and natural selection
- 01Sterility of first crosses and hybrids
- 02Effects of close interbreeding on hybrid fertility
- 03Horticultural and animal hybrid experiments
- 01Sterility in first crosses and hybrids
- 02Sterility of first crosses and hybrids
- 03Sterility as an incidental result of reproductive differences
- 01Grafting and hybridisation compared
- 02Causes of sterility in first crosses
- 03Sterility of hybrids under unnatural conditions
- 04Parallel between slight changes and slight crosses
- 01Fertility of varieties under nature and domestication
- 02Cases of partial sterility in varieties
- 01Comparison of hybrids and mongrels
- 02Resemblance to parent forms and reversion
- 01Sterility of first crosses and hybrids
- 02Fertility of varieties and mongrels
- 01Intermediate varieties and the geological record
- 02The lapse of time shown by deposition and denudation
- 01Poorness of palæontological collections
- 01Fragmentary preservation of terrestrial and mammalian remains
- 02Wide time gaps between formations
- 03Why geological formations are intermittent
- 04Subsidence and fossil-rich deposits
- 05Elevation, subsidence, and missing transitional forms
- 01Why intermediate varieties are rarely preserved
- 02Species, varieties, and the difficulty of recognition
- 03Preservation of transitional gradations
- 04Malay Archipelago as an imperfect record
- 01Why transitional forms are rarely preserved
- 02Sudden appearance of allied species in formations
- 03Examples from mammals, monkeys, whales, and cirripedes
- 01Sudden appearance of allied species in the lowest fossiliferous strata
- 01Slow appearance and differing rates of species change
- 02Extinction and the nonreappearance of lost species
- 03Natural selection and uneven geological succession
- 01Gradual appearance and disappearance of groups
- 02Extinction as a gradual process
- 03Competition, rarity, and replacement of species
- 01Extinction and natural selection
- 02Parallel succession of marine life worldwide
- 03Dominant species, diffusion, and extinction
- 04Blank intervals and contemporaneous formations
- 01Parallel succession in separate regions
- 02Extinct species and living forms in one natural system
- 03Intermediate character of ancient genera and faunas
- 04Intermediate character of successive faunas
- 05Closely related fossils in consecutive formations
- 01Development of ancient forms and natural selection
- 01Succession of the same types within the same areas
- 01Extinction and modified descendants
- 02Summary of the geological record and succession
- 01Objections from the fossil record
- 02Descent with modification explains paleontology
- 01Geological succession and inheritance
- 01Physical conditions and species distribution
- 02Barriers and migration
- 01Barriers separating continents and seas
- 02Inheritance with modification across regions
- 01Single birthplace and migration of species
- 02Related species in neighboring regions
- 03Individuals descended from one pair or many
- 01Means of dispersal
- 01Occasional means of distribution
- 02Seed flotation and seawater experiments
- 01Sea currents and floating driftwood
- 02Birds, fish, and icebergs as seed carriers
- 03Limits of accidental transport
- 01Glacial-period dispersal of alpine and arctic species
- 02Earlier warm-period continuity of circumpolar land
- 03Southern migration and modification of temperate species
- 04Marine faunas of disjoined seas
- 05Limits of the creation theory
- 01Former glacial action across the world
- 02Glacial period and species distribution
- 01Temperate plants invading the tropics during glaciation
- 02Return migration and mountain refuges after warming
- 01North-to-south migration of plants
- 02Remaining difficulties in species distribution
- 01Former antarctic flora and glacial dispersal
- 02Great climatic cycles and geographical distribution
- 01Dispersal of fresh-water fish and shells
- 02Dispersal of fresh-water plants by birds
- 03General principles of fresh-water distribution
- 01Scarcity of species on oceanic islands
- 02High proportion of endemic island species
- 03Immigration, hooked seeds, and island trees
- 04Absence of frogs and terrestrial mammals
- 05Bats and deep-sea barriers in the Malay Archipelago
- 06Depth of sea and mammalian affinity
- 07General evidence for occasional transport
- 08Land-shell dispersal across oceans
- 01Affinity of island species to nearby mainlands
- 02Galapagos and Cape Verde comparison
- 03Other island biogeography exceptions
- 01Galapagos island species and natural selection
- 01Pre-occupation and island species separation
- 02Oceanic islands and related colonists
- 01Migration, allied species, and doubtful forms
- 02Wide-ranging genera and species ranges
- 03Ancient genera and slow-changing lower forms
- 01Summary of geographical distribution and migration
- 01Classification and groups subordinate to groups
- 01Natural system and descent
- 02Classificatory value of organs and rudimentary structures
- 01Importance of trifling characters in classification
- 01Chains of affinities in classification
- 02Genealogical arrangement and degrees of modification
- 03Languages as a model of descent
- 01Classification of varieties by descent and constant characters
- 02Descent as the basis of species and higher groups
- 03Real affinities versus analogical resemblances
- 04Numerical parallelism and the dominance of large groups
- 05Aberrant groups and extinct intermediates
- 06General affinities between distinct orders
- 07Radiating affinities within families
- 08Extinction and natural classification
- 01Homologous organs and unity of type
- 02Natural selection and modified organ patterns
- 03Homology within the same individual
- 01Serial homologies and repeated parts
- 02Metamorphosed organs and common elements
- 03Embryonic resemblance across species
- 01Embryonic resemblance and larval adaptation
- 02Variation appearing at corresponding ages
- 03Late-appearing variations and inherited age
- 04Embryonic resemblance in descendants
- 05Embryos as evidence of descent
- 01Rudimentary, atrophied, or aborted organs
- 01Rudimentary organs and inheritance
- 02Summary of classification, morphology, embryology, and descent
- 01Objections to natural selection
- 02Geological record and fossil gaps
- 03Evidence from domestication and variability
- 01Selection under domestication and nature
- 02Species, varieties, and divergence
- 01Natural selection and the grouping of life
- 02Adaptation, imperfection, and variation
- 03Instincts and inherited characters
- 01Geological record and extinction
- 02Geographical distribution and migration
- 03Classification, homology, and embryology
- 04Rudimentary organs and concluding recapitulation
- 01Difficulty of admitting species change
- 02Limits of current naturalists' objections
- 01Extent of descent with modification
- 02Common ancestry of all organic beings
- 03Effects on systematics and species
- 01Natural history as a historical science
- 02Variation, classification, and migration
- 03Geology and the imperfection of the fossil record
- 01Organic change as a measure of time
- 02Future of psychology and human history
- 03Descent from common ancestors and future progress
- 01Natural laws shaping life’s diversity
- 01A–B index entries
- 02C–D index entries
- 03E–G index entries
- 04H–K index entries
- 05Index entries from Lamarck to Lyell
- 06Index entries from Madeira to Owen
- 07Index entries from Paley to Richardson
- 08Index entries from Ramsay to Thwaites
- 09Index entries from Tierra del Fuego to Youatt
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