TABLE OF CONTENTS
- Introduction
Chapter I Variation under
Domestication
- Causes of Variability
- Effects of Habit
- Correlation of Growth
- Inheritance
- 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.
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 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.
Chapter III Struggle
for Existence
- 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.
Chapter IV Natural
Selection
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, through Divergence of Character and Extinction,
on the descendants from a common parent
- Explains the Grouping of all organic beings.
Chapter V Laws
of Variation
- 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.
Chapter VI Difficulties
on Theory
- Difficulties on the theory of descent with
modification
- Transitions
- Absence or rarity of transitional varieties
- Transitions in habits of life
- Diversified habits in the same species
- Species with habits widely different from those of their allies
- Organs of extreme perfection
- Means of transition
- Cases of difficulty
- Natura non facit saltum
- Organs of small importance
- Organs not in all cases absolutely perfect
- The law of Unity of Type and of the Conditions of Existence embraced by the
theory of Natural Selection.
Chapter VII Instinct
- Instincts comparable with habits, but
different in their origin
- Instincts graduated
- Aphides and ants
-
Instincts variable
- Domestic instincts, their origin
- Natural instincts of
the cuckoo, ostrich, and parasitic bees
- Slave-making ants
- Hive-bee, its
cell-making instinct
- Difficulties on the theory of the Natural Selection
of instincts
- Neuter or sterile insects
- Summary
Chapter VIII Hybridism
- Distinction between the sterility of first
crosses and of hybrids
- Sterility various in degree, not universal, affected
by close interbreeding, removed by domestication
- Laws governing the
sterility of hybrids
- Sterility not a special endowment, but incidental on
other differences
- Causes of the sterility of first crosses and of hybrids
- Parallelism between the effects of changed conditions of life and crossing
- Fertility of varieties when crossed and of their mongrel offspring not
universal
- Hybrids and mongrels compared independently of their fertility
- Summary
Chapter IX On the Imperfection of the Geological Record
- On the absence of intermediate varieties at
the present day
- On the nature of extinct intermediate varieties; on their
number
- On the vast lapse of time, as inferred from the rate of deposition
and of denudation
- On the poorness of our palaeontological collections
- On
the intermittence of geological formations
- On the absence of intermediate
varieties in any one formation
- On the sudden appearance of groups of
species
- On their sudden appearance in the lowest known fossiliferous strata
Chapter X On the Geological Succession of Organic
Beings
- On the slow and successive appearance of new
species
- On their different rates of change
- Species once lost do not
reappear
- Groups of species follow the same general rules in their
appearance and disappearance as do single species
- On Extinction
- On
simultaneous changes in the forms of life throughout the world
- On the
affinities of extinct species to each other and to living species
- On the
state of development of ancient forms
- On the succession of the same types
within the same areas
- Summary of preceding and present chapters
Chapter XI Geographical Distribution
- Present distribution cannot be accounted for
by differences in physical conditions
- Importance of barriers
- Affinity of
the productions of the same continent
- Centres of creation
- Means of
dispersal, by changes of climate and of the level of the land, and by
occasional means
- Dispersal during the Glacial period co-extensive with the
world.
Chapter XII Geographical Distribution
(Continued)
- Distribution of fresh-water productions
-
On the inhabitants of oceanic islands
- Absence of Batrachians and of
terrestrial Mammals
- On the relation of the inhabitants of islands to those
of the nearest mainland
- On colonisation from the nearest source with
subsequent modification
- Summary of the last and present chapters
Chapter XIII Mutual Affinities of Organic Beings:
Morphology: Embryology: Rudimentary Organs
- Classification, groups subordinate to groups
- Natural system
- Rules and difficulties in classification, explained on
the theory of descent with modification --
- Classification of varieties
-
Descent always used in classification
- Analogical or adaptive characters
-
Affinities, general, complex and radiating
- Extinction separates and defines
groups
- Morphology, between members of the same class, between parts of the
same individual
- Embryology, laws of, explained by variations not
supervening at an early age, and being inherited at a corresponding age
-
Rudimentary Organs; their origin explained
- Summary
Chapter XIV Recapitulation and Conclusion
- Recapitulation of the difficulties on the
theory of Natural Selection
- Recapitulation of the general and special
circumstances in its favor
- Causes of the general belief in the
immutability of species
- How far the theory of natural selection may be
extended
- Effects of its adoption on the study of Natural history
-
Concluding remarks
