On the Origin of Species

On the Origin of Species is about Natural Selection and Survival of the Fittest

Acclimatisation

Summary

Difficulties on Theory

Diversified and Changed Habits

Organs of Extreme Perfection and Complication

Organs of little apparent importance

Instinct

Slave-making instinct

Cell-making instinct of the Hive-Bee

Instincts that are Opposed to Natural Selection

Hybridism

The Sterility of Hybrids

Laws governing the Sterility of first Crosses and of Hybrids

Causes of the Sterility of first Crosses and of Hybrids

Hybrids and Mongrels compared, independently of their fertility

Summary of Chapter

The Imperfection of the Geological Record

Weathering

The Geological Succession of Organic Beings

Extinction

The Forms of Life changing almost simultaneously throughout the World

The mutual affinities of extinct and living species

Variation under Domestication

Summary of the preceding and present Chapters

The Effects of Geographical Distribution

Geographical Distribution

Means of Dispersal

Means Dispersal during the Glacial period

Means Dispersal during the Glacial period

Means Dispersal during the Glacial period

Geographical Distribution

The Inhabitants of Oceanic Islands