The Origin of Species by Means of Natural Selection
On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life is a book by Charles Darwin published in 1859. It introduced the world to evolution through a process of natural selection. The main thesis was that different animal species were not independently created, and that similar species can result from natural variation followed by different survivability rates. Animals that are more adapted to their environments are more likely to survive. Alfred Russel Wallace wrote a similar theory independently, and had sent a manuscript to Darwin. Darwin also used Herbert Spencer's phrase "survival of the fittest", but then fitness has to be defined as that which survives.
Human evolution is conspicuously absent from Origin - knowing of the opposition such a suggestion would face, Darwin confined his initial speculation to nonhuman animals. He covered the topic of human evolution in a later work, The Descent of Man and Selection in Relation to Sex.
- 1 Summary
- 1.1 CHAPTER 1. VARIATION UNDER DOMESTICATION
- 1.2 CHAPTER 2. VARIATION UNDER NATURE
- 1.3 CHAPTER 3. STRUGGLE FOR EXISTENCE
- 1.4 CHAPTER 4. NATURAL SELECTION
- 1.5 CHAPTER 5. LAWS OF VARIATION
- 1.6 CHAPTER 6. DIFFICULTIES ON THEORY
- 1.7 CHAPTER 7. INSTINCT
- 1.8 CHAPTER 8. HYBRIDISM
- 1.9 CHAPTER 9. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD
- 1.10 CHAPTER 10. ON THE GEOLOGICAL SUCCESSION OF ORGANIC BEINGS
- 1.11 CHAPTER 11. GEOGRAPHICAL DISTRIBUTION
- 1.12 CHAPTER 12. GEOGRAPHICAL DISTRIBUTION--continued
- 1.13 CHAPTER 13. MUTUAL AFFINITIES OF ORGANIC BEINGS: MORPHOLOGY: EMBRYOLOGY: RUDIMENTARY ORGANS
- 1.14 CHAPTER 14. RECAPITULATION AND CONCLUSION
- 2 External Links
CHAPTER 1. VARIATION UNDER DOMESTICATION
In this chapter, Darwin motivates the case for variation and selection by illustrating the variety among the natural and domesticated plant and animal worlds. Without knowing the details of inheritance (which would be demonstrated later by Gregor Mendel, James Watson, and Francis Crick among others) he shows its implications: like breeds like. Inheritance is what breeders use to direct the variation of species to some useful means. This is done by selection; the breeders' are keenly aware of the minor differences in the offspring populations of animals and exploit them to create new varieties. The variation of species is not simply due to crossings of existing varieties. He argues this by showing examples where it is unlikely or impossible, pigeons, dogs, and talks about recent domestication. Pigeon varieties completely different in appearance from the the wild rock pigeon show traits of the wild rock pigeon when crossed. He shows, through the works of breeders, that in fact even animals within the same breed show variation of which expert breeders are aware (consciously or subconsciously) and exploit to direct the traits of the offspring. This he shows convincingly, as breeders cannot control traits directly, but can exploit variation to make new breeds because they know the traits are inherited. During Darwin's time, species was not a well-defined category: animals may be regarded as species or varieties even among prominent naturalists of the time.
CHAPTER 2. VARIATION UNDER NATURE
CHAPTER 3. STRUGGLE FOR EXISTENCE
CHAPTER 4. NATURAL SELECTION
the cycle of natural section states that a predator will gain a advantage over prey then the prey gains a advantage over the predator and so on and so forth.