Book contents
- Frontmatter
- Contents
- Preface
- Introduction
- 1 From Lamarck to population genetics
- 2 Overdevelopment of the synthetic theory and the proposal of the neutral theory
- 3 The neutral mutation-random drift hypothesis as an evolutionary paradigm
- 4 Molecular evolutionary rates contrasted with phenotypic evolutionary rates
- 5 Some features of molecular evolution
- 6 Definition, types and action of natural selection
- 7 Molecular structure, selective constraint and the rate of evolution
- 8 Population genetics at the molecular level
- 9 Maintenance of genetic variability at the molecular level
- 10 Summary and conclusion
- References
- Author Index
- Subject Index
6 - Definition, types and action of natural selection
Published online by Cambridge University Press: 05 August 2012
- Frontmatter
- Contents
- Preface
- Introduction
- 1 From Lamarck to population genetics
- 2 Overdevelopment of the synthetic theory and the proposal of the neutral theory
- 3 The neutral mutation-random drift hypothesis as an evolutionary paradigm
- 4 Molecular evolutionary rates contrasted with phenotypic evolutionary rates
- 5 Some features of molecular evolution
- 6 Definition, types and action of natural selection
- 7 Molecular structure, selective constraint and the rate of evolution
- 8 Population genetics at the molecular level
- 9 Maintenance of genetic variability at the molecular level
- 10 Summary and conclusion
- References
- Author Index
- Subject Index
Summary
Meaning of natural selection
For a proper appraisal of the neutral theory, it is essential to have a correct understanding of the role which natural selection plays in changing and maintaining gene frequencies in natural populations. Therefore, I shall briefly discuss the definition, types and actions of natural selection.
In the Introduction of The Origin of Species, Darwin (1859) states:
As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.
Although much progress has been made in biology since Darwin's time, his theory of natural selection still remains as the only scientifically acceptable theory to explain why organisms are so well adapted to their environments. A large part of population genetics may be regarded as an attempt to treat the action of natural selection and its consequences in quantitative terms (based on genetics and using the method of biometry).
- Type
- Chapter
- Information
- The Neutral Theory of Molecular Evolution , pp. 117 - 148Publisher: Cambridge University PressPrint publication year: 1983