Evolution__3rd_Edition

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Figure 1.8
(a) Ronald Aylmer Fisher (1890–1962) in 1912, as a Steward
at the First International Eugenics Conference.
Fisher, Haldane, and Wright created
a synthesis of Darwinism and
Mendelism. The synthesis began
with population genetics ...
CHAPTER 1 / The Rise of Evolutionary Biology 15
(b) J.B.S. Haldane (1892–1964) in Oxford, UK in 1914.
(c) Sewall Wright (1889–1988) in 1928 at the University
of Chicago.
R.A. Fisher is particularly important. Fisher demonstrated there that all the results
known to the biometricians could be derived from Mendelian principles.
The next step was to show that natural selection could operate with Mendelian
genetics. The theoretical work was mainly done, independently, by R.A. Fisher, J.B.S.
Haldane, and Sewall Wright (Figure 1.8). Their synthesis of Darwin’s theory of natural
selection with the Mendelian theory of heredity established what is known as neo-
Darwinism, or the synthetic theory of evolution, or the modern synthesis, after the title of
a book by Julian Huxley, Evolution: the Modern Synthesis (1942). The old dispute
between Mendelians and Darwinians was ended. Darwin’s theory now possessed what
it had lacked for half a century: a firm foundation in a well tested theory of heredity.
The ideas of Fisher, Haldane, and Wright are known mainly from their great summary
works all written around 1930. Fisher published his book The Genetical Theory of
Natural Selection in 1930. Haldane published a more popular book, The Causes of
Evolution, in 1932; it contained a long appendix under the title “A mathematical theory
of artificial and natural selection,” summarizing a series of papers published from 1918
onwards. Wright published a long paper on “Evolution in Mendelian populations” in
1931; unlike Fisher and Haldane, Wright lived to publish a four-volume treatise (1968–
78) at the end of his career. These classic works of theoretical population genetics
demonstrated that natural selection could work with the kinds of variation observable
in natural populations and the laws of Mendelian inheritance. No other processes are
needed. The inheritance of acquired characters is not needed. Directed variation is not
needed. Macromutations are not needed. This insight has been incorporated into all
later evolutionary thinking, and the work of Fisher, Haldane, and Wright is the basis for
much of the material in Chapters 5–9.