EARLY HISTORY OF SEXUAL SELECTION THEORY.

Abstract

Darwin distinguished two forms of selection on the basis of how the differential reproduction of individuals is affected. Natural selection is differential reproduction of individuals in the context of survival or ordinary reproductive endeavors such as finding a mate of the right species and sex. Sexual selection, on the other hand, results from competition for mates. The sexual competition may involve fights, searching ability, or courtship contests to coax choosy individuals to mate. Evolution by Sexual Selection Theory is a timely contribution, because after a long period of neglect, sexual selection is receiving a great deal of attention from biologists. The book reprints many of the scientific papers which were important in the development of sexual selection theory and the controversies surrounding the theory prior to 1900. It is more than a compilation of papers and excerpts from papers. The editor, C. J. Bajema, provides bibliographies and informed, interpretive commentaries for each section of the historical period covered. These commentaries include excerpts from Darwin's diary and from his correspondence with colleagues, which bring the reader closer to the ideas that were important in shaping the thinking of Darwin and other eminent natural historians of the time. The book is divided into five historical periods. Part I contains 10 papers dealing with sexual selection theory before Charles Darwin. For me, the highlights of this section are papers by J. Chardin (1686), S. S. Smith (1787), and J. Prichard (1813), which suggest that human standards of beauty vary among races, and that via mate selection these differences may account for the evolution of racial differences in morphology. This was an idea that Darwin later developed in detail in his major work on sexual selection, The Descent of Man and Selection in Relation to Sex. Part II contains Darwin's writing during the period 1837-1858 when he formulated the theory of sexual selection. Darwin's first summary of his theory of evolution by selection, the Pencil Sketch of 1842, contains a paragraph on sexual selection which reveals that he had already divided the causes of sexual selection into the performance of males in male-male combat and the ability to charm females. Bajema points out