Sex And Evolution

This text provides an elementary level discussion of recent theory relating to the evolutionary and adaptive aspects of reproductive behaviour. The relation between ultimate and proximate levels of explanation is the major theme of the book. Two new chapters in this edition incorporate findings from recent research and there is also new material on humans, physiology, and development. Sex and reproductive behaviour are examined from an evolutionary comparative perspective and numerous empirical studies and examples are cited.

This book explores the relationship between various types of reproduction and the evolutionary process. Starting with the concept of meiosis, George C. Williams states the conditions under which an organism with both sexual and asexual reproductive capacities will employ each mode. He argues that in low-fecundity higher organisms, sexual reproduction is generally maladaptive, and persists because there is no ready means of developing an asexual alternative. The book then considers the evolutionary development of diverse forms of sexuality, such as anisogamy, hermaphroditism. and the evolution of differences between males and females in reproductive strategy. The final two chapters examine the effect of genetic recombination on the evolutionary process itself.

Essays on the genetic aspects of sex, genetic recombination, and genetics and the evolutionary process by molecular biologists, population geneticists, and ecologists.

Sex is the queen of problems in evolutionary biology. Generations of researchers have investigated one of the last remaining evolutionary paradoxes: why sex exists at all. Given that sexual reproduction is costly from an evolutionary point of view, one could wonder why not all animals and plants reproduce asexually. Dozens of contemporary hypotheses attempt to explain the prevalence of sex and its advantages and predict the early extinction of fully asexual lineages. The major theme of this book is: what is the fate of animal and plant groups in which sex is lost? Initial chapters discuss theory behind asexual life: what major disadvantages do asexual groups have to face, what are the genetic and ecological consequences and what does this theory predict for more applied aspects of asexual life, for example in agricultural pests, diseases as well as in cultural crops such as grapes. Cases studies in many animals (focusing on both invertebrates and vertebrates) and plants reveal parallel, but also singularly novel adaptations to the absence of meiosis and syngamy. And last but not least, are asexuals really doomed to early extinction or do genuine ancient asexuals exist? This book assembles contributions from the most important research groups dealing with asexual evolution in eukaryotes. It is a milestone in research on parthenogenesis and will be useful to undergraduate as well as graduate students and to senior researchers in all fields of evolutionary biology, as the paradox of sex remains its queen of problems.

The question of why organisms reproduce sexually is still a matter of controversy. In this account, Professor Maynard Smith considers the selective forces responsible for the origin and evolution of sexual reproduction and genetic recombination, using quantitative population genetics arguments to support his ideas. The relative importance of individual and group selection processes are also considered. the aim is to give a clear statement of the theoretical issues, and present enough of the evidence to show what kinds of facts are relevant. It is hoped that where crucial evidence is missing, experimentalists and field workers may be encouraged to collect the relevant data. The author does not claim to solve all the problems he raises, but this clear and well-argued account should provide stimulating reading for advanced undergraduate students and research workers in evolutionary theory.

Few things come more naturally to us than sex—or so it would seem. Yet to a chimpanzee, the sexual practices and customs we take for granted would appear odd indeed. He or she might wonder why we bother with inconveniences like clothes, why we prefer to make love on a bed, and why we fuss so needlessly over privacy. Evolution and Human Sexual Behavior invites us into the thought-experiment of imagining human sex from the vantage point of our primate cousins, in order to underscore the role of evolution in shaping all that happens, biologically and behaviorally, when romantic passions are aroused. Peter Gray and Justin Garcia provide an interdisciplinary synthesis that draws on the latest discoveries in evolutionary theory, genetics, neuroscience, comparative primate research, and cross-cultural sexuality studies. They are our guides through an exploration of the patterns and variations that exist in human sexuality, in chapters covering topics ranging from the evolution of sex differences and reproductive physiology to the origins of sexual play, monogamous unions, and the facts and fictions surrounding orgasm. Intended for generally curious readers of all stripes, this up-to-date, one-volume survey of the evolutionary science of human sexual behavior explains why sexuality has remained a core fascination of human beings throughout time and across cultures.