The Evolution of Anisogamy: A Fundamental Phenomenon Underlying Sexual Selection

Darwin identified the existence of separate male and female gametes as one of the central mysteries of evolutionary biology. 150 years later, the question of why male gametes exist remains an intriguing puzzle. In this, the first book solely devoted to the evolution of anisogamy, top theorists in the field explore why gamete dimorphism characterizes nearly all plants and animals. Did separate male and female gametes evolve as a result of competition, or does anisogamy instead represent selection for cooperation? If disruptive selection drove the evolution of anisogamy, with male gametes focused on search and fusion, and female gametes provisioning the new zygote, why do some algal species continue to produce gametes of a single size? Does sperm limitation, or escape from infection, better explain the need for extremely small, highly mobile sperm? Written by leaders in the field, this volume offers an authoritative and cutting-edge overview of evolutionary theory.

Table of Contents:
Introduction Paul Alan Cox; 1. The origin and maintenance of two sexes (anisogamy), and their gamete sizes by gamete competition Geoff A. Parker; 2. The evolutionary instability of isogamy Hiroyuki Matsuda and Peter A. Abrams; 3. Contact, not conflict, causes the evolution of anisogamy Joan Roughgarden and Priya Iyer; 4. Nucleo-cytoplasmic conflict and the evolution of gamete dimorphism Rolf F. Hoekstra; 5. Adaptive significance of egg size variation of aquatic organisms in relation to mesoscale features of aquatic environments Kinya Nishimura and Noboru Hoshino; 6. Gamete encounters David B. Dusenbery; 7. Evolution of anisogamy and related phenomena in marine green algae Tatsuya Togashi and John L. Bartelt; Index.

About the Author :
Tatsuya Togashi is Professor of Marine Biology at Marine Biosystems Research Center, Chiba University, Kamogawa, Japan. Paul Alan Cox is Executive Director of the Institute for Ethnomedicine, Jackson Hole, Wyoming, USA.

Review :
'This is a fascinating and authoritative collection shedding new light on one of the most fundamental challenges in evolutionary biology. Charles Darwin, who puzzled over the evolution of anisogamy, would much enjoy reading this book.' Simon A. Levin, Princeton University 'The mysteries of sex intrigue everyone, from all walks of life, but most laypeople are unaware that there has not always been sex. Sex, involving gametes of very unequal size (anisogamy) - one large and sessile and one tiny and mobile - evolved from a simpler mating system with two equal, small gametes (isogamy). Why? This book addresses this important question from all angles, empirical to theoretical. Contrasting explanations are argued in clear but rigorous detail, making this book ideal for advanced undergraduate and graduate seminars, as well as study by professionals. Plants, with their diversity of present-day mating systems, play a major role in the book which will help to broaden student's perspectives by showing that interesting biology is not restricted to animals!' Brent D. Mishler, University of California, Berkeley 'The origin of sex was a key innovation in the evolution of eukaryotes. It was followed by an equally important key innovation, the origin of anisogamy, the functional differentiation of gametes into two types (male and female). This fundamental evolutionary phenomenon is treated in this book. Whereas there is a large body of literature on sex, anisogamy has found less attention. This fine volume is a collection of theoretical papers on essential aspects of anisogamy and sexual selection written by outstanding biologists. The introductory chapter gives a first glimpse into the fascinating history of the discovery of the evolution of anisogamy based on a wide array of clever biological questions.' Peter K. Endress, University of Zurich '… not only a must have for those interested in the specific topic but also comes highly recommended for anyone interested in sexual selection … both informative and provocative … it is likely that readers will leave with a firm understanding of the topic as well as several hypotheses of their own stemming from the reading. It is my hope that this volume will find itself in the hands of many evolutionary biologists and psychologists and that this impactful and pertinent idea will further shape our understanding of sexual selection.' American Journal of Human Biology