Adaptation is caused by selection continually winnowing the genetic variation created by mutation. In the last ten years, our knowledge of how selection operates on populations in the field and in the laboratory has increased enormously, and this book aims to provide an up-to-date account of selection as the principal agent of evolution. In the classical Fisherian model, weak selection acting on many genes of small effect over long periods of time is responsible for driving slow and gradual change. It is now clear that adaptation in laboratory populations often involves strong selection acting ... More

Adaptation is caused by selection continually winnowing the genetic variation created by mutation. In the last ten years, our knowledge of how selection operates on populations in the field and in the laboratory has increased enormously, and this book aims to provide an up-to-date account of selection as the principal agent of evolution. In the classical Fisherian model, weak selection acting on many genes of small effect over long periods of time is responsible for driving slow and gradual change. It is now clear that adaptation in laboratory populations often involves strong selection acting on a few genes of large effect, while in the wild selection is often strong and highly variable in space and time. These results are changing our perception of how evolutionary change takes place. This book summarizes current understanding of the causes and consequences of selection, with an emphasis on quantitative and experimental studies. It includes material on experimental evolution, natural selection in the wild, artificial selection, selfish genetic elements, and selection in social contexts, sexual selection, and speciation.