Fitness and adaptation are fundamental characteristics of plant and animal species, enabling them to survive in their environment and to adapt to the inevitable changes in this environment. This is true for both the genetic resources of natural ecosystems as well as those used in agricultural production.

A unique exchange between leading animal breeders and evolutionary geneticists

Modelling Fitness.- Defining Fitness in Natural and Domesticated Populations.- Genetic Architecture of Reproductive Fitness and its Consequences.- Fitness Traits in Animal Breeding Programs.- Discussion.- Maintaining Fitness.- Maintaining Genetic Variation in Fitness.- Spherical Cows Grazing in Flatland: Constraints to Selection and Adaptation.- Maintaining Fitness by Within Breed Selection.- Discussion.- The Genetic Basis of Adaptation.- Some Evolutionary Consequences of Niche Construction with Genotype-Environment Interaction.- Genotype by Environment Interaction in Farm Animals.- Drosophila and Selection in Nature: From Laboratory Fitness Components to Field Assessments.- Discussion.- Strategies for Managing Diversity.- Strategies to Exploit Genetic Variation While Maintaining Diversity.- Managing Genetic Diversity, Fitness and Adaptation of Farm Animal Genetic Resources.- Livestock Genetic Resources: Preserving Genetic Adaptations for Future Use.- Discussion.- Concluding Summary.- Stuart Barker's Contributions to Population Genetics and Animal Breeding: Exploring Fitness, Evolution and Animal Genetics.