Description:The study of the history of life encompasses the origins of species to their demise: evolution and extinction. Based on studies of the fossil record, this book examines the directionality of evolution--so called evolutionary trends--a fundamental aspect of life history that has received comparatively little attention in recent times. In addition to describing evolutionary trends, from the intraspecific level to macroevolutionary changes in a range of invertebrate and vertebrate organisms, this book sets out to explain just why organisms have evolved in the direction that they have.