Evolution, Second Edition, provides a basic understanding of the complex mechanisms that cause biological evolutionary change. The book presents the most current ideas on the evolution and heredity as fundamental characteristics of life; and the origin and evolution at the population level; and the origin and evolution of new populations. The latest ideas on genetic materials, genetic drift, and human evolution are integrated with the principles of population genetics, the interactions of organisms with their environments, and with the concepts of natural selection. The book emphasizes both the origin of isolating mechanisms and evolution above the species level as relatively unexplored and challenging areas for further investigation.