Population biology is a branch of biology that focuses on the study of the distribution, abundance, and dynamics of populations of organisms. It involves studying factors such as birth rates, death rates, immigration, and emigration to understand the factors that influence population growth and decline. Population biology also looks at how populations interact with their environment and other species, such as predators, prey, or competitors. By studying population biology, scientists can gain insights into the mechanisms that drive evolution, species interactions, and the ecological processes that shape the natural world.