The Ultimate Colonists

Human ancestors settled into one ecosystem after another

The Stone Age was rough on community life, at least among animals trying to make a living in Africa. A range of species would move into a local habitat–gazelles, zebras, pigs, people, you name it–and take a few generations to establish the web of interactions that characterizes an ecosystem. After a millennium or so, dramatic climate shifts would then radically remodel the habitat, motivating the residents to leave.