FIGURE 1-16 The Course of Human Evolution The hominid brain has increased nearly threefold in relative size, illustrated here by the skulls of Australopithecus afarensis (left), Homo erectus (center), and modern Homo sapiens (right). Missing parts of the Australopithecus skull, shown in blue, have been reconstructed. The Origin of Modern Humans (p. 165), by R. Lewin, 1998, New York: Scientific American Library. Photo by Kevin O’Farrell/Concepts.