With the help of researcher Sabudo Boraru (right), anthropologist Chris Campisano, of Arizona State University, takes samples from the fossil-filled Ledi-Geraru project area in Ethiopia. The jawbone was found nearby. Courtesy of J Ramón Arrowsmith hide caption

itoggle caption Courtesy of J Ramón Arrowsmith

An example of a human precision grip — grasping a first metacarpal from the thumb of a specimen of Australopithecus africanus that's thought to be 2 to 3 million years old. T.L. Kivell & M. Skinner hide caption

itoggle caption T.L. Kivell & M. Skinner

Farming helped fuel the rise of civilizations, but it may also have given us less robust bones. Leemage/UIG via Getty Images hide caption

itoggle caption Leemage/UIG via Getty Images

Rocky Juarez of the U.S. gets punched in the face in July 2010 by Jorge Linares of Venezuela during their WBA Fedelatin lightweight title fight in Las Vegas. Some researchers believe the human face evolved to take punches — without, of course, the boxing gloves. Steve Marcus/Reuters/Corbis hide caption

itoggle caption Steve Marcus/Reuters/Corbis

Our popular image of Homo erectus as the proto-guy who whose human-like traits all emerged at once needs overhauling, some anthropologists say. Sylvain Entressangle/Science Source hide caption

itoggle caption Sylvain Entressangle/Science Source

Signs of tuberculosis have been found in ancient Egyptian mummies, such as this one in London's British Museum. Klafubra/Wikimedia.org hide caption

itoggle caption Klafubra/Wikimedia.org