In 1961, geologists at the University of California at Berkeley used a new technique called potassium-argon dating to accurately place the species, whose scientific name had been changed to Paranthropus boisei, in history. According to this groundbreaking method, which involves dating the rocks surrounding the specimen, the skull was 1.75 million years old—four times as old as previously thought and 750,000 years older than the accepted time frame for all of human history.
In 1974, researchers in the Afar region of Ethiopia discovered “Lucy,” an astonishingly complete three-million-year-old A. africanus skeleton. Lucy could clearly walk upright and was considered our oldest ancestor for a time. More recently, fossil finds have pushed the date of our earliest ancestor back further, to between five million and six million years ago, and in 2002, French paleontologist Michel Brunet announced the discovery of the oldest species yet, the six- to seven-million-year-old Sahelanthropus tchadensis. Brunet found Toumai, as the oldest hominin fossil ever found has come to be known, in the Djurab Desert of northern Chad.
In the 1960s, when potassium-argon dating was developed, paleontology began to go high-tech. For the first time, fossils older than 50,000 years could be dated. Genetic technology also came into play that decade, and today it is revolutionizing the study of human origins.
Vincent Sarich and Allan Wilson of the University of California at Berkeley were pioneers in the application of genetics to paleoanthropology in the 1960s. Their comparisons of chimpanzee and human DNA showed that the chimp lineage split from our common ancestor five million years ago. At the time, the findings caused an uproar. Anthropologists, who believed that humans and chimps diverged 15 million years ago, rejected the theory.single page
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.