Google marks the 41st anniversary of the discovery of Lucy, a skeleton dated at 3.2 million years old which was the oldest known example of a bipedal primate and a crucial stepping stone between apes and Homo sapiens. The ancient skeleton was discovered by a team of archaeologists working in Ethiopia in 1974.
Google's Doodle in the UK page shows a simplified version of the March of Progress, which is the common illustration of human evolution. It shows three moving characters, with a walking Australopithecus afarensis strategically placed in between an ape and a human being. It shows how Lucy's discovery filled the gap between the two.
Archaeologists Donald Johanson and Tom Gray found 47 bones, which although not complete, gave them enough information about the species to give an indication of the transition to Homo sapiens. Based on the skeleton's pelvic structure, it was deduced the skeleton belonged to a female.
Lucy was then named after Lucy in the Sky with Diamonds, after the Beatles song that was playing back at their camp. The uniqueness of Lucy was that although she had many of the characteristics of chimpanzees, she primarily walked upright. Lucy was the earliest example of such a primate.
Before her discovery, scientists had speculated that bipedalism - one of the key difference between the Homo genus and Pan - came alongside the development of larger brains, but Lucy proved otherwise. Her brains was barely larger than those of chimpanzees.
Lucy's species, known as , is believed to have lived between 3 million and four million years. Lucy's bones are housed in a museum in Ethiopia.