Google Doodle celebrates early human ancestor

Google Doodle on Tuesday celebrated the 41st anniversary of the discovery of 'Lucy'-- the 3.2 million year old skeleton which helped scientists understand the evolution of apes into humans.

'Lucy' belonged to an extinct species called Australopithecus afarensis. The great ape lived between 3.9 and 2.9 million years ago, and comes from the family of hominids to which the human species homo sapiens also belong.

Though only 40% of her skeletal remains were dug out, the discovery helped scientists understand how apes progressed into humans who walk on two feet -- a crucial step in our evolution.

Lucy had many similarities with chimpanzees, but the skeleton showed that she primarily walked upright. Bipedalism is seen as one of the key distinctions between homo sapiens and chimpanzees.

The slightly-built Lucy stood about three-and-a-half feet tall, with a mixture of ape and human features -- including long dangling arms but pelvic, spine, foot, and leg bones suited to walking upright.

The fossil was unearthed in Ethiopia in 1974 by paleontologist Donald C Johanson. That night, inspired by repeated playings of the Beatles hit "Lucy in the sky with diamonds" at a celebratory party, researchers named it 'Lucy'.

The doodle on Google which celebrates her discovery shows a chimpanzee evolving into an Australopithecus afarensis and finally into a human.

Lucy's size gives her away as a female as later fossil discoveries established that A. afarensis males were quite a bit larger than females.

A number of factors point to Lucy being fully grown. For one thing, her wisdom teeth, which were very human-like, were exposed and appear to have been in use for a while before her death.

"In addition, the sections of her skull -- separated in children -- had grown together," a National Geographic report said.

Lucy's bones are kept in a museum in Ethiopia.