Lucy and other members of her species, Australopithecus afarensis, lived between 3.9 and 3.0 million years ago.
They are believed to be the most ancient common ancestor, or "stem" species, from which all later hominids sprang. Estimating the age of hominid fossils is usually a painstaking, two-part process, involving both "absolute" and "relative" dating.
During the latter half of this century anthropological surveys in East Africa have made significant contributions to understanding how the human species has evolved.
In this room we explore how these scientists can reconstruct the past from their studies of the geological contexts in which fossils are found, the dating of the specimens, their comparative anatomy with extinct and living species of our taxonomic order, the Primates, and the lifeways and behavior patterns of the first members of the human family within the Primates.
Yet even this seminal K-Ar dating study was plagued by the seemingly insurmountable problem of contamination. Advances in Archaeological and Museum Science, vol 2.
The principal materials for dating East Africa hominid sites are volcanic ashes, yet many of these ashes are not deposited as primary air fall (Greek for ash).
"Relative" dating involves comparing one object to others to build a chronology.
Scientists currently don't have a technique for dating fossils like Lucy directly, but they can assign these fossils relative dates based on the age of layers of volcanic ash found above and below them.