Economist: Lucy's Daughter

"Knowing how that process has changed over time may shed light on the evolution of humans' superior intelligence, which relies on a long childhood."

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 Palaeoanthropology

Lucy's daughter

Sep 21st 2006
From The Economist print edition

An ancient child has been discovered

THIS is a photograph of the skull of a three-year-old girl—or a 3m-year-old girl, depending on how you count it. It was discovered, along with much of the rest of her skeleton, in the Hadar region of Ethiopia, in 2000. She belonged to a species called Australopithecus afarensis, which is believed to be ancestral to modern man. Following five painstaking years spent extracting her bones from their sandstone casing, Zeresenay Alemseged of the Max Planck Institute for Evolutionary Anthropology, in Leipzig, and his colleagues have described her in Nature. Her leg bones confirm that A. afarensis could walk upright, though her ape-like upper body and the arrangement of the semi-circular canals of her ears, which are the location of the sense of balance, suggest she also spent a lot of time climbing trees. The evolutionary transition to full-time walking, which would have freed early humans' hands for using tools, clearly came later.

Since young bones are fragile, such a complete specimen of an ancient infant is a startling find. Comparing it with adult specimens (the most famous of which is known as Lucy) should show the way that A. afarensis grew from childhood to adulthood, particularly the way the brain grew. Knowing how that process has changed over time may shed light on the evolution of humans' superior intelligence, which relies on a long childhood.

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