Out of Africa
One of the most prevalent questions in the human psyche is “where did we come from?”. People have different evolutionary theories about the exact movements and locations of early Homo sapiens, though it is widely accepted that Africa was our species’ birthplace.
Numerous fossils of human remains have been found around eastern Africa, with the oldest being from modern day Ethiopia and named Omo I. Scientists have been able to see their ages by the environmental fingerprint of surrounding sediments. Previously, scientists thought the Omo I remains dated back to less than 200,000 years ago.
Older than we thought
A research team, led by the University of Cambridge, has been able to update this using ancient volcanic ash records. “The fossils were found in a sequence, below a thick layer of volcanic ash that nobody had managed to date with radiometric techniques because the ash is too fine-grained,” said the paper’s lead author Dr. Céline Vidal.
They continued: “Each eruption has its own fingerprint — its own evolutionary story below the surface, which is determined by the pathway the magma followed. Once you’ve crushed the rock, you free the minerals within, and then you can date them, and identify the chemical signature of the volcanic glass that holds the minerals together.”
We have a lot more to learn about our evolution
By comparing this signature to the layers in which the fossils were found, it was concluded that this early Homo sapiens life could be dated back to at least 230,000 years ago. These findings, published in Nature, may be able to assist evolutionary biologists in more accurate prediction of our history and place in the universe.
“We can only date humanity based on the fossils that we have, so it’s impossible to say that this is the definitive age of our species,” said Vidal. “The study of human evolution is always in motion: boundaries and timelines change as our understanding improves. But these fossils show just how resilient humans are: that we survived, thrived and migrated in an area that was so prone to natural disasters.”
Source study: Nature – Age of the oldest known Homo sapiens from eastern Africa