Methods dating human fossils updating mepis
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.
Though still heavily used, relative dating is now augmented by several modern dating techniques.
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content.
Furthermore, because his skull was found separated from his body, his body had probably not been buried deep beneath the soil, meaning his body was probably originally put in a shallow grave, near the river.
After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.
Carbon-14, or radiocarbon, is a naturally occurring radioactive isotope that forms when cosmic rays in the upper atmosphere strike nitrogen molecules, which then oxidize to become carbon dioxide.
Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies.
But one significant problem clouded the excitement over the discovery: The team doesn’t know how old the fossils are.
And without that age, it’s hard to know how fits into the story of human evolution, or how to interpret its apparent habit of deliberately burying its own kind.
(Any remnant of the past, not just bones, can be considered a fossil.) 3.6 million years ago, a volcano now called Sadiman puffed out a cloud of ash that blanketed the surrounding area.