Paleomagnetic dating method teenage dating etiquette
They discovered the fossils were approximately 1.977 million years old, which predates the earliest appearances of traits specific to the human lineage the earliest undisputed predecessor of modern humans.
[10 Things That Make Humans Special] "As the fossil record for early human ancestors increases, the need for more accurate dates is becoming paramount," said researcher Robyn Pickering at the University of Melbourne in Australia. "The fossils demonstrate a surprisingly advanced but small brain, a very evolved hand with a long thumb like a human's, a very modern pelvis, but a foot and ankle shape never seen in any hominin species that combines features of both apes and humans in one anatomical package," said researcher Lee Berger, a paleoanthropologist at the University of Witwatersrand in Johannesburg, South Africa.
[See images of human ancestor] Two key specimens were discovered — a juvenile male as developed as a 10- to 13-year-old human and an adult female maybe in her late 20s or early 30s.
The species is both a hominid and a hominin — hominids include humans, chimpanzees, gorillas and their extinct ancestors, while hominins include those species after might fit on the family tree, researchers pinned down the age of the fossils by dating the calcified sediments surrounding them with advanced uranium-lead dating techniques and a method called paleomagnetic dating, which measures how many times the Earth's magnetic field has reversed.
The fossils' mix of human and primitive traits found in the brains, hips, feet and hands make a strong case for it being the immediate ancestor to the human lineage, scientists report in the Sept. The fossils included remains of a male juvenile (whose cranium is shown here) along with a female of the same species, who was likely in her 20s or 30s. Oard In my articles on ice cores, I reinterpreted the annual layers in the middle and lower portions of the GISP2 core as subannual layers, based on a Flood–Ice Age model, incorporating warm oceans, cooling continents and high levels of atmospheric particulates from volcanic activity.