A new study shows that ancient human-like fossils in South Africa are more than a million years older than previously thought.
The history of human evolution could be changed by the new date. It's possible that these fossils are from a species that predated theLucy fossil. Lucy's species was thought to be the best candidate for the direct ancestors of humans.
The only member of the human family that is still alive is Homo. According to previous research, the leading candidate for the progenitors of Homo may have been the genera Australopithecus.
Lucy's species of ape is called Australopithecus afarensis. Lucy was the oldest and most complete skeleton of an ancient hominin, the group that includes humans and the extinct species more closely related to humans than any other animal, according to Nature.
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The most abundant sources of Australopithecus fossils have been found in South Africa. The first known adult Australopithecus was found there in 1936. Scientists have found hundreds of hominin fossils over the years, which are usually classified as members of the speciesAustralopithecus africanus.
The bones were thought to be less than 2 million years old. The oldest known Homo fossils were found in Ethiopia. The species could not have been the direct ancestors of Homo, according to this suggestion.
Lucy's and A. africanus were thought to be descended from East Africa's A. afarensis.
There is a lot of debate about the ages of the fossils at the site. The nearly complete skeleton of Little Foot is estimated to be 3.67 million years old, according to research conducted by a group of people.
New estimates of the ages of the other hominin fossils were sought by the researchers. The bones are thought to be between 3.4 million and 3.8 million years old. It's possible that Homo could have come from South Africa and not East Africa as long thought.
It's difficult to understand the dates of the fossils. Scientists usually estimate the ages of fossils by analyzing the layers in which they are found. Attempts to date older deposits could be difficult due to the complex system of caves at the site.
Other strategies for dating the fossils include examining the bones of other animals, such as horses unearthed around the hominin fossils, or the flowstone linked with the fossil layers. The dates derived from these methods could be incorrect due to the fact that bones can shift within caves during flooding.
It is possible to date the rocks in which the fossils were found. Researchers looked at the matrix in which the fossils are embedded.
Scientists analyzed the nuclide within the rocks. Cosmic rays are high-energy particles that bombard Earth from outer space. The number of neutrons in an element's atomic nucleus varies from element to element.
When a rock is exposed at the surface, but not deep in a cave, aluminum-26 forms. The fossils within the caves can be dated by measuring levels of aluminum-26 in conjunction with another nuclide.
It was surprising to me that the new ages were so close to the old ones. There was a lot of hominins in East Africa during that time, and so all of the Australopithecus fossils fall into a narrow time period. This shows that hominins in East Africa and South Africa are related.
The new findings show that A. africanus is the same age as A. afarensis. The ape-like skull and facial features of A. africanus are more primitive than those of A. afarensis. He suggested that the two species are descended from an older common ancestor.
The older age allows more time for the South African species to evolve into later hominins. Homo could be included. We don't know if it happened or not, but it opens a window of possibilities.
John Hawks, a paleoanthropologist at the University of Wisconsin-Madison who did not participate in the study, said the controversy of the Sterkfontein fossils' ages will not be solved by the new technique.
Hawks said that the different teams need to agree on what the geology of the site is telling them. It will take a lot of work to get these different scientists to agree on what they are seeing.
Scientists who want to solve the puzzle of the ages of these bones may take part in double-blind experiments involving different groups of researchers examining the same samples, without knowing where they are from until they report their results. There is a lot of potential for researchers to use samples and methods that reinforce their ideas.
The scientists wrote about their findings in the journal.
It was originally published on Live Science
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