Humanity’s First Ancestor is 2 Million Years Old, Skull Fragment Reveals
The story of human evolution is a contested one. A basic narrative with certain elements of truth exists in the popular realm which is that the earliest human beings evolved from apes. That stage of evolution was not an overnight process, and took millions of years to reach its conclusion, including several evolutionary and biological mechanisms that we take for granted today. Now, scientists say our first ancestor walked around Lake Turkana, Kenya two million years ago! Early man and modern man are both part of the Hominidae family. Modern humans are homo sapiens .
To fill in the blanks on this massive timeline of the various genus evolutions, a new study by scientists from Arizona State University has revealed some exciting information, which was recently published in the journal Nature Communications . The study focused on a skull fragment found in the 1970s in Kenya, previously dated to 1.78 million years old. However, the new research show that this first ancestor of ours is, in fact, 2 million years old!
This skull bone is that of a homo erectus , which literally translates into “upright man,” the first hominid with a similar body structure and behavioral mechanism as the modern human .
According to Heritage Daily , study lead author Ashley Hammond said, “ Homo erectus is the first hominin that we know about that has a body plan more like our own and seemed to be on its way to being more human-like. It had longer lower limbs than upper limbs, a torso shaped more like ours, a larger cranial capacity than earlier hominins, and is associated with a tool industry–it’s a faster, smarter hominin than Australopithecus and the earliest Homo.”
The latest study from Arizona State University suggests this is the skull fragment fossil of our first ancestor, which is 2 million years old! Source: Nature Communications
The Challenges of Dating Our First Ancestors at Lake Turkana
“Homo erectus was around for almost 2 million years and lived alongside several other hominid species at different periods of time,” Professor Hammond told SYFY WIRE . “East Turkana is one place where we find multiple hominid species overlapping, so this field location has the potential to provide more information about how these species coexisted sympatrically. I’d love to know more about how Homo erectus interacted with other hominids.”
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Homo erectus is our oldest ancestor with more human than ape-like characteristics, including significant brain development, bipedalism, and mastery over tools.
The discovery in question – KM-ER 2598 – was discovered at Lake Turkana , in East Turkana, Kenya, in 1974. At that time, without the kind of technology at the disposal of archaeologists and paleontologists today, dating this discovery was difficult because most known homo erectus fossils were dated to several hundred thousand years later, based on “outdated” dating technologies.
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To put it into context, the initial discovery of the Turkana skull and other remains was carried out without GPS or satellites or location tracking of any sort. All discovered fossils in the 1970s were merely identified with pinpricks and handwritten serial numbers. The standard practice of dating bone fossils was achieved by dating the rocks found immediately around the fossil.
The reassembled skeleton of Turkana Boy, which was discovered on Lake Turkana in 1984. It was dated to 1.5-1.6 million years ago. (Claire Houck from New York City, USA / CC BY-SA 2.0 )
Radiometric Dating and Understanding the New Discoveries
The team from Arizona State University carried out a process by radiometrically dating the rocks around the skull fossil, when it was first discovered back in 1974.
Even at that time in 1974, standard methods dated the fossil to 1.9 million years old, which was only surpassed by another homo erectus discovery in South Africa dated to 2 million years old. A whole swarm of researchers argued against the age of the East Turkana discovery, arguing that the rocks could have drifted due to wind or water, and were probably from a younger fossil deposit.
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At the site, thorough radiometric testing by Arizona State University researchers was carried out to determine that there were no younger rocks near KM-ER 2598 (the skull fragment fossil). Radiometric results showed that the skull, based on the stones found near it, was 1.88-1.9 million years old.
Subsequently, a group of nearby rocks, which were identical to the ones at the original site, were dated to 2 million years ago.
Foot and pelvis fossils , likely from the same time, were also found. But it was unclear if they were from the same individual, i.e., our first ancestor.
“It is likely that they are the same individual since they were found so close together, but we cannot prove this,” Hammond told SYFY WIRE . “If researchers are able to find additional footbones or pelvic material from early Homo erectus, this would allow critical comparisons of the anatomy that might strengthen our claim.”
Top image: Modern human and Homo erectus man compared. Source: AlienCat / Adobe Stock
By Rudra Bhushan
Hammond, A.S., Mavuso, S.S., Biernat, M. et al . 2021. New hominin remains and revised context from the earliest Homo erectus locality in East Turkana, Kenya . Nature Communications 12 , 1939. Available at: https://doi.org/10.1038/s41467-021-22208-x.
Heritage Daily. 2021. Study cements age and location of hotly debated skull from early human Homo erectus . Available at: https://www.heritagedaily.com/2021/04/study-cements-age-and-location-of-hotly-debated-skull-from-early-human-homo-erectus/138681.
Liberatore, S. 2021. Skull bone reveals human ancestor homo erectus lived 2 million years ago , making it the oldest specimen on record . Available at: https://www.dailymail.co.uk/sciencetech/article-9476413/Skull-bone-reveals-human-ancestor-Home-erectus-lived-2-MILLION-years-ago.html.
Rayne, E. 2021. Who started to look human go way back… like 2 million years back . Available at: https://www.syfy.com/syfywire/homo-erectus-oldest-ancestors-look-human.