A video of players wearing white and black clothes passing a basketball is shown, and the task is to count the number of passes made by the white shirt team. As the minute passed, a person dressed as a gorilla appeared and patted him on the chest, but surprisingly, half of the participants in the experiment did not notice it because they were counting the number of passes.
Not long ago, while reading a paper on paleoanthropology published in ‘Science’, I suddenly remembered the ‘invisible gorilla’ experiment. The paper analyzed hundreds of Oldowan stone tools (stone tools), thousands of animal bones, and two molars of ancient humans excavated in Nayanga, Kenya, Africa in 2017, and was found to be about 2.9 million years old. This breaks the record of the 2.6 million-year-old Oldowan stone tool excavated from Afar, Ethiopia, which is the oldest known so far. For reference, jjikgae, which breaks one side of a stone to make a blade and uses the other side as a handle, is a typical oldowan stoneware.
Not only were these excavated from the same layer, but one molar in particular was placed in the same space as several stone tools and hippo bones with traces of butchery. Perhaps they ate the flesh attached to the bone with a sharp stone like a knife, or they split it open by striking it with a stone like a hammer and ate the bone marrow. Unexpectedly, however, it turned out that the main character of these molars was not the early Homo, but the Paranthropus, who lived at the same time.
If you look at the human evolutionary tree by limiting the time to 3 million to 1 million years ago, you can see that the humans of the genus Homo (H.) and the genus Paranthropus (P.) were the main characters. Recent discoveries put the Paranthropus lower limit at 200,000 years and the Oldowan Stone Age at 300,000 years further back than mapped. Paranthropus made Oldowan stoneware, but it seems that he did not acquire Acheulean technology. science provided
Although they have a place in the human evolutionary tree, they were ‘invisible gorillas’ to me, who was only interested in the genealogy of modern humans, Australopithecus and Homo. This is because Paranthropus, which has a more primitive appearance than Australopithecus, is a strange species that has returned to apes in some way, so there was no problem in understanding human evolution even if it was ignored. However, according to this thesis, it is highly likely that he is the main character of the oldest Oldowan stoneware, so we have no choice but to tilt our heads.
I was surprised to see the human evolution tree again. Australopithecus went extinct about 2 million years ago, but Paranthropus lived about 1 million more years before disappearing. They have held out for nearly a million years against our direct ancestor, Homo erectus, in East and South Africa. Paranthropus, who are you?
In the first half of the 20th century, South Africa was a hotspot for paleohuman research. Fossils of Australopithecus africanus were discovered in 1924, and fossils of Paranthropus robusta were found in 1938. It can be assumed that Paranthropus had great chewing power because the sagittal crest protruding from the top of the head held the well-developed left and right temporal muscles like today’s gorillas (right). Even the size of the molars is larger than that of Australopithecus (left). Courtesy of John Fleagle
● First discovered in 1938
The story begins in South Africa in 1924. Raymond Dart, a 31-year-old professor of anatomy at the University of Witwatersrand Medical School in Johannesburg, asked students to bring fossils to them for use in lectures. After recognizing that the fossil brought back by a student as a monkey skull was an archaic human, Dart gave it the scientific name Australopithecus africanus, which means ‘southern ape of Africa’. The main character was estimated to be three or four years old, and was affectionately called “Taung child” after the name of the village he had excavated.
Robert Broom, a practicing physician and paleontologist, was spurred on by a young friend’s luck and set out to find an adult Africanus fossil. Broom, who moved to South Africa as a curator at the Transvaal Museum in 1934, succeeded in excavating an adult Africanus fossil in Sterkfontein, near Taung, in 1936. Then, two years later, he discovered a new hominid fossil in Crom Dry, also nearby. Compared to Australopithecus, it had larger jaws and molars, giving it a tougher face, which Broom gave it the scientific name Paranthropus robustus, which means ‘sturdy semi-human’.
Comparing the upper molars of Paranthropus boisei (left) with those of modern humans (right) explains why they earned the nickname ‘nutcracker’. However, as a result of analyzing the wear of the teeth, it was found that they ate almost no hard food such as walnuts, and mainly ate rough and tough foods such as grass seeds and tuberous roots. Courtesy of Arkansas
● Paranthropus habilis?
Louis Leakey, a British archaeologist born in Kenya, explored the Olduvai Gorge in Tanzania in the 1930s with his wife Mary, excavated many stone tools (the Oldowan stone tools) and persistently searched for fossils of ancient humans who might have made them. One day in 1959, Mary finally found the first human skull fossil in East Africa, and Lewis gave it the scientific name Zinzanthropus boisei, which was later reclassified as Paranthropus. Boisei is named after Charles Boyce, a miner who financed the exploration.
The boisei looks more robust than its genus, the South African robustus, especially its molars, which are the largest of any hominid ever discovered. The press made headlines about Boisey’s discovery and nicknamed him “Nutcracker Man.”
Although this fossil came from the same strata in which stone tools were found, it was hesitant to claim that it was the maker of Oldowan stone tools. This is because the appearance is also primitive, and the size of the brain is about 500cc, which is slightly larger than that of chimpanzees. But the following year, Jonathan, the eldest son of the Ricky couple, accidentally discovered the skull and jawbone fossils of an ancient human child. The couple, surprised to learn at a glance that they were closer to modern humans than boisei, also found wrist bones and hand bones nearby.
An adult foot bone was subsequently excavated, followed by another skull and jawbone three years later. As a result of the analysis, the relatively large brain and small jaw were distinctly different from Australopithecus or Paranthropus, and the structure of the hand and foot bones was similar to that of modern humans. Ricky and his colleagues identified them as early hominids of the genus Homo, and gave them the scientific name Homo habilis, which means ‘man with dexterity’. It means the people who made Oldowan stone tools excavated in this area.
Judging from the excavated strata, Olduvai’s Boisei and Habilis must have lived at the same time, and as a result of dating later, it was found that the main characters of the fossils lived about 1.8 million years ago. Nonetheless, Oldowan stone tools were considered entirely the heritage of the Habilis, and Boisei was imprinted as an ignorant hominid whose powerful teeth replaced tools. The habilis break walnuts with a stone hammer, and the boisei crush them with their molars.
Another Paranthropus fossil was discovered in Ethiopia in 1968, giving it the scientific name P. aethiopicus. After that, fossils of the same series were found in Kenya and Tanzania, and as a result of dating, it was confirmed that the species lived between 2.7 and 2.3 million years ago. Ethiophicus is most likely a direct ancestor of Boisei and Robustus. Although it cannot be concluded that the owner of the two molars excavated this time is Ethiophicus, the beginning of Paranthropus has been updated to 200,000 years and 2.9 million years ago.
The fossil distribution of Paranthropus spans East and South Africa and dates back about 200,000 years to recent fossil discoveries, from 2.9 million to 1 million years ago, spanning nearly 2 million years. Courtesy of Wikipedia
● Climate change drives evolution
In 1974, a very well-preserved fossil of an ancient human was discovered in Afar, northeastern Ethiopia. This fossil, called ‘Lucy’, was given the scientific name Australopithecus afarensis, and as a result of dating, it was found to be a human 3.18 million years ago. After that, the genealogy of human evolution connecting the genus Australopithecus and the genus Homo was established. Failing to fit in, Paranthropus fell out of the media and public attention.
Interestingly, Ethiophicus appears less robust than the boisei that came later. It probably evolved from Australopithecus, so it makes sense. In any case, about 3 million years ago, two lineages, the genus Homo and the genus Paranthropus, would have emerged from Australopithecus and went their separate ways. In this process, the original (Australopithecus) disappeared, and the remaining Paranthropus coexisted with Homo for 2 million years before becoming extinct 1 million years ago.
Many studies have shown that climate change, which began in earnest at the end of the Pliocene, was the driving force behind the above evolution. As the climate becomes drier and more volatile, the pressure on habitat and food grows, adapting in two directions. The Paranthropus series, which can feed on rough and low-nutritional plants with developed jaws, and the Homo series, which evolved to be more suitable for walking and running for a long time, and improved hunting-gathering efficiency, emerged and survived.
Meanwhile, as technology for analyzing fossil teeth developed, preconceived notions about Paranthropus were shattered. In particular, Boisei, who was nicknamed the Nutcracker, thought that he would have enjoyed eating hard-shelled fruits, but as a result of analyzing the wear marks left on the tooth surface using a confocal microscope, there were few cracks on the tooth surface enamel, and instead, there were many fine scratches. . This means that they mainly ate rough and tough foods such as grass seeds or tuberous roots. On the other hand, Robustus exhibited varying degrees of abrasion depending on the samples examined.
Meanwhile, as a result of examining the ratio of the isotope carbon 13, it was revealed that Boisei mainly ate C4 photosynthetic plants. C4 plants, which evolved to store carbon dioxide separately in hot and dry regions where water is easily lost during photosynthesis, lose the ability to prefer carbon 12 during this process, and thus have a higher rate of carbon 13 than C3 photosynthetic plants. In East Africa, where the climate changed to a hot and dry direction, C4 plants flourished, and boisei that could eat and digest them survived. On the other hand, Robustus, which lived in South Africa, where the climate was relatively mild, showed a similar isotope pattern to other genus hominins.
The results of tooth analysis taught us a lesson that we shouldn’t just look at the appearance of fossils and infer our usual eating habits. No matter how strong a jaw a gorilla may have, if it had to choose between a banana and a kudzu root, it would most likely choose a banana. The jaws and teeth of Paranthropus are a trump weapon that allowed it to survive in difficult situations where there was not much choice.
A paper was published on the 10th of the journal Science, which analyzed stone tools and animal bone fossils from 2.9 million years ago excavated in Nayanga, Kenya. The body stone from which fragments and fragments were removed is typical of Oldowan stoneware (above), and the hippo bone that came out together shows clear signs of damage that appear to have occurred when the flesh was removed (below). science provided
● Who is the true habilis?
Returning to the ‘Science’ paper, looking at the animal bones excavated along with stone tools, various herbivores such as hippos, pigs, and antelopes are included. In particular, the hippopotamus bone excavated near one of the molar teeth has intact traces of damage to stone tools. In addition, plant remains were found on the surface of the stone, which appeared to have been buried during the pounding process.
In their thesis, the authors said, “With this excavation, the first traces of slaughtering megafauna or processing plants go back at least 600,000 years.” It was a long time ago,” he wrote.
Of course, just because the main character of the molars is Paranthropus, it cannot be said that they made stone tools. It could be that early Homo humans picked up discarded items, or it could be that the Paranthropus fossil was accidentally placed in the place where they had a party. Nevertheless, judging from the excavation results of recent years, especially the discovery of stone tools used by humans (probably Australopithecus) 3.3 million years ago, it is not too much of a stretch to say that Paranthropus is the main character of the feast.
Perhaps Oldowan’s stoneware was a skill that many people of the same age could acquire. In other words, when the Boisei fossil was discovered in 1959, the Ricky couple must have been right. In fact, had it not been for the discovery of habilis fossils the following year, they might have claimed that Boisey had made Oldowan stone tools.
Perhaps the true Homo habilis, a human with dexterity, is the human race that made Acheulean stone tools that appeared shortly thereafter. Stone tools such as hand axes found in East Asian Homo erectus relics are much more sophisticated than Oldowan stone tools and are called Acheulean culture. Evidence of the first Acheulean culture was found in stone tools excavated in Kenya dating back 1.76 million years, and Acheulean stone tools dating back 1.75 million years were found in nearby Ethiopia. In other words, Homo erectus should be called habilis.
Perhaps Paranthropus’ failure to acquire Acheulean stone tool skills may be one of the reasons why it was pushed out of competition with Erectus and eventually became extinct. Thanks to Acheulean stone tools, Erectus would have greatly improved hunting efficiency and would have gained superiority in weapons in the fight against Paranthropus. Paranthropus’ huge jaws and teeth broadened the spectrum of food, but it might have prevented his brain from expanding and eventually yielded to the smart and dexterous Erectus.
※ About the author
Seokki Kang Science Columnist ([email protected]). She worked as a researcher at LG Household & Health Care Research Center and worked as a reporter at Donga Science from 2000 to 2012. Since September 2012 she has been working as a freelance writer. His own books include 《Kang Seok-ki’s Science Café》 (volumes 1 to 7) and 《In Search of the Origin of Life Science》. His translations include Antimatter, Heart Stories, and Proof: The Science of Liquor.
