MilestoneTwoATH210 (1)

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Southern New Hampshire University *

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210

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Anthropology

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Jan 9, 2024

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Milestone Two ATH210 Hominin Evolution The oldest known hominin fossil is Sahelenthropus tchadensis . S. tchadensis, or TM 266-01-060-1 , was found in 2001 in Chad but existed sometime between 6 and 7 million years ago. His fossil shows that his head was being held in an upright position, which is evidence of bipedalism (Smithsonian Institute, 2022c). The foramen magnum was located forward under the cranium, which is not seen in apes, or other primates. Anthropologists have only discovered cranial parts of S. tchadensis , so there is no other evidence of bipedalism for this species. Their brain size was slightly smaller than a chimpanzee's (Smithsonian Institute, 2022i). Lucy is one of the most famous hominin fossils to be found nearly complete. AL 288-1 is Australopithicus afarnesis and was found in 1974 in Hadar, Ethiopia. Lucy is about 3.2 million years old. Her pelvis was broad and short, and her thigh bones were pointed inward which would support holding her body upward while in bipedal locomotion. She also had long arms and curved toe bones that would allow her to climb trees (Smithsonian Institute, 2022f). Turkana Boy, KNM-WT 15000, is a Homo erectus fossil that is about 40% complete. His fossil was found in West Turkana, Kenya in 1984 but is believed to have lived about 1.6 million years ago. His long legs suggest that H. erectus could walk and run long distances, which is most likely the reason why H. erectus was spread across Africa and Asia. Turkana Boy was probably around 9 years old at the time of his death, but he was 5’3” and could have possibly grown taller as he got older. His brain size was around 880 cubic centimeters (Smithsonian Institute, 2022a). Stone tools and handaxes have also been found in this area from the same time period suggesting they made and used tools (Smithsonian Institute, 2022h). Hobbit, LB-1, was Homo floresiensis . She was discovered in 2003 in Flores, Indonesia,

and lived 80,000 years ago. Her skeleton shows that she was around 30 years old when she died, but that she was only 3’6” tall. Hobbit’s brain was only about 400 cubic centimeters (Smithsonian Institute, 2022b). But there are also tools that were found during this time and place (Smithsonian Institute, 2022d). Anthropologists believe that because this species was isolated for a long time on an island with limited resources, there was an evolutionary process that stunted their growth causing dwarfism (Chetan-Welsh et al., 2022). The fossils of Homo neanderthalensis were first discovered in 1829 in Engis, Belgium. Neanderthals lived about 400,000-40,000 years ago. Their bodies were adapted for cold environments, by having large noses to help humid or warm cold air, and they had short stocky bodies. Neanderthals also made sophisticated tools, clothing, and ornaments. Their brain sizes were the same size as modern humans (Smithsonian Institute, 2022e). Hominins have evolved greatly throughout the years. The fossils that we are looking at today can tell a lot about how modern humans have evolved. S. tchadensis can only show us cranial evidence of the species, but we can see that standing upright, and possibly bipedalism, started with this hominin because of the position of his head to his neck (Smithsonian Institute, 2022i). Lucy has shown us that she was upright and bipedal but also climbed trees. The environment and habitat influence our evolution. When we move on to Turkana Boy, the brain size of H. erectus has gotten bigger which means their skill sets have become broader and slowly becoming more sophisticated. I included H. floresiensis in evolution because although evidence shows they were descendants of H. erectus , it is like they backtracked in evolution (Chetan- Welsh et al., 2022). Their brains are half the size, and their bodies are much smaller. It is important to understand that all types of evolution are crucial to human evolution, even if it was a step backward. So far fossils of H. floresiensis have only been found in Indonesia, and they

are a prime example of an evolutionary process based on their environment (Chetan-Welsh et al., 2022). Neanderthals have also shown us an evolutionary process based on the environment because of their survival in cold conditions (Tilkens et al., 2007). More completed skeleton fossils give us more answers about evolution. We can compare fossils like Lucy, Turkana Boy, and Neanderthals to modern humans because we have more complete skeletons. These fossils all seem to be smaller in size than modern humans. But as we can see they were shorter and broader, which is how early hominins retained heat (Tilkens et al., 2007). This makes sense because early hominins lived in much colder environments. Modern humans have more modern technology to help keep us warm. The other similarities seen in my chosen fossils are the broad and short hips which help support body weight in an upright position. As for skin color, there has been evidence from DNA extracted from Neanderthal fossils that they possibly had different pigmentations based on the melanocortin 1 receptor (Lalueza-Fox et al., 2007). This is similar to modern humans because not everyone has the same skin tone. All of the models that I used are at the Smithsonian National Museum of Natural History. The fossils would need to be carefully transported in order to display them in our museum. The transportation and compensation to obtain these fossils would be very expensive. I am sure there will also be a cost of insurance for the fossils, and we would need added security on the premises. The alternative to having the real models would be replicas to take their place. Casts of these fossils could be taken, but there is always a risk of damaging the original fossil. Replicas are also not 100% accurate and can be misleading when doing research (The Paleontology Portal, n.d.). Although having the real specimen would be ideal for learning in our museum, a replica will suffice in this circumstance since it can still show us their basic stature.

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