Course:ARCL 140 Summer 2020/TermProject Group 15
Evolution of the Human Diet
Contributors & Roles
Site 1: Jessica Yuen
Site 2: Amy de Boer
Site 3: Daria Hammond
Site 4: Rosabelle Carlos
Map
Site 1: Olduvai Gorge (-2.98957° N, 35.355391° E)
Site 2: Nariokotome III (4.15861° N, 35.90854° E)
Site 3: Spy Cave (50.4802° N, 4.6745° E)
Site 4: Çatalhöyük (37.6664° N, 32.8257° E)
Introduction
The genus Homo has adapted and evolved to get to where modern Homo sapiens are today. From adapting to climatic changes to utilizing the materials around them to create tools of various uses, these have all played a role in the evolution of brain size which in turn affect diet and how we process foods. Homo habilis, Homo erectus, Homo neanderthalensis, and Homo sapiens will be analyzed to observe the biological and cultural changes that occurred at each species stage that resulted in changes in diet and created new innovations such as cooking.
Studying how Homo diets have evolved over the years can give us valuable insight into the behaviours and mental capabilities of these evolving species. Early humans began as simple plant eating organisms but once meat was consistently introduced into the diet, the extra energy was important in supporting a larger brain as seen in Homo erectus (Antón, 2003). From there, new technologies such as stone tools, hunting strategies, cooking, and agriculture further supported the costs of encephalization, and led to the eventual success of Homo sapiens. The evolution of the human diet illustrates the morphological and behavioural changes necessary to transition to a diet that supported encephalization in our early human ancestors.
Four sites representing Homo habilis, Homo erectus, Homo neanderthalensis, and Homo sapiens have been used to explore the evolution of human diet. Olduvai Gorge is located in northern Tanzania. At this site, many hominin specimens were excavated and some belonged to the Homo habilis. Stone tools were also recovered which provides evidence for biological and cultural innovations of Homo habilis (Albert, 2015). The Nariokotome III site is home to the “Turkana Boy”, an almost complete Homo erectus skeleton near Lake Turkana, Kenya. The smaller teeth of this fossil and others of its genus indicate that Home erectus ate a wider and tougher range of foods than their ancestors (Unger, 2011). The Spy Cave is a rich palaeolithic site located in Namur, Belgium. The analysis of the Homo neanderthalensis teeth discovered at this site indicates that the Neanderthals had a wide and energy-rich diet, depending heavily on large-game animals and sources of plant protein (Henry et al. 2011). The evidence of cooked food within the teeth tartar also showed us that the Neanderthals were increasingly relying on cooking to facilitate the consumption and digestion of their food (Henry et al. 2011). Lastly, Çatalhöyük is located southeast of Konya, Turkey and is one of the best-preserved Neolithic sites. The ruins of this community showcase how modern Homo sapiens' have transitioned from wild to domesticated food sources and the advancements in food processing skills and technology (Atalay & Hastorf, 2006).
Site 1: Olduvai Gorge
Author: Jessica Yuen
Location: Olduvai Gorge is located in northern Tanzania, to the east of the Ngorongoro Crater Highlands and to the west of Serengeti National Park in the Eastern Rift Valley (Albert, 2015). The latitude and longitude are (-2.98957° N, 35.355391° E).
Age: 1.75-1.85 BP
Context
The first excavation occurred in 1913 but the site became famous in 1959 when Mary Leakey discovered a skull that belonged to Paranthropus boisei later known as "Nutcracker Man" or "Olduvai Hominid 5" (OH5) (Albert, 2015). Since, many fragments and bones were discovered and Olduvai Gorge became an important paleoanthropological site where intensive research is conducted to better understand the human lineage. The Plio-Pleistocene basin of Olduvai was split into seven formations: Beds Ⅰ to Beds Ⅳ, Masek Beds, Ndutu Beds, and Naisiusiu Beds (Albert, 2015). When Homo habilis first inhabited the area, the highly saline-alkaline paleo-Lake expanded and contracted due to the wet and dry climate cycles (Albert, 2015). About 1.3 million years ago, the lake disappeared and was replaced with small ponds and marshlands. The vegetation in the area was mostly wooded vegetations during Middle and Upper Bed Ⅰ; evidence later shows that trees and short grass became more prevalent, marshlands were growing, and vegetation was more diverse which was associated with fresh-water pools (Albert, 2015).
History
Olduvai Gorge has been an important paleoanthropological site where new hominid species were discovered from the 1950s to 1970s. In August of 1995, a set of hominin maxilla with complete dentitions was discovered and excavated by Agostino Venance and A. Cushing through picking at deposits near Trench 57 near Naisiusiu (Clarke, 2012). The fossils were grouped into OH65 (Clarke, 2012). During excavation, the tool used to pick the maxilla was accidentally shattered into three parts: right posterior maxilla, left posterior maxilla, and the anterior maxilla (Clarke, 2012). The broken pieces were super glued back together carefully to ensure that the specimen is preserved. Despite the shatter, the maxilla remains in fairly good shape except for its thinned-wall and small cracks near the surface of the nasoalveolar clivus (Clarke, 2012). Additionally, there were over 18000 fragments of bones and teeth that were excavated (Johansen et al. 1987). Tooth enamel is one of the most reliable techniques in measuring water excretion, diet, and water intake of an animal because the enamel is resistant against chemicalization (Van der Merew et al. 2008).
Relevance
The bones that were found at the site included maxillary, calvarial, mandibular, radial, humeral fragments, femoral and tibial fragments (Johansen et al. 1987). The OH65 showed features belonging to Homo habilis (Clarke, 2012). The features that distinguish Homo habilis (OH65) from Australopithecus were the wide and short U-shaped palate, long and straight canines, broad and flat infranasal surface of the maxilla, and the large roots of the cheek teeth (Clarke, 2012).
The incisor-molar index indicated that Homo habilis were in between chimpanzees with a large incisor-molar index and orangutans with an intermediate incisor-molar index (Ungar, 2011). This index indicated that H. habilis ate grass, plants, and meat as well (Ungar, 2011). Another supporting evidence is the microwear pit-scratch ratio. This ratio showed association with a diet of hard and tough foods (Ungar, 2011). Although tooth size in H. habilis does not seem to decrease immensely, the occlusal area is shown to be reduced. The larger the cheek tooth area, the more surface area there is to process large amounts of food. The slightly smaller incisors and molar teeth implies that there is less selective pressure for large teeth with the increasing usage of stone tools. Stone tools can help increase the surface area of the food allowing for less mechanical breakdown required in the mouth (Ungar, 2011).
At this site, there is evidence of stone tool usage (Toth & Schick, 2009). The animal bones found had cut marks on it suggesting that there had been deliberate hacking or fracturing of bones. The animal bones were presumably cracked open to expose the bone marrow which contained fatty acids and calorie dense source of protein. Other stones found at Oldowan sites and outside the site are evidence that Homo species travelled and transported these tools. Moreover, the existence and creation of stone tools are an indication of manufacturing skills in early Homo, further pushing for encephalization (Toth & Schick, 2009).
There are many other skeletal models, including OH7 and OH62, that show different parts of the anatomy that has evolved. The differences in each model demonstrates that all the adaptations do not occur at once, but instead, selection for a certain feature happens one at a time and in different species (Ungar, 2011).
Site 2: Nariokotome III
Author: Amy de Boer
Location: West of Lake Turkana, Kenya (4.15861° N, 35.90854° E)
Age: 1.51-1.56 BP
Context
The KNM-WT 15000 or “Turkana Boy” fossil is the most complete Homo erectus fossil ever discovered. It was found by Kamoya Kimeu in August of 1984 near Lake Turkana in Kenya. While most fossils are found on the east side of the lake at the Koobi Fora formation, this fossil was discovered on the west, 5 km inland from Lake Turkana by the Nariokotome river. This site was later named Nariokotome III (NK3). The age of this site was determined via isotopic dating, mainly by the K-Ar method on the volcanic material in the tuffaceous beds. The age of four tufts surrounding the fossil was taken and used to determine that the age of this fossil is between 1.51-1.56 Ma (Walker & Leakey, 1993).
Today, Nariokotome is a large stream that flows into Lake Turkana and always has water, even in the dry seasons. It is home to small troops of vervet monkeys who occupy the middle stretches. At the time of the death of the “Turkana Boy”, the area was most likely a floodplain marsh, with narrow belts of trees bordering the site. Small juvenile fish fossils were discovered indicating a shallow, heavily vegetated habitat of short duration (Walker & Leakey, 1993).
History
NK3 was established after Kamoya Kimeu discovered a piece of hominid cranial vault on the slopes of the Nariokotome river in August 1984. Sieving operations began a week later and most of the cranium was discovered, followed by more parts of the juvenile skeleton. The excavations were halted in September due to lack of funds. They resumed the next year after the find was published and then the missing teeth were recovered. The third and fourth years produced a few more bones, but nothing was discovered the fifth year. Excavation was stopped in 1988. Over the course of the excavation, 425 square metres were exposed, higher than average compared to other digs (Walter & Leakey, 1993).
Relevance
The discovery of the “Turkana Boy” fossil was crucial in enhancing our understanding of early human morphology. It is the most complete Homo erectus fossil found. However his age at time of death differs from the dental and skeletal records. Determining age, height, and weight was difficult because of our limited understanding of Homo erectus growth patterns. It was eventually estimated that age-at-death was around 8 years according to dental structure analysis while skeletal records indicate an age-at-death around 15 years (Ruff & Burgess, 2015).
The dental remains of this fossil and other Homo erectus fossils are important in understanding the diet and consequent lifestyles of this species. Home erectus had smaller molars, cheek teeth, and incisors. Processed foods require less chewing, so larger incisors and molars are no longer necessary. The cheek teeth in Homo erectus have values approaching those of modern humans. This could be a way to slow down the digestion process or reduce dental crowding in a shorter jaw. As well, there is a broader range of microwear texture complexity which indicates a consumption of a wider variety of foods and tougher foods than the hominins that came before Homo erectus (Unger, 2011).
Furthermore, it is hypothesized that the much larger brains of Homo erectus required a more nutritious diet to support the energetic costs of this organ. It is suggested that this energy-rich diet consisted of animal meat and marrow, honey, and underground tubers (Antón, 2003). While the evidence for the use of fire to cook their food comes after Homo erectus, the presence of tools is a good indicator that meat was an important, but not exclusive shift in the evolving hominin diet. As well, the narrow bi-iliac breadth of the “Turkana Boy” pelvis reflects a significant decrease in gut size due to the “Expensive Tissue Hypothesis” (Aiello & Wheeler, 1995).
Site 3: Spy Cave
Author: Daria Hammond
Location: Namur, Belgium (50.4802° N, 4.6745° E)
Age: 36,000 years BP
Context
The Spy Cave is a paleolithic site located in the village of Spy in Namur, Belgium, about 18m above the Orneau River (Naito et al. 2016). It is known for the discovery of three Neanderthal skeletons (Naito et al. 2016). The cave opens southwest at the foot of a rocky outcrop, consisting of a main chamber and two corridors (Naito et al. 2016). Today, the area enjoys a temperate climate (Naito et al. 2016). In the time of the Neanderthals, the area was thought to be intensely cold, however it is difficult to determine the palaeoenvironment that existed here because there were several fauna-bearing levels identified during excavation (Prison et al. 2012).
The Cave of Spy provided archaeologists with fossils such as Neanderthal skeletons, animal bones, and Mousterian artefacts that allowed them to better understand the Neanderthal lifestyle.
History
Spy Cave is a prehistoric site in Belgium (Pirson et al. 2012). Discovered in 1866, it was excavated several times by amateur collectors. However, no significant fossils were discovered until 1886, where two human skeletons were found and later identified as Homo neanderthalensis (Fernández-Jalvo & Andrews 2019). Since then, 24 new remains have been identified as belonging to this group (Pirson et al. 2012). From these remains was identified another Neanderthal individual, thought to be a young child (Crevecoeur et al. 2010). Many extinct animal remains, such as the woolly rhinoceros, the woolly mammoth, the cave bear, and the cave hyena were found, as well as several Mousterian artefacts (Fernández-Jalvo & Andrews 2019). Since these excavations were undertaken by both scientific institutions and amateur archaeologists, much of the discovered material is dispersed across Belgium. There was also a lack of accurate information on much of the material found, so identifying the context of certain fossils and artefacts has been compromised.
Relevance
The analysis of the Neanderthal teeth found in Spy Cave was crucial in clarifying our understanding of the Neanderthal diet. It was traditionally known that Neanderthals consumed large quantities of meat, specifically mammals such as the woolly rhinoceros, wild sheep, reindeer, mammoth, and horses (Weyrich et al. 2017). Analysis of the teeth found in Spy Cave, however, demonstrates that Neanderthals also consumed a variety of plant foods, and their teeth showed the unique pattern of wear associated with hunter-gatherer groups (Henry et al. 2011; Clement et al. 2012). This means that Neanderthals had a diverse diet and were exploiting many resources in their environments.
Demonstrated by the tools and animal bones found at Spy Cave, Neanderthals exhibited advanced hunting strategies, and were able to take down large herbivores with hafted weapons (Paskey & Cisneros, 12). This differs from other archaic humans in the sense that their advanced tools and robust bodies allowed them to kill their own prey (Paskey & Cisneros, 12). Additionally, analysis of the Neanderthal teeth tartar found at Spy Cave showed that they were regularly consuming plant foods, such as grass seeds, legumes, roots, and mushrooms (it should be noted that the Neanderthal diet varied depending on where the population was located) (Henry et al. 2011). Some of the consumed plants and meat even showed evidence of having been cooked (Henry et al. 2011). Evidence that demonstrates Neanderthals were using fire to cook food is difficult to find, so this discovery was crucial in clarifying our understanding of their lifestyle. The use of fire to cook food was an important milestone in the evolution of the human diet, “[lowering] the costs of digestion, and [decreasing] exposure to food-borne bacteria” (Henry 2017). This means that the Neanderthals were advanced in their methods of food preparation, cooking the foods available to them in such a way that increased their digestibility and nutritional quality (Henry et al. 2011).
While cooking their food made it easier to digest, this change can also be associated with the decrease in dentition and gut size present in many archaic humans (Luca et al. 2010). This increase in dietary nutritional quality, resulting from the aid of cooking, could also be linked with an increase in brain size (Luca et al. 2010). Cooking allowed tougher fibers to soften, thereby simplifying the challenging process of eating and chewing raw food (Luca et al. 2010). The energy that would have been used to consume raw food could then be saved and used to support brain growth (Luca et al. 2010). So, the use of fire to cook food and the high-caloric diets brought by this and high-levels of meat consumption can be associated with the encephalization of the human species.
Site 4: Çatalhöyük
Author: Rosabelle Carlos
Location: Southeast of Konya, Turkey (37.6664° N, 32.8257° E)
Age: 9,350- 7,900 years BP
Context
Çatalhöyük is a 9,000-year-old Neolithic site located in the middle of the Konya plains 260 km south of Turkey’s capital city, Ankara. This site consists of two archaeological mounds: the Eastern mound, dating back to 7,400-6,200 BC, and the Western mound, dating back to 6,200-5,200 BC, both 20 meters in height and situated on an inactive alluvial fan in the Konya Basin which was active during the Neolithic (Fairbairn et al., 2002). Seed and charcoal data reveal that during its time of occupation, Çatalhöyük was most likely surrounded by herbaceous marshes punctuated with steppe woodland (Fairbairn et al., 2002). In conjunction with the cultivation of rich soil from the neighboring Çumra region and the average annual precipitation of the area, this site displays characteristics that would have supported agriculture during the Neolithic.
While it is not the largest or oldest Neolithic site to exist, it is one of the best-preserved, providing archaeologists with valuable information on how modern Homo sapiens adapted to agriculture and sedentary life during the early Holocene epoch.
History
Initial excavation of Çatalhöyük, led by James Mellaart, began in 1961 and lasted until 1965. Forty houses, as well as figurines, pottery and wall art, were discovered during this period, providing insight on the evolution of human culture and symbolism (Atalay & Hastorf, 2006). The mud-brick buildings, in particular, have interior features such as hearths and ovens, detailing certain cooking practices and rituals (Atalay & Hastorf, 2006). It was not until 1993 that excavations were resumed under the direction of Ian Hodder, one of Mellaart's students, who worked with Turkish and international teams. Hodder and his team were able to uncover a lot about the Neolithic town and its culture through flora and fauna remains, burial sites, and the architectural layout of the buildings, up until 2018 when his archaeological permit ended. In July 2012, Çatalhöyük became a UNESCO World Heritage Site.
Relevance
Modern Homo sapiens' transition from foraging to agriculture, and their overall increase in behavioural flexibility, is evident in the adaptation of diverse diet and food preparation skills by those who occupied Çatalhöyük. Isotope analysis of Çatalhöyük inhabitants (470 complete human skeletal remains and an additional 272 partial individuals) reveal that men and women had similar diets, children were weaned around the age of three, and available food was influenced by what was in season (Larsen et al., 2019). To identify their diet, stable carbon isotope ratios were used to uncover the types of plants they ate while stable nitrogen isotope ratios documented which animals they consumed (Larsen et al., 2019). In regards to meat, domesticated cattle and caprines, such as goats and sheep, made up a substantial part of their diet, along with various other non-domesticated sources of protein including hares, deer, fish, and shellfish, all revealing evidence of butchery (Larsen et al., 2019).
In addition to meat, Çatalhöyük inhabitants also ate wild and domesticated dried fruits, seeds, and cereals (Atalay & Hastorf, 2006). Archaeobotanical remains at Çatalhöyük provide a record of how its inhabitants relied mostly on cereal crops such as glume wheat as well as other crops such as rye, lentils, peas, and bread wheat (Larsen et al., 2019). Cereals were a dietary staple because they were easy to store for later consumption (evident through their built in storage rooms and usage of baskets) and they were versatile, often prepared as bread or porridge (Larsen et al., 2019). This showcases their highly advanced food processing skills and their refined understanding of tools and fire as result of encephalization and behavioural flexibility to their environment. There is evidence of grinding food using slabs, grilling, baking, and roasting using ovens (Atalay & Hastorf, 2006). Their most commonly used cooking technique was stone boiling, whereby a ball of clay was heated in an oven then placed in a basket filled with water (Atalay & Hastorf, 2006).
Their mud-brick buildings reveal not just their cooking practices, but also the role that food plays in fostering community. The layout of the houses ensured that pathways and spaces were placed in a way that allowed those sitting near the oven to participate (Atalay & Hastorf, 2006). Additionally, there are central platforms built near the oven, implying that socializing and bonding occurred in the presence of food (Atalay & Hastorf, 2006). Like today, eating and cooking helped to maintain communal and familial relationships. In the wake of agriculture and settlement, populations have increased, and thus, culture and social interactions have become significantly complex and cumulative, making food more than physical nourishment, but a "social glue" (Atalay & Hastorf, 2006).
Conclusion
The archaeological sites of Olduvai Gorge, Nariokotome III, Spy Cave, and Çatalhöyük all provide valuable insight into the evolution of the human diet. Each site provides us information about the diets and lifestyles of different members of the genus Homo. The bones found at Olduvai Gorge showed that Homo habilis was increasingly relying on stone tools as a means to facilitate access to foods, decreasing the challenge of chewing and consumption, leading to the evolution of smaller teeth (Ungar, 2011). The “Turkana Boy” fossil, found at Nariokotome III shows the further reduced dentition of Homo erectus, as well as their nutritious, energy-rich diets that supported the costs of encephalization (Antón, 2003). The teeth found at Spy Cave demonstrates that Homo neanderthalensis were utilizing fire as a means to cook food, facilitating digestion and saving energy to support further brain growth (Henry et al. 2011). Finally, the Homo sapiens fossils discovered at Çatalhöyük showed the shift from a nomadic, foraging lifestyle to that of an sedentary, agricultural lifestyle, demonstrating their advanced food processing skills and understanding of tools and fire.
These four sites effectively follow the evolution of the Homo diet, allowing for a deeper understanding of their cognitive capacities and behavioral adaptations. With the introduction of energy-rich foods and an increase in tool use and cooking techniques, energy spent on chewing and digesting decreased, allowing for brain growth to be supported and resulting in the reduction of gut and dentition size (Luca et al. 2010). Encephalization has led to the development of cognitive faculties, the expansion of culture, and the creation of new innovations that have helped increase fitness: hunting strategies, stone tools, cooking, and agriculture. With the introduction of domesticated food sources and other new food processing skills, Homo sapiens have been able to expand exponentially, allowing for the rapid development and accumulation of symbolic culture (Larsen et al., 2019). Analyzing the Homo diet is essential to understanding the rise of encephalization, morphological changes, and cultural advancements that have subsequently led to characteristics that define modern humans today.
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