Tuesday, January 14, 2020

Homo Neanderthalensis – the Neanderthals

Since their discovery more than a century ago, the Neanderthals have hovered over the minds and have baffled the best-laid theories of paleoanthropologists. They seem to fit in the general scheme of human evolution, and yet they’re misfits. (Jurmain, Kilgore, Trevathan and Ciochon. p. 367) In a way they are like us the modern Homo sapiens but yet are a very different species. But the real question that needs to be answered is â€Å"why the Neanderthals were considered a different species than the Homo sapiens and what made them go extinct? † The first Neanderthal remains were discovered in the year of 1856 in Germany. This discovery of a skullcap and partial skeleton in a cave in the Neander Valley (near Dusseldorf) was the first recognized fossil human form (Smithsonian 2007b). This was the first time Neanderthal fossils were discovered, as skulls were unearthed in Engis, Belgium in 1829 and Forbes’ Quarry, Gibraltar in 1848. However; these earlier discoveries were not known as belonging to archaic forms. The type of specimen, named Neanderthal 1, consisted of a skull cap, two femora, three bones from the right arm, two from the left arm, part of the left ilium, fragments of a scapula, and ribs. When this skeleton was recovered the workers thought the bones belonged to a bear. The workers then gave the material to an amateur naturalist Johann Karl Fuhlrott, who then in turn gave the fossils to anatomist Hermann Schaffhausen. The discovery was jointly announced in 1857. In 1864, a new species was known as: Homo Neanderthalensis. These, and later, discoveries led to the idea that these remains were from the ancient Europeans who played an important role in modern human origins. The bones of over four hundred Neanderthals have been found since. The most controversial one was excavated in 1908 at La Chalpelle-aux-Saints in southeast France. This was a nearly complete skeleton of a man who would have been elderly by the Neanderthals standards. The bones were analyzed between 1911 and 1913 by the well known French paleontologist, Marcellin Boule. But unfortunately his prejudices got in the way of scientific objectivity. He described the La Chapelle- aux-Saints man, and subsequently all Neanderthals, as dull- witted, brutish and ape-like creatures who walked hunched over with a shuffling gait. Today scientists think he misjudged the Neanderthal posture because the adult male that was discovered had osteoarthritis of the spine. Also, and probably more important, Boule and his contemporaries found it difficult to fully accept that the Neanderthals would have been the ancestor of modern humans. The skull of this male, which was 40 years old when he died, is very large with a cranial capacity of 1,620cm. Typical of western European classic forms, the vault was low and long; the brow ridges are immense, with the typical Neanderthal arched shape; the forehead was low and retreating; and the face was long and projecting. The La Chapelle skeleton wasn’t a typical Neanderthal, but and unusually robust male. Who â€Å"evidently represented an extreme in the Neanderthal range of variation† (Brace et al. , 1979, p. 117). The term â€Å"Neanderthal Man† was named by an Irish anatomist William King. He named them after the Neander River Valley. Classic Neanderthal fossils have been found over a large area, from northern Germany, to Israel to Mediterranean countries like Spain and Italy, and from England in the west to Uzbekistan in the east. The first proto- Neanderthal traits appeared in Europe as early as 350,000 years ago. (Bischoff et al. 003). By 130,000 years ago, full blown Neanderthal characteristics were present. Neanderthals became extinct in Europe approximately 30,000 years ago. There is recently discovered fossil and stone-tool evidence that suggests Neanderthals may have still been in existence 24,000 years ago, at which time they disappeared from the fossil record and were replaced in Europe by modern Homo sapiens. (Rincon 2006, Mcilroy 2006, Klein 2003, Smithsonian 2007b, 2007b, 2007c). The classic Neanderthal cranium was large, long, low and budging at the sides. Viewed from the side, the occipital bone is somewhat bun-shaped. The forehead rises more vertically than that of a H. Erectus, and the brow ridges arch over the orbits instead of forming a straight bar. The Neanderthals were robust, barrel-chested, powerfully muscled. They also had a large, thick skull, a sloping forehead, and a chinless jaw. This robust skeletal structure, in fact, dominates hominin evolution from H. Erectus through all premodern forms. (Jurmain, Kilgore, Trevathan and Ciochon. p. 370). Neanderthals had a compact body of short stature. Males averaged 1. 7 m (5ft 5in) tall and an estimate to weigh 84kg (185lb), and females averaged 1. m (5ft) tall and an estimate 80kg (176lb). (Smithsonian 2007c). Neanderthals also differed from modern Homo Sapiens in that they had a low forehead, double arched brow ridge, larger nasal area, projecting cheek region, weak chin, obvious space behind the third molar, heavily-built bones, broad scapula, short lower leg and arm bones relative to the upper portions, occasional bowing of the limb bones, the hip rotated outward, a long and thin pubic bone, and large joint surfaces of the toes and long bones. (Smithsonian 2007c). Neanderthals had noses that were broad and very large. They had limb bones that were thick and had large joints which indicate they had strongly muscled arms and legs. The shin bones and forearms tended to be shorter than those of modern humans. The pelvis was wider from side to side than in modern humans and this may have slightly affected their posture. One striking feature of Neanderthals was the brain size, which in these hominins actually was larger than that of H. sapiens today. The average for contemporary H. sapiens is between 1,300 and 1,400 cm, while for Neanderthals it was 1,520cm. The large size may have been linked with the metabolic efficiency of a larger brain in cold weather. Neanderthals mostly lived in cold climates, and their body proportions are similar to those of modern cold-adapted people for example the Eskimo people. The Eskimo people also live in very cold areas, and have a larger average brain size than most other modern human populations. Neanderthals develop quite differently in their childhood than the Homo sapiens. Neanderthal children may have grown faster than modern human children. Where as modern Homo sapiens have the slowest body growth of any mammal during childhood with lack of growth during this period being made up later in an adolescent growth spurt. The possibility that Neanderthal childhood growth was different was first raised in 1928 by the excavators of the Mousterian rock-shelter of a Neanderthal juvenile. Arthur Keith in 1931 wrote, â€Å"Apparently Neanderthal children assumed the appearances of maturity at an earlier age than modern children. †(Keith, Arthur p. 346) The rate of body maturation can be inferred by comparing the maturity of a juvenile’s fossil remains and the estimated age of death. Evidence shows that Neanderthals had a complex culture although they did not behave in the same ways as the early modern humans who lived at the same time. Scholars debate the degree of symbolic behavior shown by Neanderthals as finds of art and adornment are rare, particularly when compared to their modern human contemporaries who were creating significant amounts of cave paintings, portable art and jewelry. Some researchers believe that the Neanderthals lacked cognitive skills to create art and symbols and, in fact copied from or traded with modern humans rather than create their own artifacts. The Neanderthals had a reasonably advanced toolkit classified as Mode 3 technology that was used by early members of our own species, Homo sapiens. This was also known as the Mousterian, named after the site of Le Mousteir. Near the end of the time of the Neanderthals, they began to utilize the Chatelperronian tool style similar to the blade tools of Homo sapiens. . The tools of the Homo sapiens differed from that of the Neanderthals. The tools of the Homo sapiens were much more detailed as they were made out of ivory, bones antlers, and wood. There is little evidence that Neanderthals used antlers, shell, or other bone materials to make tools; their bone industry was relatively simple. However, there is good evidence that they routinely constructed a variety of stone implements. The Neanderthal (Mousterian) toolkits consisted of sophisticated stone-flakes, task-specific hand axes, and spears. Many of these tools were very sharp. Neanderthals trimmed a flint nodule around the edges to form a disk-shaped core. Each time they struck the edge, they produced a flake, and they kept at it until the core became too small and was discarded. There is also good evidence that they used a lot of wood, although such artifacts would likely not have been preserved (Henig 2000). Chatelperronian is one of the most advanced tool style than that of the Mousterian. This occurred at about the same time as modern humans entered Europe. Many archeologists think that the Neanderthals were attempting to copy the types of tools that they observed modern humans making. Alternatively, it is possible that they may have obtained these tools by trading with the modern humans. While Neanderthals had weapons, no projectile weapons have been found. They had spears, in the sense of a long wooden shaft with a spearhead firmly attached to it, but these were not spears specifically crafted for flight. The Neanderthals used their hunting weapons for hunting prey in close proximity and usually hunted in their localized areas. Because Neanderthals had no long-distance weaponry and were mostly limited to thrusting spears, they many have been more prone to serious injury-a hypothesis supported by paleoanthropologists Thomas Berger and Erik Trinkaus (Jurmain, Kilgore, Trevathan and Ciochon, p. 376). Where as the modern Homo sapiens made use of spear-thrower and bow and arrow. With these weapons the Homo sapiens had a wider range of social contacts, perhaps permitting larger, more organized hunting parities. The Neanderthals built hearths and were able to control fire for warmth, cooking and protection. They were known to wear animal hides, especially in cooler areas. However, there is no physical evidence that Neanderthal clothing was sewed together, and it may have simply been wrapped around the body and tied. A very intriguing find was excavated a hollowed-out bear femur that contained holes that may have been deliberately bored into it. This bone was found in western Slovenia in 1995, near the Mousterian fireplace, but its significance is still a matter of dispute. Some paleoanthropologists think that it might have been a flute, while others have expressed that it is a natural bone modified by bears. Another way in which Neanderthals differed markedly from contemporary modern Homo Sapiens, Homo sapiens employed a much wider range of materials from across Europe- such as seashells from Atlantic and mammoth ivory from southern Germany. Neanderthals, by contrast, probably stayed mostly around their caves and campsites. So they did not trade like the modern Homo sapiens. They probably transported their stone materials from short distances- just a few kilometers away. This suggests that Neanderthals activity was localized and territorial. Although much has been hyped about the Neanderthal’s burial of their dead, their burials were less elaborate than those of anatomically modern humans. The interpretation of the Shanidar IV burials as including flowers, and therefore being a form of ritual burial (Solecki 1975), has been questioned (Sommer 1999). On the other hand, five of the six flower pollens found with fossil Shanidar IV are known to have had traditional medical uses, even among relatively contemporary populations. In some cases Neanderthal burials have been found with grave goods, such as bison and auroch bones, tools, and the pigment ochre. On the other hand burial of Modern Homo sapiens were more much more complex, and frequently included both tools and remains of animals (Jurmain, Kilgore, Trevathan and Ciochon, p. 378) Neanderthals occupied a range of environments across Europe and the Middle East and lived through a period of changing climatic conditions. Ice Age in Europe was interspersed with warmer periods but by 110,000 years ago average temperatures were on the decline and full glacial conditions had appeared by 40,000 years ago. There is evidence that the Neanderthals hunted big game and chemical analysis of their fossils shows that they ate significant amounts of meat supplemented with vegetation. Despite this mixed diet, nearly half of the Neanderthals skeletons studied show the effects of a diet deficient in nutrients. Researchers have long debated whether Neanderthals also included human meat in their diets. It is not always easy to determine whether the cut marks on human bones are due to cannibalism, or some other practice or even animal teeth. But in recent years new evidence has emerged that suggests that some Neanderthals may indeed have been cannibals on occasions. The cave of El Sidron in Spain yielded hundreds of Neanderthals bones with cut marks, deliberate breaks for marrow extraction, and other signs that the bodies had been butchered for flesh in the same way as animals. There is Neurological evidence for potential speech in Neanderthalensis existed in the form of the hypoglossal canal, which is a bony canal in the occipital bone of the skull. The canal of Neanderthals is the same size or larger than in modern humans, which is significantly larger than the canal of Australopithecines and modern Chimpanzees. The canal carries the hypoglossal nerve, which supplies the muscles of the tongue with motor coordination. Researchers indicate that this evidence suggests that Neanderthalensis had vocal capabilities similar to, or possibly exceeding that of, modern humans (Kay et al. 1998). However, a research team from the University of California, Berkeley, led by David DeGusta, suggests that the size of the hypoglossal canal is not an indicator of speech. His team’s research, which shows no correlation between canal size and speech potential, shows there are number of living non-human primates and fossilized australopithecines that have equal or larger hypoglossal canal. In 1997, geneticists were able to extract a short sequence of DNA from Neanderthal bones from 30,000 years ago. In July 2006, the Max Planck Institute for Evolutionary Anthropology and 454 Life Sciences announced that they would sequence the Neanderthal genome over the next two years. At roughly 3. billion base pairs, Neanderthal genome is about the size of the modern human genome. According to the preliminary sequences, 99. 7% of the base pairs of the modern human and Neanderthal genomes are identical, compared to humans sharing around 98. 8% of the base pairs with the chimpanzee. The researchers recovered ancient DNA of Neanderthals by extracting the DNA from the femur bone of a 38,000 year old male Neanderthal specimen from Vindija Cave, Croatia and other bones found in Spain, Russia, and Germany. Additionally, in 2010, the announcement of the discovery and analysis of Mitochondrial DNA from the Denisova hominin in Siberia revealed that this specimen differs from that of modern humans by 385 bases in the mtDNA strand out of approximately 16,500, whereas the difference between the modern humans and Neanderthals is around 202 bases. Groundbreaking analysis of the Neanderthal genome published in 2010 shows that modern humans and Neanderthals did interbreed, although on a very limited scale. Researchers compared the genomes of five modern humans with the Neanderthal, discovering that Europeans and Asians share about 1-4% of their DNA with Neanderthals and Africans none. This suggests that modern humans bred with Neanderthals after moderns left Africa but before they spread to Asia and Europe. The most likely location is the Levant, where both species co-existed for thousands of years at various times between 20-90,000 years ago. Interestingly, the data doesn’t support wide-scale interbreeding between the species in Europe, where it would have been most likely given their close proximity. Neanderthals persisted for hundreds of thousands of years in extremely harsh conditions. They shard Europe for 10,000 years with the Homo sapiens. Today they no longer exist. There are two main theories of why they have disappeared. The first theory says the Neanderthals interbred with Homo sapiens on a relatively large scale. Followers of this theory believe that although Neanderthals as organisms no longer exist their genes were present in early modern Europeans and may still exist today. Interbreeding diluted Neanderthal DNA because there were significantly more Homo sapiens. Neanderthals were a sub-species of Homo sapiens rather than a separate species and hence their scientific name is Homo sapiens neanderthalensis. There is quite a bit of evidence that supports this theory. There are features of Neanderthals in some Cro-Magnon (Homo sapiens) populations. For instance the discoverers of the 24,000-year-old skeleton of a modern human boy from Lagar Velho in Portugal argue that although the pelvis and facial morphology are sapiens-like, the robusticity and limb proportions are more Neanderthal-like. As the age of the skeleton is later than the time of the last known Neanderthal, these features must represent significant interbreeding and transmission of DNA between modern humans and Neanderthals. Cro-Magnon remains from Vogelherd in Germany and Mladec in the Czech Republic also exhibit a Neanderthal-like projection of the occipital bun at the back of the skull, more so than in later Homo sapiens. Various reasons have been proposed for the ‘replacement’ of Neanderthals by modern humans. Today, most theories accept that Neanderthals displayed advanced behaviors and adaptive strategies and were not sluggish brutes that stood no chance against the vastly superior Homo sapiens. Neanderthal reproductive success and survival rates appeared poor compared to Homo sapiens. Most Neanderthal remains were of individuals rarely over 30 years old and over half were children. Slightly better rates of reproductive success and childhood survival over 10,000 years could be all it took for Homo sapiens to replace Neanderthals. Neanderthals may have also lacked the adaptive nature of modern humans who had complex social networks across wide areas. Smaller populations of Neanderthals that tended to stay in limited areas may have made them vulnerable to local extinctions. The survival techniques of Neanderthals were not as developed as Homo sapiens. For instance, studies on stress and build-up of tissue in Neanderthal bones indicate they may have lacked systematic and directional planning in procuring food. This Neanderthal predominance of ‘brawn over brain’ may also be reflected in the number of skeletal injuries seen in both sexes, probably from close range hunting. Other studies show that 40% of Neanderthal remains have hypoplasia, a condition caused by lack of nutrients in early childhood. This is supported by tests on Neanderthal bone collagen which indicate that meat was very significant in Neanderthal diets to the point that they may be lacking the nutrients from other sources used by Homo sapiens, especially fresh water products and vegetable matter. Researchers also believe climate could have played a major role in Neanderthal’s extinction. New data on the glacial period that occurred from about 65,000 to 25,000 years ago (known as OIS-3) shows that it was a period of rapid, severe and abrupt climate changes with profound environmental impacts. Although Neanderthals were physically adapted to the cold, the severe changes in conditions (within individuals' lifetimes in many cases) allowed no time for populations to recover. I believe doing this research on Neanderthals has taught me a lot more than I knew. I was fascinated by the anatomical differences and similarities between the Homo sapiens and the Neanderthals. I got to learn a lot about their lifestyles, their cultures and how the Neanderthals became extinct. I was surprised to know that some Neanderthals showed evidence of cannibalism. Now having done the research on the Neanderthal, if I was asked to answer my own research question I would be able to answer it. Neanderthals were different from the Homo sapiens for various reasons. They were anatomically different than the Homo sapiens. The Neanderthals were strong and robust while the Homo sapiens today are not as robust and barrel-chested as the Neanderthals. Also the brains of the Neanderthals were larger than the Homo sapiens today. Also I found the extinction theories of the Neanderthals very interesting. I agree with the climate theory. It was mentioned as evidence that the weather was so abrupt and severe it might have affected the Neanderthals negatively leading them to go extinct. Overall this research project made me become aware of all our previous human ancestors.

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