Human Evolution
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Human Evolution By: William Henderer Table of Contents Introduction………………………………………………………………..…page 3 Chapter One: Body Changes…………………………………………………page 4 Chapter Two: Tools…………………………………………………………...page 8 Chapter Three: Culture………………………………………………………page 11 Chapter Four: Migration…………………………………………………….page 16 Chapter Five: Anthropology………………………………………………...page 20 Conclusion…………………………………………………………………..page 23 Works Cited…………………………………………………………………page 24 Images Cited………………………………………………………………...page 25 2 Introduction I chose this topic because I have always been interested in why humans are so much more advanced than other species. I have definitely enjoyed doing the research and writing the paper. It was difficult at times, but I pulled through and got it done. The biggest questions I had were, “Why do we need to evolve?”, “How did we become so advanced?” and “How similar are we compared to each other?”. It took a lot of research to answer these questions, but I eventually found the answers. While researching I came across a theme to human evolution. Not many people realize this, but human evolution makes humanity what it is currently. When we look deeper into our origins, human evolution can vastly broaden our perspective. We can look at things around us and realize how long it took humans to develop things. It makes us think more about what seem to be simple things and piques our curiosity about what it means to be human. 3 Chapter One Body Changes Human fossil records have helped us understand early humans. The first beings that closely resembled modern humans were living approximately one million years ago. The first hominids*, also known as human ancestors, lived in Africa about eight to six million years ago. Current fossil records go back only seven million years. The fossil records show immense amounts of information about the brain. The percent of body space that the brain takes up has grown from 1.2% to 2.75%. Chimpanzees have a low, small brain case. However, some early humans had long and large brain cases. Neanderthals, one of the more recent hominids, had large skulls and brains that were even bigger than modern humans. Just because neanderthals had a bigger brain, this did not mean they were more intelligent. *any member of the group consisting of all modern and extinct humans and great apes (including gorillas, chimpanzees, and orangutans) and all their immediate ancestors. Brain size between species varied quite a bit. Larger brains can overheat easily which may have caused hair loss. Interestingly enough, homo 4 heidelbergensis, who lived around 250,000 to 1,000,000 years ago, had a similar size brain to a modern human. In the past three million years, human brain size has nearly tripled. This could be the result of eating more protein on a regular basis. Brain size has dramatically changed human intelligence. Some hominids* developed adaptations to the environment in which they lived. Neanderthal heads were lower, longer, and had round eye sockets with heavy brows, and large teeth. Paranthropus robustus, who lived two to one million years ago, had a ridge on the top of its skull, strong muscles for chewing, and large grinding teeth. Australopithecus afarensis, who lived three to two million years ago, had small canine teeth, thick cheek teeth and thicker bones. Homo erectus, who lived 2,500,000 to 250,000 years ago, had strong chewing muscles, a dome shaped head, and flat wide face. All of these species fared well with these adaptations to the environment. *any member of the group consisting of all modern and extinct humans and all their immediate ancestors, specifically species more closely related to modern humans than to chimpanzees. Humans' skulls have changed dramatically from those of apes. Chins receded at ausrulopithuceus afarensis. Modern humans have a bone that keeps the tongue in one place letting humans make all kinds of sounds. The modern human skull is higher, more rounded with a flat face, and teeth and jaws are much smaller than apes. 5 The rest of the body changed immensely as well. Neanderthals had humongous bones, inflated chests, and were quite strong. Chimpanzees have longer arms than legs, unlike modern humans who have longer legs than arms. Australopithecus afarensis had big and strong arms. Like modern humans Australopithecus afarensis had an s shaped back, broad knees, and forward facing toes. These are only a few changes. Hominins' bodies started to look somewhat similar to modern humans 1.8 million years ago. Modern humans were the only living hominin species 30,000 years ago. Australopithecus garhi, who lived around 2.5 million had long legs which gave us the legs we have today. Our legs helped us survive, they helped us run from predators and go places faster. Evolution is supposed to help us reproduce, and that is how longer legs helped. They stayed with our ancestors, who passed them down to us. Arm and leg length has grown quite a bit relatively recently. Humans still have not changed that much in the past 100,000 years. It is harder for modern humans to reproduce because humans’ big heads put quite a bit of strain on our smaller pelvises. Neanderthals were probably able to survive the ice age because their small limbs lost heat slowly. Humans’ bodies have had some major changes in structure over the years. 6 Chapter Two Tools As humans became more complex their tools became increasingly more complex with them. Tools looked very different, depending on where and when they were made. Most tools did one of the following: grind, chop, or cut. In different regions, tools would look different because the culture that used the tools may have used them in different ways. Gorillas do not use tools as much as chimpanzees, but they still will crack a nut with a rock. Chimpanzees on the other hand, will actually take a leaf and use it to get water out of a tree, they also will use leaves to shelter from the rain. Neanderthals hunted with spears and axes. There were various kinds of tools for many circumstances. Many species used different tools for hunting. Neanderthals mostly ate meat which they had to hunt for, also, they would eat fish and plants. Homo habilis cut open nuts and shells with rocks. They also used tools to crush bones for the fatty bone marrow inside. Tools were not only used for hunting. Sometimes humans would be buried with special tools. Many tools could help reach things. After the Ice Age, people started to farm and made tools to do so. Flint sickles were used to harvest crops. Small shovels were made to dig holes in the ground. People also made places to put crops to save for the winter. Tools were complex and hard to make. By taking a stone and hitting it against another stone you could chip off bits of rock and make a tool. Different types of rocks were better for other tools. A stone could be fastened to a shaft to make a thrusting spear. It can take a long time to make one tool. 7 There are four main steps in making a stone tool. The first step is burying the rocks and building a fire on top of them. The next step is to chip off flakes of stone. After that the rocks would be pushed down upon so the rocks shape into what tool the maker wants it to be. Finally use bones to make fine sharp tips. The type of rock used is important. Early stone tools were just rock grabbed off the ground. Tools were made from many different types of rocks, some better than others. Sometimes people would travel ten miles to find good rocks like obsidian. It can be hard to tell the difference between normal rocks and tools, however if the rock is not native to the area then it is probably a tool. Sometimes scientists put together pieces of chipped rock back together to make the original stone. Some rocks were valued deeply and for some strange reason, the largest tools were found in China, nobody knows why. 8 Chapter Three Art There were two different periods throughout prehistoric art. The early period, which is associated with hand stencil spray painting ( with pigment not paint) and drawings of large animals. The later period consisted mostly of migrating humans on a stylistic background. The early period is dated about 39,000 years old. While the late period is dated to 10,000 years ago. In different time periods there were different art styles, this is still true today. Paint was essential for drawing all kinds of animals and people. People would work extremely hard to get paint. Haematite, limonite, and specularite can produce a wide variety of colors for paint. People would crush the minerals to get colored powder which they would use to paint. Some paint was specifically used as body paint. Some Scientists believe that color coding might have been a method of communication. Many people painted cave art in Europe. Over 90 different caves containing paintings have been found, but more are to be discovered. In caves people used red, yellow, brown, and black paint. Most of this cave painting happened 40,000 years ago. Cave painting is probably the most well known ancient painting that people did. 9 Art can show scientists what was around in the past. During December of 1994, three explorers came together to explore caves near Avignon, France. They found over 300 cave paintings of animals that were over 32,000 years old. Art like this can tell researchers about the animals that lived long ago without needing to find the bones. Using carbon dating they can find out when the painting was made thus telling them when the animals lived.