Brain Sizes Of Early Homo Erectus Fossils example essay topic

World History Human Evolution Final Copy January 19, 97 How did the early man evolve and change into the way we are today Human Evolution, the natural development of the species Homo Sapiens, or human beings. The initial man, called the Hominid was short, not intelligent, and very ape like. The next man lived in the stone age; his name was Homo Habilis. After Homo Habilis, Homo Erectus evolved. He was smarter, more efficient, and walked up-right. And he leaded to us, Homo Sapiens A lot of fossils, bones, and teeth have been found at various places throughout Africa, Europe, and Asia that proved that early man existed.

Tools made of stone, bone, and wood have also have been discovered and excavated. As a result of these discoveries, a idea of human evolution during the past 4 to 5 million years has shown. Most of the ability to make and use tools and other objects comes from the large size and complexity of the human brain. through human evolution the size of the brain has tripled. The increase in brain size may be from changes in hominid behavior. Over time, stone tools and other artifacts became more complex and the number of them increased. In addition, the geographic areas occupied by our ancestors expanded during human evolution.

They began to move into the tropical areas of Eurasia sometime after a million years ago, and into the tropical parts of these continents about 500,000 years ago. Later hominids were able to cross the water barrier into Australia. It is likely that the increase in brain size took place to permit our ancestors to be increasingly able to live in a variety of environments. The third major trend in hominid development is the decrease in the size of the face and page 1 teeth. All of the apes are equipped with large teeth tha were bigger than humans. The earliest hominid remains had great teeth that project slightly, but those of all later hominids show a great decrease in size.

With these changes is a reduction in the size of the face and jaws. As the teeth became smaller and the brain expanded, the face became smaller and its position changed. Between 7 and 20 million years ago, early apelike animals were greatly spread out on the African and, later, on the Eurasian continents. Although many fossils, bones and teeth have been found, the way of life of these mammals, and their evolutionary alikeness to the living apes and humans are still a question to scientists.

None of the fossils apes give signs of being related directly towards us. The fossils for human evolution begins with Australopithecus. Fossils of this primate have been discovered in a lot of sites in eastern and southern Africa. The genus seems to have become extinct about 1.5 million years ago and were found 4 million years ago.

All the australopithecines walked on two legs and gave the appearance of hominids. Their teeth, jaws, and brain size are different from themselves and force a separation into four groups; afarensis, africanus, robust us, and boise i. The earliest australopithecine is afarensis, which lived in eastern Africa between 3 and 4 million years ago in Ethiopia and in Tanzania. Afarensis had a brain size a little larger than chimpanzees. Some of them had dog teeth longer than later hominids. No tools have been found with afarensis fossils.

Between about 2.5 and 3 million years ago, afarensis evolved into a later australopithecine, africanus. Known from sites in southern Africa, africanus had a brain similar to afarensis. As with afarensis, no stone tools have been found with africanus fossils. Many scientists believe that there was an evolutionary split that led to robust australopithecines, africanus evolved into the group Homo. This must have happened between 1.5 and 2 million years ago.

Fossils from this time show a mixture of traits. Some Page 2 have large brains and teeth. Others have small, Homo-sized teeth and also small australopithecine brains. Skulls and jaws from this period have been placed in the category Homo habilis, meaning skillful because of the fossils that were found with stone tools. The earliest evidence of stone tools comes from sites in Africa dated to about 2.5 million years ago. By 1.5 to 2 million years ago, sites in eastern Africa include many stone tools, but also animal bones with scratch marks that experiments show were left by knife marks.

This shows that by this time early hominids were eating meat. Evidence of a large-brained, small-toothed man known as Homo Erectus was found 1.5 million years ago. Homo Erectus grew into the tropical areas of the Old World, and at the end of its evolution, into the warmer parts of Asia. A lot of archaeological sites from the time of Homo Erectus show an advancement in toolmaking than was found at the earlier sites. At the cave site of Peking man in north China, there is proof that fire was used. These studies suggest that hominid behavior was becoming more advanced and efficient.

Throughout the time of Homo Erectus the movements in human evolution continued. The brain sizes of early Homo Erectus fossils are larger than those of previous hominids. Later, Homo Erectus skulls were within the size of Homo Sapiens. Between 200,000 and 300,000 years ago, Homo Erectus evolved into Homo Sapiens. Although placed in the same species, these early Homo Sapiens are not the same in looks with modern humans. New evidence tells that modern man, Homo Sapiens, first appeared more than 90,000 years ago.

There is disagreement with scientists on whether the hominid fossils show a relation to the first appearance of Homo sapiens to humans. The Neandertals (named from the Ne ander Valley in Germany) occupied some parts of Europe and the middle east from 100,000 years ago until about 35,000 to 40,000 years ago, when they disappeared. The arguement over the Neanderthals also asks the question of the origins of human populations, or races. Human populations are shown by a lot of physical differences.

Most Page 3 of these differences show adaptations to environmental conditions. The Neandertals and other early Homo sapiens are seen as descending from Homo erectus and are ancestors to modern humans. Other scientists see racial differences n as a recent occurance. The features of the Neandertals are a low, sloping forehead and a large face without a chin. They are too primitive for them to be considered the ancestors of modern humans.

According to this theory, the beggining's of modern humans can be found in Southern Africa or the Middle East. Evolving 90,000 to 200,000 years ago, these humans then spread to all parts of the world, supplanting the local, earlier Homo sapiens populations. In addition to som fossil finds from southern Africa, support for this theory comes from comparisons of DNA, a DNA form inherited only from the mother, taken from women distributing ancestors. These studies suggest that humans derived from a single generation in sub-Saharan Africa or southeastern Asia.

Because of the tracing through the material line, this work has come to be called the Eve hypothesis; its results are not accepted by most anthropologists, who consider the human race to be much older. Whatever the outcome of this disagreement, the evidence shows that early Homo sapiens groups were highly efficient at exploiting the sometimes harsh climates of Ice Age Europe. Further, for the first time in human evolution, homini nes began to bury their dead deliberately, the bodies sometimes being accompanied by stone tools, by animal bones, and even by flowers. Although the features of today's people did not change human history, some changes did take place. In addition to the first appearance of the cave art of France and Spain, some anthropologists said that it was during that time when language came about. About 10,000 years ago, one of the most important events in human history took place, plants were farmed, and soon after, animals were used.

This made it possible for humans to Page 4 civilize. Every thing we know we got from fossils, but we still don't know enough. The future fossil discoveries will allow scientists to know what we don't about human evolution. making advanced and new tools, and increasing our knowledge will help anthropologists find the best locations for fossil hunting more precisely. In the years ahead this will result in an enormous increase in the understanding of human evolution. Page 5.