The Evolution of Man
The Evolution of man Describe the evolution of man Georgina Taylor 10/10/2012 Word count: 1141 ? The Evolution of Man The greatest mysteries of science, a subject which intrigues us all is how exactly the human species evolved. Evolution is the sequential process of change over periods of time which shape and establish the formation of modern man. Evolution is a term derived from the Latin word ‘unrolling’ and applied to the doctrine that all living organisms have arisen through the modification of other earlier organisms.
It is generally believed that we were separated from apes approximately 6-8 million years ago. Evidence provided by the fossil remains of early hominids from the period 3-4. 5 million years ago were recovered in East Africa in the mid 1970’s. Other biochemical evidence, demonstrates a very close genetic relationship between human beings and the living African apes, particularly the chimpanzee (99% matching genetic makeup). The relationship is apparent at a cellular level, sequences of DNA, and similarities in proteins.
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It is believed that our ancestors and those of the gorilla and chimpanzee had a common line for several million years after they were separated from what is believed to be our earliest ancestor – the orang-utan (Birkett 1982). The earliest known hominid remains dated around 4. 4 million years, and was discovered in Ethiopia in 1992. They belong to a species called Australopithecus ramidus (5-4 million years BCE). In Handar Valley Ethiopia, a slightly more advanced creature was detected. The material discovered was three million years old including ‘Lucy’ a bipedal hominid whose skeleton was found 40% complete.
The remains show a picture of a small, slender but strong hominid, whose pelvis and lower limb bones were no larger than those of apes, the teeth still retained signs of ape ancestry. Lucy had similar teeth to modern Homo sapiens, evidence suggests that she had an omnivorous diet, Other fossils found include hominid footprints found in Laetoli, Tanzania. In this case the hominids had walked over a fall of fine volcanic ash shortly after it had fallen, the rain and the ash hardened like cement. The footprints were then preserved and left untouched until their find.
In 1924 a slightly altered creation of being was discovered, Australopithecus africanus. Africanus had heavy jaws and large canine teeth. The rest of the teeth resembled that of modern people. Australopithecus africanus was slim built, weighed 30 kg and walked upright there are scientists who assume that these parents no longer lived in the forests but on the savannas, made use of tools and hunting practiced in groups. Dating back 3. 0 to 2. 0 million years ago a slightly altered creature came into being, Australopithecus Robustus.
Robustus had a body similar to that of africanus , a larger and more robust skull and teeth. It had relatively small front teeth, but large grinding teeth in a large lower jaw. Most specimens have sagittal crests. Its diet would have been mostly coarse, tough food that needed a lot of chewing. Bones excavated with robustus skeletons indicate that these bones may have been used as digging tools. All early hominids so far are grouped in the genus Australopithecus discovered 4-2. 7 million years BCE. All finds are restricted to Eastern and Southern Africa.
This has made many in this field of work believe that human life originated in Africa and spread outwards. At around this time the dense forestry that covered the land developed more into grasslands with only patchy areas of forest. It is likely that the hominids lived in more open country than the great apes, but still returned to the trees to avoid danger. The increase in the earth’s temperature may have meant long dry seasons, at which time a lot of the vegetation by which it is thought their diet mainly consisted of, would have dried up.
The herbivorous animals living on the plains would have also struggled to find food and the majority would have died out. In the late Pliocene era one line of the Australopithecines began to develop a larger brain, this could be due to increase in protein from the change to a more meaty diet. Fossils of these hominids are sufficiently human-like; they are classed in our own genus, Homo the best known specimens of this line are the Homo habilis stone tools began to appear, giving us the first direct archaeological evidence of behaviour.
Australopithecus boisei is the greatest in size of all the australopithecines. It was the largest of the australopithecines and it had developed larger teeth and jawbones. The Advanced Australopithecus is distinguished from the other australopithecines due to its advanced features such as greater intellect. Many scientists feel that this australopithecine should be regarded as the ‘true man. ‘ They also call Advanced Australopithecus “Homo habilis. ” nevertheless; Homo erectus is now classified as the first true man.
Homo erectus contained a more primitive brain, which had a cranial capacity to half the size of Homo sapiens. In addition, Homo erectus led a social life, could use fire and could communicate. Immediately after this the Neanderthal man was in existence, it had a cranial capacity similar in size to Homo sapiens. The Neanderthal man had further advances in life style. He made simple clothes and constructed tools of advanced design. Stone tools clearly imparted a major advantage to the hominids. By 1. 8 million years ago a variety of homo rapidly achieved stature similar to that of modern human beings.
Brain size increased to t 800 – 1000 cubic centimetres known as Homo erectus, found in Africa, Asia and Europe, gradually moving away from Africa. How human their behaviour was is still debated, but it is clear they had the ability to adapt to the seasonal climate of the temperate zone (Carter 1983). Through the Pliocene period the trend towards larger brains continued (Barrett & Spencer 1997). Homo sapiens appeared about 300 000 years ago. In this period there is no sudden change in stone tools to mark the transition to Homo sapiens.
Roughly 250 000 years ago techniques of manufacture had reached a new sophistication. The Neanderthals are easily recognisable by their combination of long, low skull, large face and robust bodily skeleton. The most plentiful evidence for early specimens of anatomically modern human beings comes from Ice age Europe. Scientists are unsure as to how this displacement took place, as there has been no definitive sign unearthed indicating that any one event had taken place, some postulate that the Homo sapiens may have introduced a devastating disease that wiped out the other groups.
Even before modern Industrial technology, human populations colonized the worlds. The spread outside the ‘old’ world happened within the last 100 000 years and can be linked with the relatively advanced skills and technologies that Homo sapiens possessed. Evolution happens when there is a change in the allele frequency. The Hardy-Weinberg principle states that, in a large population, the frequency remains constant unless some outside force acts to change it therefore forces beyond our control provide us with the driving force for evolution, and is the reason we exist and are who we are today.