ORIGIN OF MODERN HUMANS.   Term Paper ID:17210 Click to get this paper

Essay Subject: History & development of Homo Sapiens. Neanderthals, physical changes, Noah's Ark theory, DNA, gene flow.... More...

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Paper Abstract: History & development of Homo Sapiens. Neanderthals, physical changes, Noah's Ark theory, DNA, gene flow. Paper Introduction: THE ORIGIN OF MODERN MAN Four hundred thousand to two hundred thousand years ago, Homo erectus disappeared from the face of the earth and in his place was left archaic Homo sapiens, also known as Homo sapien neandertalensis or Neandertal man. Neandertal man had spread throughout Europe, the Near East, and Asia before one hundred thousand years ago. Then, quite suddenly, anatomically modern humans appeared throughout the Old World, replacing Neandertal man completely by about thirty-five thousand years ago (Fagan, 1989). The question that arises is whether Neandertal man evolved to become modern man, or if modern humans migrated into the areas that were inhabited by the Neandertals and eventually replaced Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. The first is the Neandertal phasehypothesis, which says that Homo erectus populations throughout the worldevolved independently, first to archaic Homo sapiens, then to fully modernhumans. There is now only one human form, indicatingthat modern humans originated in a single region. First, modern man could not have evolved in more than one place;as humans we are far too similar morphologically to have evolved separately(Fagan, 1989; Trinkaus, 1983). THE ORIGIN OF MODERN MAN Four hundred thousand to two hundred thousand years ago, Homo erectusdisappeared from the face of the earth and in his place was left archaicHomo sapiens, also known as Homo sapien neandertalensis or Neandertal man.Neandertal man had spread throughout Europe, the Near East, and Asia beforeone hundred thousand years ago. According to Cann, " . This seems like an unlikely possibility. BIBLIOGRAPHYBinford, Sally R. If Neandertal would have evolved intomodern man, it seems likely there would have been an intermediate step inthe evolution, one which we do not find. These Neandertals were robust, with massive brow ridges,enlarged brain size, and high foreheads. Not everyone is convinced that this increased gene flow came fromAfrica. Or, perhaps they interbred with new arrivalsuntil the two groups were no longer distinguishable. Otherwise, it would be very difficult to imagine how the Lena Valley could have been occupied so early. The Shanidar Neandertals. There are other theories that state that modern man evolved inAsia: In recent years, we have become accustomed to the idea that only one continent, Africa, may be considered as the homeland of mankind. Until then, this theorydoes not seem valid. These early inhabitants must have had clothing and control over fireto have been able to withstand such a frigid climate. People have beenevolving in Africa longer than anywhere else. They lived in caves androck shelters during most of the year and had control over fire. If the latter is thecase, then Neandertal was not the only ancestor, but one ancestor of modernhuman populations. An increasedgene flow is necessary to explain how Neandertals and anatomically modernhumans remained genetically separate within a restricted geographical rangefor thousands of years (Trinkaus, 1989). In the search for the origin of the strands of DNA, also the originof modern man constructed an "evolutionary tree" of one hundred forty-sevensamples of mitochondrial DNA from people around the world, making itpossible to trace the line of descent to one woman - "Eve." All evidencepoints to this woman being African. This makes Africa appear to be a likely place of origin. Similarly, according to Cann, "If modern humans had originatedsimultaneously in two such widely separated regions, adapting to two suchdifferent environments, we could expect that two distinct human forms wouldhave evolved" (1987, 33). Maybe they werevictimized by the newcomers. . This is important since it places Siberia within the zone of theevolution of Homo sapiens. When DNA reproduces itself, some of it is alteredaccidentally. However convincing this argument may ormay not sound, Asian paleontologists have yet to produce any solid evidenceof the evolution of Homo sapien sapiens in Asia. Perhaps as excavationscontinue, more data will be available to process. 4 (1987).Thomas, David Hurst. People of the Earth. This makes evolution fromNeandertal man unlikely. This new site, Diring-Ur'akh, reminds us of the earlier, and now forgotten, concept of man's origins in the interior of Asia. Archaeology. Trinkaus believes that change came from within the neandertalpopulation itself (1983), and describes the fossil record as a "mosaic ofevolutionary change and stability" (472). This suggests thatthey were very advanced for their apparent age. A cave site inthe same vicinity has yielded bones and a tooth which are from archaic Homosapiens. One question still remains: what happened to archaic Homo sapiens?If Homo sapien sapiens migrated into their territories, as the evidenceseems to point to, what caused the archaic peoples to vanish? These alterations must have been produced by a shift in selective pressures resulting in a marked shift in gene frequencies, and probably involving introduction of new genetic material into populations in the Near East. Evolutionary change begins with these mutations in geneticmolecules. Neandertals were skilled hunters and gatherers who made and usedartifacts such as spears, scrapers, and hand axes. Thisdate shows that modern people from around the world have a common ancestorof about two hundred thousand years ago (Cann, 1987). Modern man and the archaic Neandertal man may havecoexisted in Europe (Fagan, 1983). There is also somediscrepancy between this evidence and the fossil evidence, with adifference of about one hundred thousand years. Thismeans archaic modern humans coexisted, with no apparent intermediary (?) tobridge the evolutionary gap between the two. The specific physical characteristics of Neandertal differedthroughout Europe, Asia and the Near East, and it does not seem likely thatthe evolutionary process would diminish these differences. (Larichev, Khol'ushkin, and Laricheva, 1987, 421)The Lena Valley in Siberia was occupied as early as 1.5 to 2 million yearsago. Trinkaus (1985, 453) concludes that this evolution is notlikely and presents an alternative theory. "Stone Tools and Human Behavior," Scientific American, 1969.Cann, Rebecca. However, Fagan does agreeon a different level: "Everything points not to anatomical continuity inEurope and the Near East but to replacement of Primeval populations by Homosapiens" (1989, 15 ). The second hypothesis uses the Noah'sark model. An archeologist named Gunter Brauwercan identify at least three "grades" of Homo sapiens in sub-Saharan Africa. They both agree that a migration from a specificregion throughout the entire Old World occurred. It is also important tonote that the tool types found in the area have been previously found onlyin Homo erectus sites in Africa. Then, quite suddenly, anatomically modernhumans appeared throughout the Old World, replacing Neandertal mancompletely by about thirty-five thousand years ago (Fagan, 1989). Although excavations move slowly in that partof the world, these discoveries have led paleontologists to believe thatsimilar sites will be found in other regions of northern Asia as well(Larichev, Khol'ushkin, and Laricheva, 1987), but have yet to bedocumented. itwould be difficult to explain how they (Neandertals) kept essentially thesame form for sixty thousand years, then, overnight, evolved into a newsubspecies forty thousand years ago, when modern humans first appeared inEurope" (1987, 33). "In Search of Eve," The Sciences. However, if modern populations had already replacedNeandertals in the Near East, they may have just continued the migrationwest into Europe and coexisted with the already present archaic populationsuntil they eventually replaced them. From there theymigrated into Europe and Asia (1989). It is hard tobelieve that under such varied conditions man would have evolved in exactlythe same way. He believes that very early anatomically modern Homo sapiens were widelydistributed in eastern and southern Africa as long as one hundred fifteenthousand years ago. Fagan believes that Homo sapiensevolved from archaic Homo sapiens in tropical Africa and then migratednorth into the Near East by forty-five thousand years ago. These harsh conditionscould have been enough to force the evolution of man (Larichev,Khol'ushkin, and Laricheva, 1987). Last, by tracing mitochondrial DNA, a new processthat is still in its beginning stages, the length of time from whence onehuman and another have been genetically separated can be determined. Perhaps theywere simply out-populated and eventually died out. The above description isvery general. New York: Holt, Rinehart, and Winston, 1979.Trinkaus, Erik. Perhaps future excavations will give us the answers,but until then we can only speculate. Their height was usually aboutfive feet tall and their bodies very muscular. Theburial of their dead leads Fagan (1989) to believe that they practiced somekind of religion. It states that Homo sapiens evolved in one place then spreadacross the Old World. New York: Academic Press, 1983.----------------------- 1 Because mitochondrialDNA undergoes significant change every few thousand years, it is a goodgauge for short term evolution. By analyzing the DNA molecules of twoanimals and measuring the differences in the sequence of their components,biologists can gauge how long it has been since the two animals divergedfrom a common ancestor. So, these biologistsbelieve that while Neandertals may have evolved from an ancestor common toours, we are not descended from them, but merely successful rivals. Scientists believe the appearance of this new genetic material fromnon-Neandertal human groups is linked to the relatively uniform morphologyof anatomically modern humans across Europe and the Near East. I, No. This shows that these peoples wereevolving in much the same was the peoples of Africa were. There are Africans who can trace theirancestry to the base of the tree without running into any non-Africans.There are not any other groups of people who can do the same. The question that arises is whether Neandertal man evolved to becomemodern man, or if modern humans migrated into the areas that were inhabitedby the Neandertals and eventually replaced them. While this information may seemindisputable, Fagan (1989) stresses that this methodology is still in itsinfancy and its results are highly provisional. The evolution which produced such anatomical change would require alengthy period of time; but this time frame does not appear to exist inEurope. Second, the time that Neandertal would havehad to evolve into fully modern man is too brief, only about five thousandyears (Trinkaus, 1983). An African-only branch of this evolutionary tree contains the most diverse types ofmitochondrial DNA because it is the oldest branch. Thus, according to this hypothesis, moderngeographic populations have shallow roots and were derived from a singlesource of relatively recent times. Greatervariation in physical form would have been expected from separateevolutions or an absence of an elevated level of gene flow (Trinkaus,1983). The degree to which the molecules differ is directly correlatedto the evolutionary distance separating them. The evolved populations would have advantages over the archaicpopulation, just because there would be no other reason to evolve otherthan the adaptive advantages; for the archaic population to still be aroundwould not make sense. The oldest anatomically modern humans inEurope date to about thirty-two thousand years ago which provides thetransition from Neandertal to modern man for less than five thousand years(Trinkaus, 1983). "Lower and Middle Paleolithic of Northern Asia: Achievements, Problems, and Perspectives," Journal of World Prehistory, Vol. Mitochondrial DNA is easierto analyze than nuclear DNA and is only inherited from the mother. Evidence supports the Noah's ark model, that modern man evolved in asingle location and then migrated across the Old World for four basicreasons. Eve lived approximately twohundred thousand years ago (Cann, 1987). September/ October, 1987.Fagan, Brian M. The final bit of evidence that supports the Noah's ark theory is theanalysis of mitochondrial DNA. This hypothesis supports multiple origins of modern man, thus,stating that modern geographic populations have been separated from oneanother for up to one million years. According to Fagan (1989)there are two basic hypotheses. Despite the limited time frame their coexistence indicates thatmodern man evolved elsewhere. and Lewis R. This was well before they existed in Europe (Fagan,1989). So itis immune to change by sexual recombination of genes from each parent;mutation is the only kind of change than can occur. If indeed Neandertals had evolved into fullymodern humans, it would not make sense for them to coexist with oneanother. Glenview, IL: Scott Foresman and Company, 1989.Larichev, Vitaliy, Uriy Khol-ushkin, and Inna Laricheva. . The altera- tions appear to be too marked and anatomically pervasive to have been produced merely by environmentally induced changes during develop- ment. Asia underwent profound changes in paleoclimatic conditions, with aconstant reduction and expansion of inhabitable land area, which would haveforced people to adapt to arctic desert conditions. Despitethe controversy, it seems to be the only region where adequate levels ofevolution occur, in the proper amount of time, without coexisting archaicand modern populations. The gap in the morphology of skeletal remains betweenmodern man and the coexistent archaic man indicates to Trinkaus and othersthat the evolution was not local. Still, not everyone is in agreement that Africa is the origin ofmodern man. Neandertal-like individuals have been found that date to as lateas thirty-six thousand to thirty-one thousand years ago and anatomicallymodern humans were already in Europe at this time (Fagan, 1989). Binford. If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.

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