The Human Origins Debate - Essay Example

How the Debate Concerning Human Origins Began.... Introduction Creation versus evolution 3 Paleoanthropology..................3-4 Out of Africa model...........4-5 Multiregional model...........5-6 Hybrid theory.................6 Conclusion.........................6-7 Bibliography.......................7-8 Introduction The subject of the origins of humanity and evolution has been a matter of considerable political and religious debate and controversy for both the scientific and the non-scientific community for many years. While most people accept that human evolution is concerned with the study of human origin, defined as the development of humans as a separate species from other primates, many others refuse to recognize the common ancestry we share with a "lower order of animals" (Flank). Creationism is a movement that rejects evolution and the abundant existing scientific evidence that supports it. Creation versus evolution The creation versus evolution controversy, also termed the "origins debate", is the expression used to refer to the ongoing dispute between those that defend the consensus of the scientific community with regards to evolutionary biology, paleonthology, etc. against those that support creationism, a religious-based belief that attributes the creation of Earth, humanity and the universe to a God or deity (Hayward, 1998). The creation versus evolution debate is most prevalent in the conservative regions of the United States, where Creationism is believed to have strengthened after World War I as a consequence of stories that became popular at the time and told of the German aggression being a result of their belief in the concept of "survival of the fittest" introduced by Charles Darwin (Numbers and Coleman, 2007). After this, the situation worsened in many cases when several US states passed laws against the teaching of evolution in public schools and others went a step further by introducing the teaching of creationism instead. It is so that the study of evolution was not included until the late 1960s in textbooks of many US sates. Even during the 1980s, creationism was quite prevalent in certain states (Arkansas and Louisiana), where creationism and evolution obtained equal teaching time in public shools' curricula. This seriously opposes the separation between State and Church recognized in the Constitution, which would avoid interference in each other's issues. The legislation passed for the teaching of creationism seriously contravenes the First Amendment, which states as follows: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..." Consequently, in 1987 the Supreme Court declared this law illegal and an unconstitutional intrusion of religion in public schools. Paleoanthropology Evolution is supported by the study of paleoanthropology. Until the 19th century, the similarity between apes and humans had been sorely discussed and, based purely on morphological similarities, chimpanzees and gorillas were thought to be our closest relatives. In fact, some scientists of the time believed that humans and apes shared a common ancestor and that fossils of this ancestor would eventually be found in Africa. It was not, however, until the discovery of Neanderthal man in 1856 was made and Darwin published On the Origin of Species a few years later, that the concept of evolutionary theory was first introduced. A few years later, paleoanthropology, the discipline that studies ancient populations using fossil evidence in the form of petrified bones and foot prints, as well as the remains of tools and forms of habitation, began. Although there had been a series of minor findings in the 1830s, it was not until 1924 that the first remains of a hominid were discovered in Africa. The fossils were thought to be part of the skeleton of an Australopithecus africanus, a species with a small skull that contained a small but, contrary to those of apes, rounded brain, like that of a human. Additionally, and perhaps more importantly, there was evidence of bipedal locomotion, which confirmed the individual to be a transitional species between ape and human. The australopithecines, species to which the Australopithecus belong, are currently believed to be the immediate ancestors of the species Homo (Latin term for "man"), to which humans belong. Out of Africa model The Out of Africa model was developed by Christopher Stringer and Peter Andrews and is the model currently supported by the majority of the scientific community. They maintain that it was in the African continent more than 200,000 years ago that the modern Homo sapiens evolved. From there, this species migrated into the European and Asian continents approximately 50,000 years ago, where they would replace the native hominid species (Stringer and Andrews, 1988). Recent scientific research into the analysis of mitochondrial DNA (mtDNA) seems to support their claim. Using in excess of 100 different types of mtDNA for the study, it has been concluded that the modern human race descends from one woman from the region of the Great Rift Valley in South-central Africa, a woman now commonly know and referred to as "Mitochondrial Eve" (Cann, Stoneking and Wilson, 1987). A recent study carried out at the University of Cambridge (Cambridge, UK) has also confirmed that "we are solely children of Africa" (Owen, 2007), strengthening the Out of Africa model. In this research, the examination and measurement of approximately 6,000 skulls representing more than 100 ancient human populations was combined with the analysis of genetic variations. A total of 37 measurements from skulls of both sexes and less than 2,000 years old (to ensure accurate measurements) were taken. The lowest amount of variation was observed in the ancient populations that inhabited Australia and South America, the two regions further away from Africa, a result that would be expected if the modern human race evolved exclusively in Africa. In other words, these results confirm that "the more you move away from that center of diversity [], the less diversity you have". Multiregional model The claim of an African origin of modern humans contrasts with the Multiregional model, which maintains that the modern Homo sapiens evolved from a diversity of human populations that inhabited the different regions of the world. A minority of researchers believe that the modern human race is partly the result of the evolution of non-African species that derived from individuals that originated in that continent and migrated more than 1.5 million years ago (Roach, April 3, 2007). Hybrid theory A further group of scientists maintains that there has been interbreeding between the early humans found in Africa and other more archaic species that had earlier left the continent: Neandertals of Europe, humanoids from Australasia, etc. This claim is based on the fact that there are certain genetic and anatomical traits observed in fossils that cannot be explained as a simple migration of modern humans from the African continent. The anthropologist Erik Trinkhaus maintains he has found fossil evidence suggesting that Homo sapiens and Neandertals did interbreed (Roach, January 16, 2007). Conclusion It can be concluded that there is general consensus in the fact that there has not at any point been a wave of early modern humans starting from somewhere else (other than Africa) in the planet since, as a result of this, more genetic variability would have been identified in other areas. Conversely, while some scientist maintain that the human race descends from one African woman whose species reproduced and spread into the remainder of the continents, others believe we are a result of interbreeding between different waves of hominids that migrated from Africa at different points in time. There is strong scientific evidence that could be employed to support any of the aforementioned claims but, whichever one chooses to accept or support, the fact that humans and apes share a common ancestry is beyond question. Creationism should not be part of this debate, since science has provided us, and will continue to do so, with the tools that will help researchers resolve the issue of the origins of humankind. Bibliography -Cann R. L., Stoneking M., Wilson A. C. (1987). Mitochondrial DNA and human evolution. In: Nature, Vol. 325, pp. 31-36 -Flank L. Creationism/ID. A Short Legal History. In: Talk Reason. Available at www.talkreason.org/articles/HistoryID.cfm Date last accessed: February 24, 2008. -Hayward J. L. (1998). The Creation/Evolution Controversy: an Annotated Bibliography. Scarecrow Press/Salem Press. -Numbers R.L. and Coleman W. (2007). Creationism. In: Microsoft Encarta Online Encyclopedia. Available at http://encarta.msn.com/text_761580511___0/Creationism.html Date last accessed: February 24, 2008. -Owen J. (2007). Modern Humans Came Out of Africa, "Definitive" Study Says. In: National Geographic News. Available at http://news.nationalgeographic.com/news/2007/07/070718-african-origin.html. Date last updated: July 18, 2007. Date last accessed: February 24, 2008. -Roach J. (2007). China's Earliest Modern Human Found. In: National Geographic News. Available at http://news.nationalgeographic.com/news/2007/04/070403-china-human.html Date last updated: April 3, 2007. Date last accessed: February 24, 2008. -Roach J. (2007). Neandertals, Modern Humans May Have Interbred, Skull Study Suggests. In: National Geographic News. Available at http://news.nationalgeographic.com/news/2007/01/070116-neanderthals.html Date last updated: January 16, 2007. Date last accessed: February 24, 2008. -Stringer C. and Andrews P. (1988). Genetic and Fossil Evidence for the Origin of Modern Humans. In: Science, Vol. 239, pp. 1263-1268. Read More