Genetic Replacement Model

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In the study of evolution, DNA is arguably the most important aspect as it shows the differences between one species and another. Almost everyone has heard the phrase “we share 99% of our DNA with chimpanzees,” and in reality, research of the human genome shows that the gene difference between humans and chimps is around 2%. Scientists have long studied the similarities and differences in the chromosomes of humans and living primates in order to determine how genetically related the two species are. Genetic information is valuable as it sheds light on hominid evolution and provides data on the approximate time when two species diverged from a single common ancestor and began evolving on their own. Therefore, similarities in the genetic code …show more content…
Upon initial discovery and classification, Homo Neanderthalensis were believed to be a transitional species between Homo erectus and Homo sapiens. This idea is proposed in the replacement model, which suggests that the Neanderthals became extinct and was replaced by Homo sapiens. A better model proposed to attempt to explain human evolution is the hybridization and assimilation models (Bonvillain 2013: 272). It proposes that as a result of interbreeding, anatomically modern humans hybridized with archaic hominid populations and eventually replaced them. This model is supported by fossil evidence from Europe, East Asia and the Near East which indicate that different hominid species did indeed overlap in time and space. This fact provides one of the prerequisites for the theory of interbreeding. If the two species in question did indeed exist at the same time and place, it becomes possible for interbreeding to have occurred. Fossil evidence has been found that date between 130 000 and 30 000 years ago, in distinct geographical regions where modern humans would have existed (Bonvillain 2013: 273). Therefore, it can be concluded that they coexisted with anatomically modern humans in in the relatively recent past. Furthermore, recent stone tool findings suggest that Neanderthals trekked from Europe to East Asia 75 000 years ago (Bower 2012: 26), giving them …show more content…
Despite the vast amounts of information we have already obtained about Homo sapiens, we are still struggling to fill gaps about transitional species and our evolutionary ancestors. The articles by Hofreiter and Bower attempt to provide information to explain the role of Homo sapiens neanderthalensis in human evolution, via the examination of fossil and genetic evidence. Since the initial discovery and classification of Neanderthals as a species, scientists have tried to use evolutionary models to explain their relevance. In popular culture, the image of the Neanderthal has become the prototype for the stereotypical “cave man”, we view them as “second-rate” hominids but in fact, they are a distinct species that happened to end in extinction. Now, we are closer to figuring out the links between Neanderthals and modern humans; they are not a transitional species, they are not brutish, apelike creatures, they are, in fact, a contribution to our evolutionary history. Neanderthals contributed parts of their genome to present day populations of humans, and while their contributions might seem insignificant, humans would be very different beings had Neanderthals not