http://www.cnn.com/2010/TECH/science/04/08/hominid.discovery.skeleton/index.html?iref=allsearch
http://www.scientificamerican.com/article.cfm?id=south-african-hominin-fossil
These are articles from CNN and the Scientific American about partial skeletons of an adult female and a male juvenile. In Coyne's
chapter, "What About Us,"specifically in pages 194-210, our Fossil Ancestors are discussed. Coyne goes into detail about two
theories, not debating whether or not evolution occurred, but how. The first theory is the "multiregional" theory (206) which
says that H. erectus evolved into H. sapiens independently in several areas. The second theory is the "out of Africa" theory,
which is supported by genetic and fossil evidence. The "out of Africa" theory says that H. sapiens originated in Africa and
spread. Going back to the articles, just this past week 2-million-old skeletons were discovered in South Africa. Using these
articles, as well as the book and outside sources, discuss the importance of these findings on Evolutionary Theory, and discuss
how this new discovery affects both the "multiregional" and "out of Africa" theories Coyne mentions.
Sorry about how some words split. I tried to fix it, but the margins kept showing up weird when I went to go edit it!
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ReplyDeleteThe multiregional theory is negatively affected by this discovery because the discovery does raise the question as to why we have yet to discover Australopithecus sediba, or other transitional species similar to the Australopithecus sediba in other regions of the Earth. It could be, however, that scientists just have yet to find those transitional species.
ReplyDeleteThe multiregional theory in itself, however, is doubtful because natural selection could not have possibly occurred exactly the same way all around Asia, Europe, and Africa, no matter how similar the conditions. Especially since the multiregional theory believes that the separate hominid populations were separate for hundreds of thousands of years, “the more genetic differences… (would) have accumulated” (Coyne 206) because the chances of the exact same random genetic mutations occurring in every single hominid population are close to nil. The multiregional theory is a call off of convergent evolution it seems. Convergent evolution is where different species in different countries or regions develop similar characteristics to others in similar environments somewhere else in the world (Coyne 94). This is what the multiregional theory claims; that the hominids in different regions, due to natural selection acting the same way, all developed similar characteristics. This may be true. However, we have yet to find two organisms that have been subjected to convergent evolution that are able to successfully mate, as humans are able to. This decreases the likelihood of the multiregional theory.
The out of Africa theory is supported by the discovery of the Australopithecus sediba because since we have yet to discover other hominid species similar to the Australopithecus sediba outside of Africa, it looks as if the Australopithecus sediba only existed in Africa, where they were eventually wiped out by the Homo sapiens, which would account for the fact that we have yet to discover other similar hominid species outside of Africa.
However, couldn’t it just be that the Australopithecus sediba gave rise to the Homo sapien? Instead of being a competitive species versus the H. sapiens, the Australopithecus sediba could just have been a link in the evolutionary chain of the evolution of H. sapiens. Especially since the Australopithecus sediba is 2 million years old (CNN). In which case, the discovery of the Australopithecus sediba doesn’t really help either theory, because hominids had to evolve into Homo sapiens either way; the Australopithecus sediba is just another transitional species. The multiregional and the ‘out of Africa’ theories just debate WHERE the evolution into H. sapiens occurred. The discovery therefore just supports the theory of evolution in general, which happens to be one of our biological themes. The very epitome of this topic/prompt is evolution, which is the development and change of an organism through time. The discovery of another transitional species that could have been ancestor to modern day Homo sapiens further solidifies the theory of evolution, because the new discovery serves as another stepping stone in the view of how hominids evolved over time.
http://www.cnn.com/2010/TECH/science/04/08/hominid.discovery.skeleton/index.html?iref=allsearch