RainDog
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Wed May-19-10 08:33 AM
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First large-scale test confirms Darwin's theory of common ancestry |
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Edited on Wed May-19-10 08:36 AM by RainDog
http://www.physorg.com/news192882557.htmlThe results of the study confirm that Darwin had it right all along. In his 1859 book, On the Origin of Species, the British naturalist proposed that, "all the organic beings which have ever lived on this earth have descended from some one primordial form." Over the last century and a half, qualitative evidence for this theory has steadily grown, in the numerous, surprising transitional forms found in the fossil record, for example, and in the identification of sweeping fundamental biological similarities at the molecular level.
Still, rumblings among some evolutionary biologists have recently emerged questioning whether the evolutionary relationships among living organisms are best described by a single "family tree" or rather by multiple, interconnected trees—a "web of life." Recent molecular evidence indicates that primordial life may have undergone rampant horizontal gene transfer, which occurs frequently today when single-celled organisms swap genes using mechanisms other than usual organismal reproduction. In that case, some scientists argue, early evolutionary relationships were web-like, making it possible that life sprang up independently from many ancestors.
According to biochemist Douglas Theobald, it doesn't really matter. "Let's say life originated independently multiple times, which UCA allows is possible," said Theobald. "If so, the theory holds that a bottleneck occurred in evolution, with descendants of only one of the independent origins surviving until the present. Alternatively, separate populations could have merged, by exchanging enough genes over time to become a single species that eventually was ancestral to us all. Either way, all of life would still be genetically related....creationism just keeps going down like a five dollah crack ho.
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