Fish fossils plug hole in evolutionary theory
Previous message: [Marxism] Query concerning Jean van Heijenoort Next message: [Marxism] Dog Wags Tail, Bites Nobody Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] -------------------------------------------------------------------------------- By Julie Steenhuysen CHICAGO (Reuters) - Some odd-looking fish fossils discovered in the bowels of several European museums may help solve a lingering question about evolutionary theory, U.S. researchers said on Wednesday. The 50 million-year-old fossils -- which have one eye near the top of their heads -- help explain how flatfish such as flounder, sole and halibut developed the strange but useful trait of having both eyes on one side. For flatfish, which lie on their sides at the bottom of the sea, this arrangement gives them the use of two watchful eyes. But the trait has posed a problem for evolutionary biologists because no one had found any so-called transitional fossils -- fossils showing intermediate steps in the evolution of this trait. "The important thing about this study is it delivers evidence of those intermediates," said Matt Friedman of The Field Museum and the University of Chicago, whose study appears in the journal Nature. This missing link in the evolution of flatfishes has been seen as a hole in the theory of natural selection. The argument is that intermediate forms of these fish could not exist because there would be no survival benefit from having one eye that was slightly off center, but still on the opposite side of the head. Biologists have theorized that maybe the changes occurred all at once with a large-scale mutation. According to this popular "hopeful monster" theory, flatfishes developed this weird trait, which luckily turned out to be very useful. Friedman's find now suggests that flatfishes followed a more conventional evolutionary plan. "There was no macromutation that all of a sudden gave them both eyes on the same side of the head," he said in a telephone interview. complete article: http://news.yahoo.com/s/nm/20080709/sc_nm/fish_fossils_dc_1 This message has been scanned for malware by SurfControl plc. www.surfcontrol.com _______________________________________________ Marxism-Thaxis mailing list Marxism-Thaxis@lists.econ.utah.edu To change your options or unsubscribe go to: http://lists.econ.utah.edu/mailman/listinfo/marxism-thaxis
