Modeling patterns of adaptive radiation
Katelynn Wilton
Issue date: 11/23/09 Section: News
On Friday, November 20, all the way from the second floor of the Science Center, Clarkson hosted Dr. James Schulte for the final mathematical-biological seminar of the semester. Dr. Schulte introduced attendees to the "Modeling patterns of adaptive radiation," a project that he worked on with Luke Harmon.
Dr. Schulte started his presentation by introducing the audience to some species that have undergone adaptive radiation, including the Hawaiian Silverswords, the African Driftlake Cichlids, the Knowle Lizards and of course Darwin's finches. This left the audience wondering what exactly adaptive radiation was, until Dr. Schulte began to delve into the various definitions that have evolved with different research. First, he described how Hanry Fairfield Osborn, the artistocratic director of the American Museum of Natural History studied many of the vertebrate mammals and dinosaurs that came into his collection. He used them to trace lines of evolution and noticed a general diversification of species occurring rapidly in time.
George Gaylord Simpson then continued the work and noted that when species radiated, they appeared to explode from occupying a single environmental niche to occupying several niches. He postulated that this was due to key innovations and adaptations that allow species to adjust to more than one niche. One such example would be when birds developed wings and more importantly flight. They could therefore begin to fill niches that had been unpopulated before.
Dr. Schulte then explained that several definitions had been proposed for adaptive radiation, including the definition proposed by the group that he had worked with: "Strong negative between subclade morphological overlap and rapid early lineage diversification." In other words, closely related groups known in evolutionary studies as subclades become very different from each other and their lineages, or trends of evolution became rapidly different at some point in time.
Dr. Schulte started his presentation by introducing the audience to some species that have undergone adaptive radiation, including the Hawaiian Silverswords, the African Driftlake Cichlids, the Knowle Lizards and of course Darwin's finches. This left the audience wondering what exactly adaptive radiation was, until Dr. Schulte began to delve into the various definitions that have evolved with different research. First, he described how Hanry Fairfield Osborn, the artistocratic director of the American Museum of Natural History studied many of the vertebrate mammals and dinosaurs that came into his collection. He used them to trace lines of evolution and noticed a general diversification of species occurring rapidly in time.
George Gaylord Simpson then continued the work and noted that when species radiated, they appeared to explode from occupying a single environmental niche to occupying several niches. He postulated that this was due to key innovations and adaptations that allow species to adjust to more than one niche. One such example would be when birds developed wings and more importantly flight. They could therefore begin to fill niches that had been unpopulated before.
Dr. Schulte then explained that several definitions had been proposed for adaptive radiation, including the definition proposed by the group that he had worked with: "Strong negative between subclade morphological overlap and rapid early lineage diversification." In other words, closely related groups known in evolutionary studies as subclades become very different from each other and their lineages, or trends of evolution became rapidly different at some point in time.
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