Research in Bruce Lieberman's Lab
Research on the nature and timing of the Cambrian radiation
Studies of evolutionary patterns in trilobites
I have used phylogenetic biogeographic approaches to determine the relationship between earth history change and evolution and also to reconstruct the sequence of Paleozoic tectonic events. One of the time intervals my research has focused on is the Cambrian radiation: that key episode in the history of life when diverse, abundant animal remains appear in the fossil record. I have conducted phylogenetic analyses of the diverse olenellid trilobites and used these to study evolutionary and biogeographic patterns during the radiation.
Phylogenetic and biogeographic patterns suggest that the radiation of trilobites may have been underway in the late Neoproterozoic before the group becomes manifest in the fossil record; these patterns also suggest that the breakup of a supercontinent at the end of the Neoproterozoic had an important effect on the topology of the Cambrian radiation. I've also used probabilistic models to study how fast the rates of evolution were during this interval and the results suggest that rates of evolution were high at the time but not so high that new rules of evolution need to be invoked to explain the Cambrian radiation.
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This research has been supported by the National Science Foundation and the National Geographic Society and has involved fieldwork in the Mackenzie Mountains, Northwest Territories, Canada in collaboration with Mike Pope at Washington State University.
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Studies of Burgess Shale type fossils
| With support from the National Science Foundation we have been studying evolutionary and biogeographic patterns in a Middle Cambrian soft-bodied fauna from Utah. This work is being conducted with my post-doc, Jon Hendricks, and involves collaboration with Derek Briggs, Bob Gaines, and Mary Droser. We have described new taxa from these localities in work that is in press and have also conducted phylogenetic analyses on a series of new arachnomorph taxa that have been recovered from these localities; in addition we are pursuing phylogenetic biogeographic analyses and also biogeographic analyses using Geographic Information Systems (GIS), the latter in conjunction with Alycia Stigall at Ohio University. This work has also been made possible through the generous contributions of specimens by the Gunther family, and Sue Halgedahl and Richard Jarrard, along with the insight and assistance of Richard Robison.
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Research in Paleobiogeography
I am very much interested in paleobiogeographic studies and this has formed an important component of my research. This not only includes my research described above under the heading of the Cambrian radiation but various other theoretical and practical applications. Much of this research has involved phylogenetic approaches. |
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This research has also included applying Geographic Information Systems (GIS) to study biogeographic patterns in deep time using the fossil record. This work was done in conjunction with my former student Alycia Stigall, who is now an assistant professor at Ohio University.
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Research in Astrobiology
Investigating Large Scale Patterns in the History of Life
As part of my research interests in macroevolution and biogeography, one of the topics I have considered is the evidence that at the large scale physical factors play a fundamental role in influencing macroevolution. This has included investigating the evidence that there is a fundamental connection between carbon dioxide levels and rates of evolution and extinction; this work was conducted in collaboration with Bob Goldstein and my former student, Jim Cornette; we found strong evidence that carbon dioxide levels and rates of macroevolution are significantly coupled. In addition, in work led by Jim Cornette, I investigated the extent to which the history of Phanerozoic diversity can be modeled as a random walk; we found strong evidence that except for the last 75 million years life largely follows a trajectory indistinguishable from a random walk. This does not mean that the history of diversity over the last 520 million years is random, and instead it may be that diversity is largely tracking environmental variables that themselves are following a random walk pattern. Most recently, and associated with my work in the area of astrobiology described above, I have been collaborating with Adrian Melott to consider the evidence that there are large scale cycles in biodiversity, possibly associated with astrophysical phenomena. |
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Investigating Phylogenetic Patterns in Cheirurid Trilobites
We have just been funded by the National Science Foundation, through their RevSys program in Systematic Biology, to investigate phylogenetic patterns in the diverse cheirurid trilobites. This work is in collaboration with Jonathan Adrain at the University of Iowa. |
Former Students
Current Students
Francine Abe, who is studying the nature of taxic radiations preserved in the fossil record, fabe@ku.edu
Curtis Congreve, who is studying phylogenetic patterns in cheirurid trilobites and also the nature of the end Ordovician mass extinction, oldjack327@yahoo.com
Corinne Myers (new student for 2007)
Ian Wesley Gapp (new student for 2007)
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Current Post-Docs
| Jonathan Hendricks, Ph.D. Cornell University, investigating phylogenetic and biogeographic patterns in Burgess Shale type fossil arthropods, jrhendri@ku.edu
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Former Post-Docs
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