Macroevolution
Overview
Curator Bruce S. Lieberman's entire career has been dedicated to the study of the patterns and processes of macroevolution using the fossil record. He was taught by the three leading figures of macroevolution: his undergraduate advisor was Stephen Jay Gould at Harvard College, his graduate advisor was Niles Eldredge at Columbia University and the American Museum of Natural History, and his first post-doctoral advisor was Elisabeth Vrba at Yale University.
Bruce's research focuses on the role climate change and abiotic factors play in driving evolution and extinction, the nature of evolutionary radiations, how and why rates of evolution vary through time, the dynamics of mass extinctions, mechanisms of evolutionary stasis and punctuated equilibria (Scholarpedia.org), phylogenetics, and biogeography.
Work in his lab has also pioneered the application of Geographic Information Systems (GIS) and Ecological Niche Modeling (ENM) to the study of the fossil record, emphasizing biogeographic and evolutionary patterns in deep time. Various projects in this area include work with former students and post-docs Luke Strotz, Erin Saupe, Corinne Myers, Alycia Stigall, and Jonathan Hendricks documenting:
- The important role that physiology plays in mediating macroevolution.
Research: Metabolic rates, climate and macroevolution: a case study using Neogene molluscs, Proceedings of the Royal Society, 2018.
- How species niches are conserved over millions of years.
Research: Macroevolutionary consequences of profound climate change on niche evolution in marine molluscs over the past three million years, Proceedings of the Royal Society, 2014.
- The relative roles that niche breadth and geographic range play in determining long term species survival.
Research: Niche breadth and geographic range size as determinants of species survival on geological time scales, Global Ecology and Biogeography, 2015.
- The dire threats our marine biota faces in the near future due to changing climate.
Research: Climate change and marine molluscs of the western North Atlantic: future prospects and perils, Journal of Biogeography, 2014.
In addition, this work has demonstrated:
- The overwhelming role that abiotic factors, as opposed to competition, play in determining long term species survival.
Research: Sharks that pass in the night: using Geographical Information Systems to investigate competition in the Cretaceous Western Interior Seaway, Proceedings of the Royal Society, 2011.
- The role that invasive species played in mediating the Late Devonian biodiversity crisis.
Research: Using GIS to unlock the interactions between biogeography, environment, and evolution in Middle and Late Devonian brachiopods and bivalves, Science Direct, 2004.
- The paleobiogeography of the distinctive creatures found in the Burgess Shale.
Research: Using GIS to study palaeobiogeographic and macroevolutionary patterns in soft-bodied Cambrian arthropods, Science Direct, 2008.
Large-scale Patterns in the History of Life
As part of Lieberman's research interests in macroevolution and biogeography, one of the topics he has 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 significant coupling between carbon dioxide levels and rates of macroevolution. In addition, Bruce along with former student and emeritus University Professor of Mathematics at Iowa State University James Cornette investigated the extent to which the history of Phanerozoic diversity can be modeled as a random walk and found strong evidence that except for the last 75 million years marine animal diversity and origination 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. More recently, and associated with his work in the area of astrobiology described above, he has been collaborating with Adrian Melott to help demonstrate that there are large scale cycles in the fossil record of biodiversity, origination, and extinction operating on the order of tens of millions of years. Lieberman and Melott have also identified how volatility is a key trait uniting things as diverse as fossil species, stock prices, and the birth and death of stars in our universe. Each of these findings indicates that although the history of life is governed by contingency, this contingent system also shows predictable patterns.