Professor Dan Rabosky has been awarded a $600,000 grant from the National Science Foundation for his project, “A macroevolutionary framework to study the assembly of continental biotas.”  

“One of the most striking large-scale patterns in biology is the disparity in both species richness and phenotypic diversity across the Tree of Life,” wrote Rabosky in the project summary. “Some groups of organisms are fabulously diverse, yet many other groups are equally noteworthy for what they lack in diversity. Perhaps nowhere is this pattern more evident than when evolutionary radiations of animals or plants within the same geographic region result in dramatic differences in species richness or morphological diversity. This project will address the causes of this variation by developing new methods for studying evolutionary dynamics and applying them to multiple radiations of Australian squamate reptiles (lizards and snakes). By analyzing both high- and low-diversity groups that have diversified in a common ecological and biogeographic theater, this research will provide a synthetic perspective on the general causes of evolutionary radiations.

“The research will use phylogenetic, ecological, and morphological data from Australian lizards and snakes to address three major questions in the biology of evolutionary radiations. (1) What are the dynamics of species and phenotype diversification through time? (2) Are rates of species diversification coupled to rates of phenotypic evolution? (3) What is the macroevolutionary signal of interactions between clades?” (A clade is a group consisting of an ancestor and all its descendants, a single branch on the tree of life.)

Rabosky’s research will result in a continental-scale perspective on evolutionary radiations that have occurred in the same geographic setting. “Such clades represent an evolutionary ‘common garden’ experiment that may help us to understand the role of historical contingency, key innovations, and environmental change in shaping long-term evolutionary trends. This work will greatly enhance our understanding of the factors that influence clade dynamics through time and will provide an important perspective on the links between macroevolution and the assembly of regional communities. The theory and methods developed through the project will be transformative for phylogenetic biology by equipping researchers with the tools to discover and characterize the elusive mixtures of processes that have shaped the distribution of species and phenotypes across the Tree of Life.

“The project will result in statistical methods and computer software that will enable researchers to study complex, compound, and dynamic processes of diversification and trait evolution on phylogenetic trees. The software will be optimized to analyze massive datasets, thus complementing existing NSF initiatives to reconstruct, visualize, and access the entire Tree of Life. The empirical component of the proposed research will provide the most comprehensive study to date of the evolutionary and ecological processes that influence the assembly of continental biotas, with implications for community ecologists and evolutionary biologists alike.”