Databases of plant traits and plant genes are approaching the tens of thousands of species in many cases which means we beginning to get a real handle on the evolution of plant traits at a global scale. This is very exciting, but as this is very new the evidence to describe both the pattern and processes at this scale are currently only fragments of the whole picture.
We built a phylogenetic tree for more than 32,000 species of plants and a database on the woodiness of more than 49,000 species. Analyzed together we were able to understand the rates of woody-herbaceous transitions for all land plants and the importance of these transitions for the movement of angiosperms into freezing environments.
A. E. Zanne, D. C. Tank, W. K. Cornwell, and others. 2014.Three keys to the radiation of angiosperms into freezing environments Nature
Building on this resource and together with some very cool models for variation in transition rates among different clades we were able to build the first quantitative model for the precursor to symbiotic N fixing.
Gijsbert D. A. Werner, W.K. Cornwell, J.I. Sprent, J. Kattge & E.Toby Kiers. 2014. A single evolutionary innovation drives the deep evolution of symbiotic N2-fixation in angiosperms. Nature Communications
We were also able to look for the most distinctive clades with respect to functional traits
W. K. Cornwell and others. 2014. Functional distinctiveness of major plant lineages. Journal of Ecology. 102: 345–356
These patterns are, of course, created by ecological processes. But at this phylogenetic scale there are many, many processes at work. We are investigating how well simple models match to the data and when and where the models–even the *best available* model–fails.
M. Pennell, R. G. FitzJohn, W. K. Cornwell, L. J. Harmon. Model adequacy and the macroevolution of angiosperm functional traits. bioRxiv preprint
We have also examined patterns of sampling bias and how they effect simple global summary statistics like how many of the world’s species are woody.
R.G. FitzJohn, M.W. Pennell, A. E. Zanne, P.F. Stevens, D.C. Tank, W.K. Cornwell. How much of the world is woody? Journal of Ecology Early View