Figure 1 - detail: Study dataset, sampling, and estimated metrics on trees. Nine time-calibrated molecular megaphylogenies at species level were sampled through four different schemes: temporal sampling at 5 Myr intervals, taxonomic sampling from family up to order, and random extraction at nodes or internal branches. We estimated shape, branch length distribution and diversification metrics on each resulting tree.
Evolutionary dynamics operating across deep time leave footprints in the shapes of phylogenetic trees. For the last several decades, researchers have used increasingly large and robust phylogenies to study the evolutionary history of individual clades and to investigate the causes of the glaring disparities in diversity among groups. While typically not the focal point of individual clade-level studies, many researchers have remarked on recurrent patterns that have been observed across many different groups and at many different time scales. While previous studies have documented various such regularities in topology and branch length distributions, they have typically focused on a single pattern and used a disparate collection (oftentimes, of quite variable reliability) of trees to assess it. Here we take advantage of modern megaphylogenies and unify previous disparate observations about the shapes embedded in the Tree of Life to create a catalog of the “major features of macroevolution”. By characterizing such a large swath of subtrees in a consistent way, we hope to provide a set of phenomena that process-based macroevolutionary models of diversification ought to seek to explain.