Francesco Santini

#evol2018 HARMON: tailed-frogs can jump, but can't land. Showing some amazing videos

#evol2018 HARMON: tailed frogs belong to a tiny clade of frogs, sister to another clade that includes all other frogs. This pattern is very common across the tree of life, groups referred to as "depauperons", sp.. poor clades sister to more diverse related lineages

#evol2018 HARMON: why is the tree of life so imbalanced? Over the last few years a number of methods have been developed to identify characters that we can associate with differences in speciation and extinction, and hopefully help us understand why the tree of life is this way

#evol2018 HARMON: there are now too many explanation for why diversification rates vary across clades. Not all of these are probably correct, difficult to understand why which ones apply at times

#evol2018 HARMON: use of shape of trees to look at speciation rates and understand what drives diversification has been done since 1990s, more recent attempt to integrate this with fossil record

#evol2018 HARMON: with number of collaborators assembled huge dataset of speciatin rates, just submitted paper to arxiv, used Bamm to analyze rates across dozens of phylogenies and used fossil record to look at time series occurrence data

#evol2018 HARMON: speciation rates across clades vary by more than 2 orders of magnitude. Stunning diversity across tree of life. Estimates for speciation and extinction rate plotted against clade age in dated trees match patterns seen in fossil record.

#evol2018 HARMON: speciation and extinction rate estimates are strongly scale dependent. This pattern has implications for interpretation of speciation rate estimates

#evol2018 Harmon: a number of studies show high speciation rates in young clades. How real is this pattern and how much is due to potential statistical bias?

#evol2018 Harmon: multiple potential statistical biases, but believes statistical effects are part of the story, but not whole story

#evol2018 Harmon: there are biological explanations for pattern observed, including ecological limits, accelerating evolution, macroevolutionary pulses, and hierarchical models of evolution

#evol2018 Harmon: using Bamm can address idea of ecological limits or macroevolutionary pulses directly

#evol2018 Harmon: based on results neither ecological limits nor accelerating evolution seem to explain the pattern

#evol2018 Harmon: fossil record & stratigraphy shows often pattern of not much happening for a long time, followed by pulse of rare and intense change. A number of macroevolutionary studies have recovered this pattern

#evol2018 Harmon: speciation may be ephemeral, many species may form but not persist for long. "successful" speciation requires the confluence of many factors

#evol2018 Harmon: hierarchical ephemeral models may help advance understanding of speciation and extinction across the tree of life

#evol2018 Harmon: has free book on comparative methods just published available from personal github site