**Date/Time**

Date(s) - 17/01/2023*3:30 pm - 5:00 pm*

**Speaker: **Ben Bolker, McMaster University

**Title:** Estimating state-dependent evolutionary rates: parental care, sperm competition, and fish accessory glands

**Abstract: **Biologists often want to understand why certain traits of organisms evolved. One way of translating this question into a statistical context is to set up a continuous-time, discrete-state Markov process along the branches of a phylogenetic tree and estimate how the evolutionary rates (log-hazards of changes in particular states) vary depending on the current values of other traits. Using an example from fish biology I will explain how to estimate the log-likelihood of a set of tip states given a transition matrix; based on this computation we can use standard MCMC techniques to estimate linear contrasts that describe the effects of one biological trait on the evolutionary rate of another trait. I hope to rant briefly about statistical philosophy (scientists and many other people have been brainwashed into thinking that they should make discrete categorical predictions and test discrete hypotheses: quantifying rates and probabilities is usually much more useful).

**Date/Time: **Tuesday January 17, 2023, 3:30 – 5:00

**Location:** MDCL 1115