Median age of root of the end-experiment phylogenetic trees, and the median distances (in updates) from the root to the first and second next oldest nodes in the tree, for replicate populations in which the pre-extinction root was retained.

Differences between treatments were tested with a Kruskal-Wallis test, followed by a Tukey-corrected multiple comparison test. Letters in “Multiple comparison grouping” indicates treatments that are NOT significantly different after correction for multiple comparisons.