Challenge problem 5: Fitting models of discrete character evolution

Using the same data sets as in exercise 12, fit a directional ordered model for hindfoot toe loss (i.e., 5→4→3→2→1→0). How does this model compare to the previous three models?

The data are from Brandley et al. (2008) and are as follows:

1. brandley_table.csv
2. squamate.tre

Written by Liam J. Revell. Last updated 6 December 2016.