Undersampling affects spectral density profiles. The spectral densities of 3 (out of 100) trees (solid line) simulated under (a) constant birth-death, (b) increasing speciation-rate, and (c) recent mass-extinction models and their jackknifed trees (dashed lines) at 90%, 80%, 70%, 60%, 50%, and 40% are plotted. As the tree moves further from complete, the density plot shifts left, as a result of a declining principal 位, and the shape of the spectral density becomes increasingly different from the original, notably by decreasing skewness. The mean and standard deviation of the Jensen-Shannon distance between each tree and its 100 jackknifed trees are shown in a barplot. The distance between trees increases linearly with incompleteness
