Data from: Simple versus complex models of trait evolution and stasis as a response to environmental change

Previous analyses of evolutionary patterns, or modes, in fossil lineages
have focused overwhelmingly on three simple models: stasis, random walks,
and directional evolution. Here we use likelihood methods to fit an
expanded set of evolutionary models to a large compilation of
ancestor–descendant series of populations from the fossil record. In
addition to the standard three models, we assess more complex models with
punctuations and shifts from one evolutionary mode to another. As in
previous studies, we find that stasis is common in the fossil record, as
is a strict version of stasis that entails no real evolutionary changes.
Incidence of directional evolution is relatively low (13%), but higher
than in previous studies because our analytical approach can more
sensitively detect noisy trends. Complex evolutionary models are often
favored, overwhelmingly so for sequences comprising many samples. This
finding is consistent with evolutionary dynamics that are, in reality,
more complex than any of the models we consider. Furthermore, the timing
of shifts in evolutionary dynamics varies among traits measured from the
same series. Finally, we use our empirical collection of evolutionary
sequences and a long and highly resolved proxy for global climate to
inform simulations in which traits adaptively track temperature changes
over time. When realistically calibrated, we find that this simple model
can reproduce important aspects of our paleontological results. We
conclude that observed paleontological patterns, including the prevalence
of stasis, need not be inconsistent with adaptive evolution, even in the
face of unstable physical environments.