Data from: Phenotypic determinism and contingency in the evolution of hypothetical tree-like organisms

Whether evolutionary history is mostly contingent or deterministic has
been given much focus in the field of evolutionary biology. Studies
addressing this issue have been conducted theoretically, based on models,
and experimentally, based on microcosms. It has been argued that the shape
of the adaptive landscape and mutation rate are major determinants of
replicated phenotypic evolution. In the present study, to incorporate the
effects of phenotypic plasticity, we constructed a model using tree-like
organisms. In this model, the basic rules used to develop trees are
genetically determined, but tree shape (described by the number and aspect
ratio of the branches) is determined by both genetic components and
plasticity. The results of the simulation show that the tree shapes become
more deterministic under higher mutation rates. However, the tree shape
became most contingent and diverse at the lower mutation rate. In this
situation, the variances of the genetically determinant characters were
low, but the variance of the tree shape is rather high, suggesting that
phenotypic plasticity results in this contingency and diversity of tree
shape. The present findings suggest that plasticity cannot be ignored as a
factor that increases contingency and diversity of evolutionary
outcomes.