Common misconceptions of speciation.

Abstract

Speciation is a complex process that can unfold in many different ways. Speciation researchers sometimes simplify core principles in their writing in a way that implies misconceptions about the speciation process. While we think that these misconceptions are usually inadvertently implied (and not actively believed) by the researchers, they nonetheless risk warping how external readers understand speciation. Here we highlight six misconceptions of speciation that are especially widespread. First, species are implied to be clearly and consistently defined entities in nature, whereas in reality species boundaries are often fuzzy and semipermeable. Second, speciation is often implied to be 'good', which is two-fold problematic because it implies both that evolution has a goal and that speciation universally increases the chances of lineage persistence. Third, species-poor clades with species-rich sister clades are considered 'primitive' or 'basal', falsely implying a ladder of progress. Fourth, the evolution of species is assumed to be strictly tree-like, but genomic findings show widespread hybridization more consistent with network-like evolution. Fifth, a lack of association between a trait and elevated speciation rates in macroevolutionary studies is often interpreted as evidence against its relevance in speciation-even if microevolutionary case studies show that it is relevant. Sixth, obvious trait differences between species are sometimes too readily assumed to be (i) barriers to reproduction, (ii) a stepping-stone to inevitable speciation, or (iii) reflective of the species' whole divergence history. In conclusion, we call for caution, particularly when communicating science, because miscommunication of these ideas provides fertile ground for misconceptions to spread.