The neutral theory of biodiversity purports that patterns in the distribution and abundance of species do not depend on adaptive differences between species (i.e. niche differentiation) but solely on random fluctuations in population size (“ecological drift”), along with dispersal and speciation. In this framework, the ultimate driver of biodiversity is speciation. However, the original neutral theory made strongly simplifying assumptions about the mechanisms of speciation, which has led to some clearly unrealistic predictions. In response, several recent studies have combined neutral (...) community models with more elaborate speciation models. These efforts have alleviated some of the problems of the earlier approaches, while confirming the general ability of neutral theory to predict empirical patterns of biodiversity. However, the models also show that the mode of speciation can have a strong impact on relative species abundances. Future work should compare these results to diversity patterns arising from non‐neutral modes of speciation, such as adaptive radiations. (shrink)

Mitochondrial bioenergetics plays a key role in multiple basic cellular processes, such as energy production, nucleotide biosynthesis, and iron metabolism. It is an essential system for animals' life and death (apoptosis) and it is required for embryo development. This, in conjunction with its being subjected to adaptive processes in multiple species and its gene products being involved in the formation of reproductive barriers in animals, raises the possibility that mitochondrial bioenergetics could be a candidate genetic mechanism of speciation. Here, we (...) discuss genetic and biochemical evidence for the possible involvement of this unique system, encoded by two genomes (the mitochondrial and nuclear genomes), that differ by an order of magnitude in their mutation rates in processes leading to speciation events. (shrink)