Dynamics of speciation and diversification in a metapopulation

We develop a simple framework for modeling speciation and diversification a s a continuous process of accumulation of genetic (or morphological) differ ences accompanied by species and subpopulation extinction and/or range expa nsion. This framework can be used to approach a number of questions such as species-area distribution, species-range size distribution, the rate of ec ological turnover, asymmetries of range division between sister species, wa iting time until speciation and extinction, the relationship between the ge ographic range size and the probability of speciation, the relationships be tween subpopulation-level parameters and metapopulation-level parameters, a nd the effects of taxonomic level on these rates, distributions, and parame ters. We illustrate some of these applications using numerical simulations. We develop approximations describing the dependence of the number of diffe rent taxonomic units, their average range size, and the rate of their turno ver on the system size, the rate of fixation of genetic (or morphological) changes in local demes, and the rate of local extinction and colonization.