Table 1: Models of the evolutionary trajectory of a community

From: Speedy speciation in a bacterial microcosm: new species can arise as frequently as adaptations within a species

ModelParametersExpected ratio (r) at time t
 Initial MT:LT ratio (r0)Waiting time (tw)Slope of change in ratio (m)Steady-state ratio of two ecotypes (r) 
NullYesNoNoNor=r0 over all times
Single-ecotypeYesYesYesNor=r0 until time tw; log r=log r0+m (t - tw) after tw
Multi-ecotypeYesYesYesYesr=r0 until time tw; log r=log r0+m (t - tw) after tw and before r reaches r; r=r after r reaches r
  1. The initial-ratio parameter r0 was estimated directly from the initial MT and LT colony counts; the parameters for waiting time (tw), slope (m) and the steady-state ratio (r) were estimated to fit the observed trajectories of MT:LT ratio with maximum likelihood, as described in the text. The likelihood of the model yielding an observed ratio at a given time was based on the empirical Gaussian distribution of the ratio (Supplementary Figure 1). Yes and no indicate whether a parameter was included within a given model.