Figure I b in Box 2 of Ricklefs (2007) is really blowing my mind. Are the NA and SA clades just placed on top of each other, or is there some interaction there? I see that there's likelihood ratios in there, but thats about as far as I get...
The plots show the likelihood of different combinations of parameter values of speciation rate and the ratio of speciation to extinction (expressed as the number of likelihood units below the maximum likelihood). I take too things from this graph: (1) a fairly large range of speciation rates fit approximately equally well if different ratios of speciation to extinction are assumed (2) Despite this, there is a clear difference in the diversification rate of the two regions because for a given value of the speciation rate plausible estimates of the ratio of extinction to speciation are higher for NA, implying lower net diversification. The two plots are on the same scale. I think the reason why he chose to superimpose them rather than plotting the full likelihood surface for each area separately was to highlight the fact that likely values for the two regions do not overlap.
The plots show the likelihood of different combinations of parameter values of speciation rate and the ratio of speciation to extinction (expressed as the number of likelihood units below the maximum likelihood). I take too things from this graph: (1) a fairly large range of speciation rates fit approximately equally well if different ratios of speciation to extinction are assumed (2) Despite this, there is a clear difference in the diversification rate of the two regions because for a given value of the speciation rate plausible estimates of the ratio of extinction to speciation are higher for NA, implying lower net diversification. The two plots are on the same scale. I think the reason why he chose to superimpose them rather than plotting the full likelihood surface for each area separately was to highlight the fact that likely values for the two regions do not overlap.
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