01624nas a2200193   4500008004100000020001400041245011100055210006900166260001200235300001400247490000700261520104300268653000901311653002201320653002201342100001601364700002601380856002401406       2008                        eng d  a1461-023X00aThe tropics: cradle, museum or casino? A dynamic null model for latitudinal gradients of species diversity0 atropics cradle museum or casino A dynamic null model for latitud  c2008///  a653 - 6630 v113 aSeveral ecological and evolutionary hypotheses have been proposed to explain the latitudinal diversity gradient (LDG), but a general model for this conspicuous pattern remains elusive. Mid-domain effect (MDE) models generate gradients of species diversity by randomly placing the geographic ranges of species in one- or two-dimensional spaces, thus excluding both evolutionary processes and the effect of contemporary climate. Traditional MDE models are statistical and static because they determine the size of ranges either randomly or based on empirical frequency distributions. Here we present a simple dynamic null model for the LDG that simulates stochastic processes of range shifts, extinction and speciation. The model predicts higher species diversity and higher extinction and speciation rates in the tropics, and a strong influence of range movements in shaping the LDG. These null expectations should be taken into consideration in studies aimed at understanding the many factors that generate latitudinal diversity gradients10aSIZE10aspecies diversity10aSPECIES-DIVERSITY1 aArita, H.T.1 aVazquez-Dominguez, E.  uISI:000256376900001