244 



Origin of Biomes and Succession 



dreds of different but closely related species. That such events have 

 happened in the past can be demonstrated by comparing geologic 

 maps for successive times (Fig. 104). 



Present-day communities give abundant evidence of community 

 fission. The biotas of central Florida and of south central Texas have 



Late Mississippion 



Early Pennsylvanion 



Late Pennsylvonion 



Eorly Permian 



Fig. 104. Successive paleographic maps of North America showing alternate 

 fission and reunion of both terrestrial and marine community sites. (Adapted 

 from Dunbar, Historical Geology, 2nd. Ed., John Wiley & Sons, 1960.) 



