416 



THE CHANGING GENERATIONS 



gave rise to several lines of herbivorous dinosaurs in the Cretaceous; but 

 such plants are poor fare. It was the angiosperms that made available 

 the first abundant and nutritious plant food — seeds, fruits, nuts, and 

 edible foliage in limitless quantity — and thus opened the way for a 

 tremendous increase in the amount of animal life which the lands could 



Fig. 26.16. A Triassic forest of giant pines, with an undergrowth of cycads. (Courtesy 

 American Museum, of Natural History.) 



support. With the rise of flowering plants to dominance, many groups of 

 animals became herbivores and multiplied in kind and number, as did the 

 carnivores that fed upon them. The rapid evolution of the mammals and 

 birds followed and was made possible by the evolution of the flowering 

 plants. 



Forests continued to dominate the scene until midway through the 

 following Cenozoic era. Meanwhile the ancestral Rocky Mountains and 



