For example, hoofed animals with longer necks could reach the juiciest leaves on tall trees and therefore tended to eat well, live longer, and have more offspring. Eventually, they evolved into giraffes. Those with shorter necks died out. Woops! Looks like somebody forgot to tell the Zebras, Wildebeasts, and a dozens of different antelope like animals that they died out...
I enjoy evolutionary theories for the humor! :)
Yeah, but you should have seen the old models-no necks! Things looked like some kind of spokesperson for NOW. Now they've all got necks, much more shapely.