Desert DiaryOctober 3, 2001
Desert Diary
Plants/Grass
It s hard for us to imagine a world without grass, yet as major plant groups go, it's the new kid on the block. Visualize the landscape inhabited by dinosaurs, but leave out grasses. The last dinosaur died about 65 million years ago, and our earliest fossil grass evidence seems to date about 3 million years later.
It's difficult to overestimate the importance of grasses to humans and to wildlife in general. Estimates are that somewhere around two-thirds of human calorie intake is from grasses--such as wheat, barley, and corn.
Over 20 million years ago, forested areas began to be replaced by open grasslands--to the point that today, grasslands are estimated to cover some 25% of the earth's land surface. Numerous North American mammals responded evolutionarily to the new environmental pressures by specializing for outrunning predators in the open landscape and by developing dentition fit for a grass diet. The next time you see one of our desert Pronghorns or Bighorn Sheep, marvel at what a simple plant has wrought.
Audio. To hear the audio from the broadcast, you need to be using Internet Explorer and have RealPlayer, a free download (go to near the bottom of the RealPlayer page and download RealPlayer 8 basic).
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
