rise in elevation is the rough equivalent of a 

 150-mile journey away from the equator — so 

 ecosystems in the mountains get stacked verti- 

 cally. And the land area decreases as you climb, 

 so new climate zones at successively higher 

 n1fv:it-irm<; arf mnfinrd rr> surcpssivelv smaller 



his neck like a religious medal, and sets his 

 sleeping bag out under the stars most nights. 



The co-leader of our expedition is Anton 

 Seimon, a Columbia University geographer 

 and climber who has organized scientific treks 

 like this one through the Vilcanotas for the past 



plots. The highest zone, the alpine zone, covers 

 only 3 percent of Earth's landmass, yet perhaps 

 10,000 plant species live there — many evolving 

 on just one or two islandlike peaks, separated 

 by oceans of lowlands. 



five years. In 2004 he and his wife Tracie A. 

 Seimon, a cell biologist also at Columbia, dis- 

 covered tiny, unidentified tadpoles near our 

 pond — apparently the world's highest known 

 amphibians. Sowell and I hope to spot adults, 

 to prove they are breeding here. 



H alloy, an alpine ecologist who consults for 

 the World Wildlife Fund and teaches at 

 San Andres University in La Paz, Bolivia, seems 

 specially evolved, too. A Belgian raised in Africa, 

 the United States, and Argentina, he was just 



fv\-p.Krr> wVipii stnrffH h^lnintr his hprnpfnlo- 



to prove they are breeding here. 



The higher you go, of course, the thinner the 

 air. Animals and peoples of the high Andes 

 (and in other high regions such as the Hima- 

 layas and the high Ethiopian plateau) have 

 evolved bigger lungs or beefed-up blood chem- 

 isrrv for delivering more oxveren. Manv low- 



twelve when he started helping his herpetolo- 

 gist father with high-elevation work. While oth- 

 ers in our party labor upward with heavy boots 

 and trekking poles, and sleep in all-weather 

 tents, he lopes along in frail canvas sneakers, 

 hands behind his back, chatting away as if giv- 



istry for delivering more oxygen. Many low- 



High-alpine environment is home to a surprising variety of life-forms. The ter- 

 rain shown in this view, looking west from Mount Sajama, a dormant volcano 

 in Bolivia, is typical. In the background are the twin volcanoes Parinacota (left) 

 and Pomerape, which lie on the border between Bolivia and Chile. Both are 

 more than 20,000 feet high. 



September 2006 N at U I*. A I HISTORY 45 



