BY THE NEXT MORNING, the team was clear on what they should focus on: Sulfolobus and Acidianus, the extreme heat-and acid-loving prokaryotes first discovered in Yellowstone National Park.

Why focus on these thermoacidophilic organisms? Tom: "There's a lot easier access here to information on hot pots, because there are scientists around here who do studies, and the hot pots are really close by." Eric: "I was able to find good information right away." Jamie: "Life on Mars - it's pretty cool to think about, but there's just not so much information. It takes six months just to get there, and they can only do certain kinds of tests and stuff." Because the team was from the Montana area, they were all familiar with Yellowstone's hot spring features, where the life was found.

Their chosen topic also is historically significant, because in many ways Thomas Brock's discovery of the Sulfolobus and Acidianus organisms began the search for life in extreme environments that continues to this day. And if you plot the range of life forms on a graph, the two organisms occupy a niche at the far end of two extremes: in an environment both very hot and very acidic.

"They live in boiling acid!" Justin said. "That's pretty extreme."

MORE: "The Extremes Of Life" Graph