Word: poulson
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Dates: during 1990-1999
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Caves have led to new insights about evolution. The absence of light and scarcity of food limit the number of species that can survive underground. Most common are crickets, beetles and eyeless fish. "We see simple communities that may be made up of only four species," says Tom Poulson, professor of biology at the University of Illinois at Chicago. "But that allows us to look in greater detail at what is going on, say, between predator / and prey." As a result, biologists can study subterranean ecosystems in their entirety -- a feat that often proves impossibly complex aboveground...
...they and their descendants traveled deeper inside and away from sunlight, they began to lose their eyes and develop other sensory organs to compensate. But is this loss an active process or just a question of disuse? "That's been a raging debate ever since Darwin's time," Poulson says. "What we've found is that it's disuse. There is no natural selection to screen out any bad mutations that affect the eyes. So eventually they disappear...