Charles Darwin explained how species emerge and disappear, but he didn't know about genes -- the biological currency that makes evolution possible. Today we know that the more genetically diverse a species is, the more likely it is to survive various threats, such as a warming or shrinking habitat. Diverse populations are more likely to contain individuals that can pass on preferential traits, enabling a species to evolve and live on. Unfortunately, that doesn't always happen. Now Richard Gomulkiewicz at Washington State University and David Houle of Florida State University have developed a set of formulas that mathematically marry rates of habitat destruction, population change, genetic variability, and other factors, enabling them to predict whether a species is on track for extinction.

It's difficult for ecologists to factor evolution into their projections for a species' future habitat needs, Gomulkiewicz explains, adding that these formulas constitute a model that "tells you when it just won't be possible [for a species to avoid extinction]." The model could be refined and employed by field biologists in the future, and may one day help wildlife advocates and federal officials to prioritize scant resources and focus on imperiled species with better chances of survival.