02.26.06
Rapid evolution
Global Warming Fuels Speedy Evolution
Date: 27 Feb 2006
By Larry O’Hanlon, Discovery News
Feb. 22, 2006 — Don’t look now, but your backyard is evolving. It’s no joke. There’s a growing body of evidence that evolution is no longer something only seen either in this year’s flu virus or Cretaceous tyrannosaur bones. It’s happening everywhere, right now, and charging full-steam ahead.
Research on toads, frogs, salamanders, fish, lizards, squirrels and plants are all showing evidence that some species are attempting to adapt to new conditions in a time frame of decades, not eons, say biologists.
What’s more, one of the biggest reasons for all this evolution right now may be that human-induced changes to climate and landscapes give species few other options.
“Basically, a species can do three things,” said the University of Sydney’s Richard Shine: “go extinct, move or adapt.”
The first two have kept conservation biologists working day and night, to the exclusion of the third, he said. But that’s changing as real-time evolution is hitting the news wires and getting more attention.
The highest-profile case yet was made public by Shine and his colleagues in the Feb. 16 issue of Nature: the case of toxic cane toads at the forefront of a seven-decade Australian invasion. Measurements over the years prove that the leading toads have evolved significantly longer legs.
It appears that hopping further and faster rewards long-legged toads with the first crack at lush virgin territory, and therefore more offspring to perpetuate their athleticism.
Behind that story are even more cases of rapid evolution, says Shine, an evolutionary ecologist. Already he’s seeing changes in native Australian snakes. First they tried to eat the toads, and died. Now, Shine says, the surviving snakes have modified jaws which make them unable to eat the toads and therefore safe from their toxin.
“Invasive species are a nice model,” Shine said.
They hint at the rates of evolution that might be expected as species feel the increasing pressure of global warming. They also draw the attention of conservation biologists, who are often on the front lines of battles to save habitats and individual species.
“In the past 20 years, essentially all evolutionary biologists have come to widely recognize the importance and prevalence of (what’s) often called ‘rapid evolution,’” wrote evolutionary biologist Andrew Hendry of McGill University, who responded to questions via email from the Galapagos Islands. “Many conservation biologists have recently come to the same realization and I expect that the rest will soon follow.”
Rapid evolution is good news for conservation biologists. It implies that the number of species that might go extinct will be less than some current estimates, which predict as many as one-third of all species alive today will be wiped out by 2050.