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When evolution is not so slow and gradual
June 03, 2009Study finds guppies adapt to new surroundings in just a few years
What's the secret to surviving during times of environmental change? Evolve-quickly.
A new article in The American Naturalist finds that guppy populations introduced into new habitats developed new and advantageous traits in just a few years. This is one of only a few studies to look at adaptation and survival in a wild population.
A research team led by Swanne Pamela Gordon from the University of California, Riverside studied 200 guppies that had been taken from the Yarra River in Trinidad and introduced into two different environments in the nearby Damier River, which previously had no guppies. One Damier environment was predator-free. The other contained fish that occasionally snack on guppies.
Eight years after their introduction, the team revisited the Damier guppies to see what adaptive changes they might have picked up in their new environments. The researchers found that the females had altered their reproductive effort to match their surroundings. In the environment where predators were present, females produced more embryos each reproductive cycle. This makes sense because where predators abound, one might not get a second chance to reproduce. In less dangerous waters, females produced fewer embryos each time, thus expending fewer resources on reproduction.
Finally, the researchers wanted to see if these adaptive changes actually helped the new population to survive. So they took more guppies from the Yarra, marked them, and put them in the Damier alongside the ones that had been there for eight years. They found that the adapted guppies had a significant survival advantage over the more recently introduced group.
In particular, juveniles from the adapted population had a 54 to 59 percent increase in survival rate over those from the newly introduced group. In the long run, survival of juveniles is crucial to the survival of the population, the researchers say.
The fact that fitness differences were found after only eight years shows just how fast evolution can work-for short-lived species anyway.
"The changes in survival in our study may initially seem encouraging from a conservation perspective," the authors write. "[B]ut it is important to remember that the elapsed time frame was 13-26 guppy generations. The current results may therefore provide little solace for biologists and managers concerned with longer-lived species."
University of Chicago Press Journals
A research team led by Swanne Pamela Gordon from the University of California, Riverside studied 200 guppies that had been taken from the Yarra River in Trinidad and introduced into two different environments in the nearby Damier River, which previously had no guppies. One Damier environment was predator-free. The other contained fish that occasionally snack on guppies.
Eight years after their introduction, the team revisited the Damier guppies to see what adaptive changes they might have picked up in their new environments. The researchers found that the females had altered their reproductive effort to match their surroundings. In the environment where predators were present, females produced more embryos each reproductive cycle. This makes sense because where predators abound, one might not get a second chance to reproduce. In less dangerous waters, females produced fewer embryos each time, thus expending fewer resources on reproduction.
Finally, the researchers wanted to see if these adaptive changes actually helped the new population to survive. So they took more guppies from the Yarra, marked them, and put them in the Damier alongside the ones that had been there for eight years. They found that the adapted guppies had a significant survival advantage over the more recently introduced group.
In particular, juveniles from the adapted population had a 54 to 59 percent increase in survival rate over those from the newly introduced group. In the long run, survival of juveniles is crucial to the survival of the population, the researchers say.
The fact that fitness differences were found after only eight years shows just how fast evolution can work-for short-lived species anyway.
"The changes in survival in our study may initially seem encouraging from a conservation perspective," the authors write. "[B]ut it is important to remember that the elapsed time frame was 13-26 guppy generations. The current results may therefore provide little solace for biologists and managers concerned with longer-lived species."
University of Chicago Press Journals
Evolution Current Events and Evolution News RSSWe're off then: the evolution of bat migration
Not just birds, but also a few species of bats face a long journey every year. Researchers at Princeton University in the U.S. and at the Max Planck Institute for Ornithology in Radolfzell, Germany studied the migratory behaviour of the largest extant family of bats, the so-called "Vespertilionidae" with the help of mathematical models.
Insect Resistance to Bt Crops can be Predicted, Monitored, and Managed
Since 1996, crop plants genetically modified to produce bacterial proteins that are toxic to certain insects, yet safe for people, have been planted on more than 200 million hectares worldwide.
Multiple health concerns surface as winter, vitamin D deficiences arrive
A string of recent discoveries about the multiple health benefits of vitamin D has renewed interest in this multi-purpose nutrient, increased awareness of the huge numbers of people who are deficient in it, spurred research and even led to an appreciation of it as "nature's antibiotic."
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago
A new study provides "incontrovertible evidence" that the volcanic super-eruption of Toba on the island of Sumatra about 73,000 years ago deforested much of central India, some 3,000 miles from the epicenter, researchers report.
Is global warming unstoppable?
In a provocative new study, a University of Utah scientist argues that rising carbon dioxide emissions - the major cause of global warming - cannot be stabilized unless the world's economy collapses or society builds the equivalent of one new nuclear power plant each day.
Scientists at UA, collaborating institutions decode maize genome
Scientists from the University of Arizona led by Arizona Genomics Institute director Rod A. Wing and from collaborating institutions have deciphered the complete genetic code of the maize plant for the first time.
New Maize Map to Aid Plant Breeding Efforts
In a massive survey of genetic diversity in maize, also known as corn, researchers across the United States, have developed a gene map that should pave the way to significant improvements in a plant that is a major source of food, fuel, animal feed and fiber around the world.
'Hobbits' are a new human species -- according to the statistical analysis of fossils
Researchers from Stony Brook University Medical Center in New York have confirmed that Homo floresiensis is a genuine ancient human species and not a descendant of healthy humans dwarfed by disease.
Research challenges for understanding landscape changes identified
Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled today in a new report by the National Research Council.
Scientists Unravel Evolution of Highly Toxic Box Jellyfish
With thousands of stinging cells that can emit deadly venom from tentacles that can reach ten feet in length, the 50 or so species of box jellyfish have long been of interest to scientists and to the public. Yet little has been known about the evolution of this early branch in the animal tree of life.
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