. Earth Science News .




.
FLORA AND FAUNA
Castaway lizards provide insight into elusive evolutionary process
by Staff Writers
Kingston RI (SPX) Feb 07, 2012

File image.

A University of Rhode Island biologist who released lizards on tiny uninhabited islands in the Bahamas has shed light on the interaction between evolutionary processes that are seldom observed.

Jason Kolbe, a URI assistant professor of biological sciences, and colleagues from Duke University, Harvard University and the University of California at Davis, found that the lizards' genetic and morphological traits were determined by both natural selection and a phenomenon called founder effects, which occur when species colonize new territory.

Their research was published in the journal Science.

"We rarely observe founder effects as they happen in nature, but we know that it happens because islands are colonized by new species over time," said Kolbe.

"What we didn't know was how these evolutionary mechanisms interact with each other. What we learned is that the differences caused by the founder effects persist even as populations adapt to their new environments."

The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It often results in the new population becoming genetically or morphologically different from the original population.

The scientists randomly collected brown anole lizards from a large island near Great Abaco and released one pair on each of seven nearby islands whose lizard populations had been cleared by a recent hurricane. The source island is forested while the other islands have short, scrub vegetation.

Previous research found that anoles living in forests had longer hind limbs than those found in scrub habitat. Lizards with longer limbs can run faster on the broad perches available in forests, while short-limbed lizards are more adept at moving on the narrower perches found in lower vegetation.

The scientists revisited each of the islands over the next four years to measure the lizards' limb length and collect tissue samples for genetic analysis. All of the new populations survived and increased an average of 13-fold in the first two years before leveling off.

"We noticed a founder effect one year after starting the experiment, which resulted in differences among the lizards on the seven islands," Kolbe said. "Some of the islands had lizards with longer limbs and some had lizards with shorter limbs, but that was random with respect to the vegetation on the new islands."

Because the structure of the vegetation on the islands differed from that of the source island, the scientists predicted that natural selection would lead the lizards to develop shorter limbs.

"Over the next four years, the lizards on all the islands experienced a decrease in leg length that is attributable to natural selection," Kolbe explained.

"But those that started out with the longest hind limbs still had the longest hind limbs. The fact that the populations maintained their order from longest to shortest limbs throughout the experiment means that both founder effects and natural selection contributed to their current differences."

According to Kolbe, founding effects are rarely observed in nature, with most previous studies being conducted in the laboratory.

"Ours is the first to study this process experimentally in a natural setting, and we were able to account for multiple evolutionary mechanisms through time," he said. "We manipulated the founding of these islands, but everything else about it was natural."

The next step in the research will be to determine how long the founder effects persist before other factors erase its signature.

Related Links
University of Rhode Island
Darwin Today At TerraDaily.com




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries






.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



FLORA AND FAUNA
Castaway Lizards Offer New Look at Evolutionary Processes
Durham NC (SPX) Feb 07, 2012
Biologists who released lizards on tiny uninhabited islands in the Bahamas have uncovered a seldom-observed interaction between evolutionary processes. Jason Kolbe, a biologist at the University of Rhode Island (URI)--along with colleagues at Duke University, Harvard University and the University of California, Davis--found that the lizards' genetic and morphological (form and structural) ... read more


FLORA AND FAUNA
FLORA AND FAUNA
3D printer creates new jaw for woman

Phobos Crash Test Dismisses U.S. Link

iPhone leaps to third place in mobile market

Apple's iPhone hot but Android handsets on fire

FLORA AND FAUNA
FLORA AND FAUNA
Land-cover changes do not impact glacier loss

FLORA AND FAUNA
Nearly half China farmers suffer land grabs: report

FLORA AND FAUNA
Philippine rescuers search for quake survivors

Flood fears ease in Australia as clean-up begins

FLORA AND FAUNA
Explosion rocks military barracks in northern Nigeria

S.Africa's strike-hit Kruger Park to hire retired rangers

FLORA AND FAUNA

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement