Featured Research

from universities, journals, and other organizations

Castaway lizards provide insight into elusive evolutionary process, founder effects

Date:
February 2, 2012
Source:
University of Rhode Island
Summary:
A biologist who released lizards on tiny uninhabited islands in the Bahamas has shed light on the interaction between evolutionary processes that are seldom observed. He 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.

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.
Credit: Image courtesy of University of Rhode Island

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 recently 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.

The study was funded by the National Science Foundation and the National Geographic Society.


Story Source:

The above story is based on materials provided by University of Rhode Island. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jason J. Kolbe, Manuel Leal, Thomas W. Schoener, David A. Spiller, and Jonathan B. Losos. Founder Effects Persist Despite Adaptive Differentiation: A Field Experiment with Lizards. Science, 2 February 2012 DOI: 10.1126/science.1209566

Cite This Page:

University of Rhode Island. "Castaway lizards provide insight into elusive evolutionary process, founder effects." ScienceDaily. ScienceDaily, 2 February 2012. <www.sciencedaily.com/releases/2012/02/120202151131.htm>.
University of Rhode Island. (2012, February 2). Castaway lizards provide insight into elusive evolutionary process, founder effects. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2012/02/120202151131.htm
University of Rhode Island. "Castaway lizards provide insight into elusive evolutionary process, founder effects." ScienceDaily. www.sciencedaily.com/releases/2012/02/120202151131.htm (accessed April 23, 2014).

Share This



More Plants & Animals News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Leopard Bites Man in India

Raw: Leopard Bites Man in India

AP (Apr. 22, 2014) A leopard caused panic in the city of Chandrapur on Monday when it sprung from the roof of a house and charged at rescue workers. (April 22) Video provided by AP
Powered by NewsLook.com
Iowa College Finds Beauty in Bulldogs

Iowa College Finds Beauty in Bulldogs

AP (Apr. 22, 2014) Drake University hosts 35th annual Beautiful Bulldog Contest. (April 21) Video provided by AP
Powered by NewsLook.com
805-Pound Shark Caught Off The Coast Of Florida

805-Pound Shark Caught Off The Coast Of Florida

Newsy (Apr. 22, 2014) One Florida fisherman caught a 805-pound shark off the coast of Florida earlier this month. Video provided by Newsy
Powered by NewsLook.com
Breakfast Foods Are Getting Pricier

Breakfast Foods Are Getting Pricier

AP (Apr. 21, 2014) Breakfast is now being served with a side of sticker shock. The cost of morning staples like bacon, coffee and orange juice is on the rise because of global supply problems. (April 21) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Caribbean Lizards Settle 'founder Effect' Controversy

Feb. 2, 2012 In the first experimental study of the founder effect in a natural setting, researchers found that natural selection does not overwhelm the founder ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins