Featured Research

from universities, journals, and other organizations

Evolutionary Change Leapfrogs Over Tadpoles

Date:
March 29, 2000
Source:
University Of Toronto
Summary:
Scientists at the University of Toronto have discovered a species of frog that skips the tadpole phase of development but still requires a thyroid to grow into fully formed adults.

Newly discovered species of frog bypasses the tadpole phase of development

University of Toronto scientists have recently discovered a species of frog that skips the tadpole phase of development but still requires a thyroid to grow into fully formed adults.

"We already knew that many frogs - mostly in tropical zones - bypass the tadpole stage and hatch from eggs as tiny versions of mature adults," says zoology professor Richard Elinson, who co-authored a paper with former doctoral student Elizabeth Callery. "But the question was 'How did they manage to do it?' Since a tadpole requires thyroid hormone to mature into an adult, was the hormone eliminated along with the tadpole phase? It had been assumed that this other species developed without a thyroid hormone but we've shown they still have a thyroid-dependent state."

Elinson calls this a classic case of evolutionary change in development. The theory is that this species, found in the tropics of Puerto Rico, evolved over millions of years to the point where it retained the hormone but lost its tadpole phase. In other words, he says, these frogs devised ways to evade dangerous living conditions in water containing predators - their mating occurs on land, fertilization happens in the body of the female and eggs are laid and hatched on land

The paper, titled Thyroid Hormone-Dependent Metamorphosis in a Direct Developing Frog, is featured in the March 14 issue of Proceedings of the National Academy of Sciences of the United States of America.

CONTACT:
Janet Wong
U of T Public Affairs
(416) 978-6974
jf.wong@utoronto.ca


Story Source:

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


Cite This Page:

University Of Toronto. "Evolutionary Change Leapfrogs Over Tadpoles." ScienceDaily. ScienceDaily, 29 March 2000. <www.sciencedaily.com/releases/2000/03/000328152247.htm>.
University Of Toronto. (2000, March 29). Evolutionary Change Leapfrogs Over Tadpoles. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2000/03/000328152247.htm
University Of Toronto. "Evolutionary Change Leapfrogs Over Tadpoles." ScienceDaily. www.sciencedaily.com/releases/2000/03/000328152247.htm (accessed September 19, 2014).

Share This



More Plants & Animals News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
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:
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