Featured Research

from universities, journals, and other organizations

Equatorial Water May Have Provided Means Of Survival

June 5, 2000
University Of Toronto
To improve a child's likelihood of succeeding at school, educators need a better understanding of the strengths and weaknesses of the IQ test, says a University of Toronto psychiatry professor.

Sudden warming trends melted ice, providing refuge for multi-celled animals while the rest of the Earth was frozen

The precursor of modern animals may have been able to survive a Snowball Earth era that occurred some 600 million years ago because of a belt of open water along the equator, suggests scientists from the University of Toronto and Texas A&M University. This was a time considered critical in the evolutionary development of multi-celled animals and therefore the most important interval for biological evolution in general.

In a paper to be published in the May 25 edition of Nature, University of Toronto physics professor Richard Peltier and Texas A&M oceanographers William Hyde, Thomas Crowley and Steven Baum note that the late Proterozoic era (600-800 million years ago) was the most important period of evolution for multi-cellular creatures. However, this period was also a time in Earth's history that has come to be referred to as the Snowball Earth. At that time, the planet was thought to be completely ice-covered. Geological and paleomagnetic evidence indicates that for alternating periods, the Earth was completely covered by ice sheets over the continents and sea ice over the oceans, followed by sudden warming trends that melted the ice.

"If the suface of the planet was covered by ice, the question arises as to how early life managed to survive under such environmental stress," says Peltier. To find an answer, the scientists employed several different models of the climate systems and ran detailed computer simulations of the climate thought to have been characteristic of that time. To simulate the Snowball Earth, they reduced the amount of sunlight reaching the Earth -- to account for the fact that the sun was about six per cent less luminous than it is now -- and varied the concentration of atmospheric carbon dioxide within the range expected for that time.

In most of the simulations, their analysis revealed the presence of a belt of open water near the equator when the general circulation of the ocean was taken into account. "It is this open water that may have provided a refuge for multi-celled animals when the rest of the Earth was covered by ice and snow," Peltier explains.

The findings of this research are critical to understanding how early life evolved, he states. "This could help clarify how multi-celled animals managed not only stay alive, but to thrive given the Earth's harsh conditions. The extreme climates may even have exerted pressure on these animals to evolve and adapt, possibly leading to the rapid development of new forms of animals and their movement into new, unpopulated habitats when the Earth exited the snowball state. It was during the warm Cambrian era -- immediately following the late Proterozoic -- in which life proliferated."

The late Proterozoic period was also a time when the supercontinents Rodinia and Pannotia formed and subsequently rifted and disassembled. Located over the south rotational pole in the position of present-day Antarctica, these supercontinents were made up of the current land masses of Africa, South America, Antarctica, Australia, Greenland, Laurentia and parts of Asia. According to Peltier, the entry of the Earth into the snowball state required not only the weak sun and atmospheric carbon dioxide levels not significantly higher than present-day, but also this high degree of polar continentality.

Funding for this research came from the Natural Sciences and Engineering Research Council of Canada and the National Science Foundation in the U.S.

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. "Equatorial Water May Have Provided Means Of Survival." ScienceDaily. ScienceDaily, 5 June 2000. <www.sciencedaily.com/releases/2000/05/000529093616.htm>.
University Of Toronto. (2000, June 5). Equatorial Water May Have Provided Means Of Survival. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2000/05/000529093616.htm
University Of Toronto. "Equatorial Water May Have Provided Means Of Survival." ScienceDaily. www.sciencedaily.com/releases/2000/05/000529093616.htm (accessed September 1, 2014).

Share This

More Earth & Climate News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Reuters - US Online Video (Aug. 30, 2014) An animal rescue in Washington state receives an influx of orphaned squirrels, keeping workers busy as they nurse them back to health. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Raw: Small Volcanic Eruption in Iceland

Raw: Small Volcanic Eruption in Iceland

AP (Aug. 29, 2014) Icelandic authorities briefly raised the aviation warning code to red on Friday during a small eruption at the Holuhraun lava field in the Bardabunga volcano system. (Aug. 29) Video provided by AP
Powered by NewsLook.com
As Drought Continues LA "water Police" Fight Waste

As Drought Continues LA "water Police" Fight Waste

AFP (Aug. 29, 2014) In the midst of a historic drought, Los Angeles is increasing efforts to go after people who waste water. Five water conservation "cops" drive around the city every day educating homeowners about the drought. Duration: 02:17 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.


Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


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