Featured Research

from universities, journals, and other organizations

Oxygen Increase Caused Mammals To Triumph, Researchers Say

Date:
October 3, 2005
Source:
Rutgers, the State University of New Jersey
Summary:
The first, high resolution continuous record of oxygen concentration in the earth's atmosphere shows that a sharp rise in oxygen about 50 million years ago gave mammals the evolutionary boost they needed to dominate the planet, according to Paul Falkowski, Rutgers professor of marine science and lead author of a paper published Sept. 30 in the journal Science.

Falkowskiand his colleagues have measured the abundance of carbon 13, abyproduct of photosynthesis, in deep-sea core samples that go back 205million years. Because photosynthesis produces oxygen and leaves carbon13 behind, the presence of carbon 13 in the fossil samples allowsscientists to estimate precisely how much oxygen was in the atmosphereat any given time, Falkowski says.

From a steady 10 percent – thelevel at which dinosaurs flourished – the oxygen percentage rose to 17percent 50 million years ago and then to 23 percent by 40 million yearsago.

"In the fossil record, we see that see that this rise inoxygen content corresponds exactly to a really rapid rise of large,placental mammals," Falkowski says. "The more oxygen, the bigger themammals. We argue that the rise in oxygen content allowed mammals tobecome very, very large – mammals like 12-foot-tall sloths and hugesaber-toothed cats. They paved the way for all subsequent largemammals, including ourselves."

The results described inFalkowski's article, "The Rise of Oxygen Over the Past 205 MillionYears and the Evolution of Large Placental Mammals," stem from years ofanalysis of organic and inorganic core samples. Scientists have beenusing deep-sea core samples for years, but Falkowski and his colleagueshave achieved greater precision in their measurements, thanks to twohigh-precision, isotope ratio mass spectrometers housed in thegeological sciences department at Rutgers.

There were placentalmammals on Earth at the time of the great extinction of dinosaurs about65 million years ago, Falkowski says. They were, however, tiny, limitedcreatures; the extinction event itself, while eliminating thedinosaurs, did little to further the mammalian domination of theplanet. It was the subsequent spreading of shallow seas, the increasein plant life – and photosynthesis – in addition to the consequentincrease in oxygen content that gave the mammals the boost they needed,according to Falkowski.

In the last 10 million years, thepercentage of oxygen in the earth's atmosphere has decreased to 21percent. Falkowski says many scientists believed that great firesburned over the earth about 10 million years ago, reducing the numberof trees and, therefore, the amount of photosynthesis and oxygen.


Story Source:

The above story is based on materials provided by Rutgers, the State University of New Jersey. Note: Materials may be edited for content and length.


Cite This Page:

Rutgers, the State University of New Jersey. "Oxygen Increase Caused Mammals To Triumph, Researchers Say." ScienceDaily. ScienceDaily, 3 October 2005. <www.sciencedaily.com/releases/2005/10/051003080102.htm>.
Rutgers, the State University of New Jersey. (2005, October 3). Oxygen Increase Caused Mammals To Triumph, Researchers Say. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2005/10/051003080102.htm
Rutgers, the State University of New Jersey. "Oxygen Increase Caused Mammals To Triumph, Researchers Say." ScienceDaily. www.sciencedaily.com/releases/2005/10/051003080102.htm (accessed October 22, 2014).

Share This



More Fossils & Ruins News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Sunken WWII U-Boat That Fired On U.S. Convoy Found

Sunken WWII U-Boat That Fired On U.S. Convoy Found

Newsy (Oct. 22, 2014) U-576, a long-lost German U-boat the U.S. sank in 1942, has been found just 30 miles off North Carolina's coast and near the wreckage of another ship. Video provided by Newsy
Powered by NewsLook.com
Turns Out Jack The Ripper's True Identity Is Still Unknown

Turns Out Jack The Ripper's True Identity Is Still Unknown

Newsy (Oct. 20, 2014) After testing DNA from a shawl found near one of Jack the Ripper's victims, a scientist said he'd identified the killer. New reports refute the claim. Video provided by Newsy
Powered by NewsLook.com
Fish Fossil Shows First-Ever Sex Was Done Side By Side

Fish Fossil Shows First-Ever Sex Was Done Side By Side

Newsy (Oct. 19, 2014) A 380-million-year-old fish may be the first creature to have copulative sex - and it was side by side with arms linked, like square dancers. Video provided by Newsy
Powered by NewsLook.com
As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

Newsy (Oct. 19, 2014) With Sweden on the look-out for a suspected Russian sub, a lot of people are talking about the Cold War, but is it an apt comparison? Video provided by Newsy
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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