Navigation Links
Oxygen increase caused mammals to triumph, researchers say

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.

Falkowski and his colleagues have measured the abundance of carbon 13, a byproduct of photosynthesis, in deep-sea core samples that go back 205 million years. Because photosynthesis produces oxygen and leaves carbon 13 behind, the presence of carbon 13 in the fossil samples allows scientists to estimate precisely how much oxygen was in the atmosphere at any given time, Falkowski says.

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

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

The results described in Falkowski's article, "The Rise of Oxygen Over the Past 205 Million Years and the Evolution of Large Placental Mammals," stem from years of analysis of organic and inorganic core samples. Scientists have been using deep-sea core samples for years, but Falkowski and his colleagues have achieved greater precision in their measurements, thanks to two high-precision, isotope ratio mass spectrometers housed in the geological sciences department at Rutgers.

There were placental mammals on Earth at the time of the great extinction of dinosaurs about 65 million years ago, Falko wski says. They were, however, tiny, limited creatures; the extinction event itself, while eliminating the dinosaurs, did little to further the mammalian domination of the planet. It was the subsequent spreading of shallow seas, the increase in plant life - and photosynthesis - in addition to the consequent increase in oxygen content that gave the mammals the boost they needed, according to Falkowski.

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


'"/>

Source:Rutgers, the State University of New Jersey


Related biology news :

1. Plant hemoglobins: Oxygen handlers critical for nitrogen fixation
2. Yeast Network Prevents Damage By Oxygen Radicals
3. Boosting HIV screening can increase survival and is cost effective
4. Sexual cooperation: Mating increases longevity in ant queens
5. Mother birds increase progesterone to hatch females
6. Ibruprofen and other commonly used painkillers for treating inflammation may increase the risk of heart attack
7. Global warming increases oyster sensitivity to pollution
8. Prescription pain patch abuse blamed for increase in deaths
9. Prenatal exposure to famine increases risk of schizophrenia
10. Agricultural workers at increased risk for infection with animal flu viruses
11. Gene increases risk of tuberculosis
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/15/2016)... , March 15, 2016 ... report published by Transparency Market Research "Digital Door Lock Systems ... Forecast 2015 - 2023," the global digital door lock systems ... Mn in 2014 and is forecast to grow at a ... of micro, small and medium enterprises (MSMEs) across the world ...
(Date:3/11/2016)... , March 11, 2016 http://www.apimages.com ) ... Cross reference: Picture is available at AP Images ( http://www.apimages.com ) ... DERMALOG will be used to produce the new refugee identity cards. ... biometric innovations, at CeBIT in Hanover next ... from DERMALOG will be used to produce the new refugee identity ...
(Date:3/9/2016)... , March 9, 2016 This BCC Research ... states of the RNA Sequencing (RNA Seq) market for ... as instruments, tools and reagents, data analysis, and services. ... segments of the RNA-Sequencing market such as RNA-Sequencing tools ... the main factors affecting each segment and forecast their ...
Breaking Biology News(10 mins):
(Date:4/27/2016)... ... , ... The Pittcon Organizing Committee is pleased to announce that Charles “Chuck” ... of Committee since 1987. Since then, he has served in a number of key ... for both the program and exposition committees. In his professional career, Dr. Gardner is ...
(Date:4/27/2016)... ... April 27, 2016 , ... The Board of ... appointment of John Tilton as Chief Commercial Officer.  Mr. Tilton joined Biohaven from ... founding commercial leaders responsible for the commercialization of multiple orphan drug indications. ...
(Date:4/27/2016)... (PRWEB) , ... April 27, 2016 , ... Global ... the GSCG Advisory Board. Ross is the founder of GSCG affiliate Kimera Labs in ... Miami, where he studied hematopoietic stem cell transplantation for hematologic disorders and the suppression ...
(Date:4/26/2016)... ANGELES, Calif. (PRWEB) , ... April 27, 2016 ... ... Angeles office of Lewis Roca Rothgerber Christie LLP as an associate in the ... prosecuting U.S. and international electrical, mechanical and electromechanical patent applications. He has an ...
Breaking Biology Technology: