HOME >> BIOLOGY >> NEWS
No need to thank dinosaur-killing asteroid for mammalian success

Athens, Ga. -- It is a natural history tale that every third grader knows: The dinosaurs ruled the Earth for hundreds of millions of years, until an asteroid struck the Yucatan Peninsula and triggered a mass extinction that allowed the ancestors of todays mammals to thrive.

The asteroid part of the story may still hold true, but a new study published in the March 29 issue of the journal Nature challenges the prominent hypothesis that a mass extinction of dinosaurs 65 million years ago played a major role in the diversification of todays mammals.

An international team of scientists including University of Georgia Institute of Ecology Director John Gittleman has constructed a complete evolutionary tree for mammals that puts the major diversification well after asteroid strike, casting into doubt the role the dinosaur die-off played in the success of mammals.

"The previous evidence showed that we did see a die-off of the dinosaurs and an increase in the rise of the mammals roughly 65 million years ago," Gittleman said. "But the fossil record, by its very nature, is patchy. We have found that when you fuse all of the molecular trees with the fossil evidence, the timing does not work. The preponderance of mammals really didnt take off until 10 to 15 million years after the demise of the dinosaurs."

Molecular evolutionary trees are constructed by comparing the DNA of species. Because genetic changes occur at a relatively constant rate, like the ticking of a clock, scientists can estimate the time the species diverged from their common ancestor by counting the number of mutations. Using radiocarbon dating, scientists can also estimate divergence times from the fossil record. Gittleman and his colleagues combined more than 2,500 partial trees constructed using molecular data and the fossil record to create the first virtually complete mammalian tree.

"The end result is that the mammals we know today are actually quite ol
'"/>

Contact: Sam Fahmy
sfahmy@uga.edu
706-542-5361
University of Georgia
28-Mar-2007


Page: 1 2 3

Related biology news :

1. Madagascan tropical forests return thanks to better management and well-defined ownership
2. Human proteins evolving slowly thanks to multitasking genes
3. An artificial cornea is in sight, thanks to biomimetic hydrogels
4. Pregnant drivers, football players safer thanks to a top Virginia Tech researcher
5. Producing flu vaccines will be faster and cheaper, thanks to MSU technology
6. Diabetes research takes wing thanks to long-lived fruit fly
7. Free access to world-class biological databases for European science thanks to FELICS
8. Give thanks for the cranberry, say dental researchers
9. No blind mice, thanks to UF scientists
10. New evidence indicates biggest extinction wasnt caused by asteroid or comet
11. In a first, Einstein scientists discover the dynamics of transcription in living mammalian cells

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/22/2017)... , March 21, 2017 Vigilant Solutions ... serving law enforcement agencies, announced today the appointment of ... director of public safety business development. Mr. ... enforcement experience, including a focus on the aviation transportation ... most recent position, Mr. Sheridan served as the Aviation ...
(Date:3/16/2017)... HANOVER, Germany , March 16, 2017 CeBIT 2017 - Against ... Continue Reading ... Used combined in one project, multi-biometric solutions ... ... Identification Systems) ...
(Date:3/9/2017)... and MOUNTAIN VIEW, Calif. , ... Well Made Simple," and 23andMe , the leading ... better food choices.  Zipongo can now provide customers with ... preferences, health goals and biometrics, but also genetic markers ... choices. Zipongo,s personalized food decision support platform ...
Breaking Biology News(10 mins):
(Date:3/27/2017)... Va. , March 27, 2017  Perthera,s Chief ... Cancer Center, Subha Madhavan , Ph.D., will be ... Joint Summits Panels. On Monday, March 27, 2017, she ... Oncology Data More Usable for Research and Care" (from ... March 28, 2017, she will be a participant in ...
(Date:3/27/2017)... , March 27, 2017 DarioHealth Corp. ... mobile health and big data solutions, today announced that ... insurance coverage option for U.S. consumers who want to ... DarioHealth has signed strategic alliance agreements with partners ... insurance coverage benefits, and if approved, will supply and ...
(Date:3/24/2017)... 24, 2017 Sinovac Biotech Ltd. ("Sinovac" or the "Company") ... China , today announced that its board of directors has ... the plan from March 27, 2017 to March 27, 2018. The amendment ... About Sinovac Biotech Ltd. ... Sinovac Biotech Ltd. is a China ...
(Date:3/23/2017)... ... 2017 , ... Lajollacooks4u is proud to announce it has become the premiere team-building cooking event ... companies around the world, such as Illumina, HP and Qualcomm, and is ranked #1 in ... popularity is due to its new team building format, a way for teams to not ...
Breaking Biology Technology:
Cached News: