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:
TAG: need thank dinosaur killing asteroid for mammalian success

(Date:7/9/2015)... , July 9, 2015  Synaptics Inc. (NASDAQ: ... announced today that it will report financial results for ... July 30, 2015 after the close of market. The ... and investors at 2:00 p.m. PT (5:00 p.m. ET), ... To participate on the live call, analysts and ...
(Date:7/8/2015)... YORK , July 8, 2015  BD (Becton, ... BD & Guidepoint Mentor, a new program ... Guidepoint,s expert network services. BD is ... to improve healthcare delivery and outcomes and, with the ... entrepreneur will be able to directly engage with industry ...
(Date:7/7/2015)... Inc. (NASDAQ: NXTD ) ("NXT-ID" or the "Company") a biometric ... revised version of one of its first 30 second commercials will ... New York , Chicago , ... metro areas.    , , , , ... the cards in your wallet and keep your identity secure. ...
Breaking Biology News(10 mins):Synaptics to Report Fourth Quarter, Fiscal Year 2015 Results on July 30 2BD and Guidepoint Team to Connect Healthcare Start-up Companies With Business and Scientific Experts 2BD and Guidepoint Team to Connect Healthcare Start-up Companies With Business and Scientific Experts 3Wocket Smart Wallet Commercials Airing on CNBC to Showcase This Summer's Must- Have Tech Product 2Wocket Smart Wallet Commercials Airing on CNBC to Showcase This Summer's Must- Have Tech Product 3
(Date:7/29/2015)... Inc. (NYSE: BIOA ) today announced that ... resigned.  The Company has hired Andrew Ashworth , ... 2014, as full time interim CFO and has launched ... Andy Ashworth began his employment today, to overlap ... was the Company,s CFO from September 2011 to December ...
(Date:7/29/2015)... July 29, 2015 ... the addition of the "Global Biosimilars Market, ... The Global Biosimilars Market, 2015 - ... rapidly growing biosimilars market. With the blockbuster biologics ... minimize costs, biosimilars are being viewed as viable ...
(Date:7/29/2015)... 2015  Pfenex Inc. (NYSE MKT: PFNX) announced today ... released on Thursday, August 13, 2015, before the open ... will host a conference call to discuss the financial ... outlining the financial results and business update will be ... call 1-866-376-8058 (US) or 1-412-542-4131 (international) and reference Pfenex ...
(Date:7/29/2015)... , July 29, 2015 /PRNewswire/ - Aeterna Zentaris Inc. ... it has selected an optimized Erk inhibitor molecule ... the development of a new class of potential ... represents a prime target for therapeutic intervention in ... and survival benefits for B-Raf and Mek inhibitors. ...
Breaking Biology Technology:BioAmber Announces Change in Chief Financial Officer 2BioAmber Announces Change in Chief Financial Officer 3Global Biosimilars Market to 2025: Monoclonal Antibodies (mAbs), Insulin, Interferons, G-CSF/ GM-CSF, Erythropoietins and Others 2Global Biosimilars Market to 2025: Monoclonal Antibodies (mAbs), Insulin, Interferons, G-CSF/ GM-CSF, Erythropoietins and Others 3Pfenex To Report Second Quarter 2015 Results and Provide Business Update on Thursday, August 13, 2015 2Aeterna Zentaris Announces Optimized Erk Inhibitor Compounds For Further Development 2Aeterna Zentaris Announces Optimized Erk Inhibitor Compounds For Further Development 3
Cached News: