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
University of Georgia

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:

(Date:11/4/2015)... York , November 4, 2015 ... a new market report published by Transparency Market Research "Home ... Growth, Trends and Forecast 2015 - 2022", the global home ... US$ 30.3 bn by 2022. The market is estimated ... forecast period from 2015 to 2022. Rising security needs ...
(Date:10/29/2015)... 29, 2015  The J. Craig Venter Institute (JCVI) ... Synthesis and Biosecurity: Lessons Learned and Options for the ... and Human Services guidance for synthetic biology providers has ... --> --> Synthetic biology ... potential to pose unique biosecurity threats. It now is ...
(Date:10/29/2015)... BOSTON , Oct. 29, 2015  Connected health ... phenomena driving the explosion of technology-enabled health and wellness, ... his new book, The Internet of Healthy ... apps, sensors or smartphones even existed, Dr. Kvedar, vice ... model of health care delivery, moving care from the ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... Dec. 1, 2015  An interventional radiology technique shows promise ... preliminary results of a study being presented today at the ... America (RSNA). --> ... decades by interventional radiologists as a way to stop bleeding ... as a means of treating obesity is new. ...
(Date:11/30/2015)... /PRNewswire/ - Zenith Epigenetics Corp. ("Zenith" or the "Company") today ... to its Board of Directors to replace Dr. ... wealth of experience as co-founder of Resverlogix, with expertise in ... --> --> Dr. Wong remarked, "I am ... Zenith,s long standing expertise in epigenetics and the advanced stage ...
(Date:11/30/2015)... TapImmune, Inc. (TPIV), a ... peptide and gene-based immunotherapeutics and vaccines for the treatment ... be presenting at the 8 th Annual LD ... PM PT. Dr. John N. Bonfiglio a ... the presentation and will join TapImmune management in meeting ...
(Date:11/30/2015)...  Northwest Biotherapeutics (NASDAQ: NWBO ) ("NW Bio"), ... for solid tumor cancers, announced today that the Board ... the Company welcomes Neil Woodford,s call for ... internet report on NW Bio.  The Company,s Board is ... stated, "We agree with Mr. Woodford that, at ...
Breaking Biology Technology:
Cached News: