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:8/14/2019)... ... , ... Join Jonathan Riek, PhD, VP, Musculoskeletal & Metabolic Imaging, BioTel ... 1pm EDT to learn about two common imaging methods in NAFLD/NASH to aid with ... common diffuse liver disease, with a worldwide prevalence of 20-46 percent. NAFLD can be ...
(Date:8/9/2019)... ... August 09, 2019 , ... With a demand in healthcare to lower unneeded ... visit urgent care centers (UCC) in the coming years, according to a new report ... for Urgent Care Centers , is a detailed look at the current state of ...
(Date:8/6/2019)... ... August 06, 2019 , ... The demand ... plant-based food in particular quickly entered the limelight – meat alternatives. Yet, to ... thermogelling and emulsifying ingredient such as methyl cellulose. This ingredient is highly synthetic. ...
Breaking Biology News(10 mins):
(Date:6/11/2019)... ... June 10, 2019 , ... ... add 80 of its scientific journals to DeepDyve’s rental service for peer-reviewed journals. ... continually expanding library of more than 20 million articles, sourced from more than ...
(Date:6/11/2019)... ... 2019 , ... Veterinary Regenerative Medicine company, VetStem Biopharma ... that their GMP facility for cell production is now approved by the California ... an important milestone for VetStem as it expands into contract cell manufacturing services. ...
(Date:6/6/2019)... ... 05, 2019 , ... WCCT Global, Inc ., a full-service early phase ... they will be receiving 3 awards at the 2019 CRO Leadership Awards, to be ... the categories of overall Quality and Compatibility (Access to desired markets, cultural fit, timely ...
(Date:5/31/2019)... ... May 29, 2019 , ... ... providing proprietary interest to our methodology, processes, and diagnostic techniques. The patent ... extends Somnology’s IP rights including our proprietary sleep scoring methodology. The approval ...
Breaking Biology Technology:
Cached News: