Navigation Links
Giants among us: Paper explores evolution of the world’s largest mammals
Date:11/25/2010

Athens, Ga. The largest mammal that ever walked the earthIndricotherium transouralicum, a hornless rhinoceros-like herbivore that weighed approximately seventeen tons and stood about eighteen feet high at the shoulderlived in Eurasia almost 34

Athens, Ga. The largest mammal that ever walked the earthIndricotherium transouralicum, a hornless rhinoceros-like herbivore that weighed approximately seventeen tons and stood about eighteen feet high at the shoulderlived in Eurasia almost 34 million years ago. In a paper just published in the journal Science, an international team of researchers has compiled and analyzed an enormous database of information about the largest mammals across time and around the globe, revealing striking patterns in their evolution.

The research, funded by a National Science Foundation Research Coordination Network grant, was led by scientists at the University of New Mexico, who brought together paleontologists, evolutionary biologists and macroecologists from universities around the world. University of Georgia Odum School of Ecology dean John Gittleman and postdoctoral researcher Patrick Stephens were among them.

"We were invited to participate because the group wanted to take an explicitly evolutionary approach to size," said Gittleman, whose research focuses on large-scale ecological and evolutionary problems, from disease to extinction to organism characteristics.

"John and Patrick were indispensable members of our team," said Felisa Smith, associate professor of biology at the University of New Mexico and the paper's lead author. "This really was a project that took all of us to accomplish."

The goal of the research was to revisit key questions about size, specifically in mammals. "Size impacts everything, from reproduction to extinction," said Gittleman. "And mammals are a good test case. There is so much variationeverything from mice to elephantsand there is also far more data available about mammals than other taxonomic groups."

"There is a much better fossil record for mammals than for many other groups," Stephens said. "That's partly because mammals' teeth preserve really well. And as it happens, tooth size correlates well with overall body size."

The researchers spent two years assembling the data. "The database is powerful and unique," said Gittleman. "It includes information on the size of all mammals, living and fossil, from around the world."

With access to so much information, the group was able to test a hypothesis about the evolution of mammal size.

"During the Mesozoic, mammals were small," said Gittleman. "Once dinosaurs went extinct, mammals evolved to be much larger as they diversified to fill ecological niches that became available. This phenomenon has been well-documented for North America; we wanted to know if the same thing happened all over the world."

The researchers found that the pattern was indeed consistent, not only globally but across time and across trophic groups and lineagesthat is, animals with differing diets and descended from different ancestorsas well. The maximum size of mammals began to increase sharply about 65 million years ago, peaking in the Oligocene Epoch (about 34 million years ago) in Eurasia, and again in the Miocene Epoch (about 10 million years ago) in Eurasia and Africa.

"Having so many different lineages independently evolve to such similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals across the globe," said Gittleman. "The consistency of the pattern strongly implies that biota in all regions were responding to the same ecological constraints."

Global temperature and the amount of land available as an animal's range are two ecological factors that appear to correlate with the evolution of maximum body size, but Gittleman warned against assigning cause and effect. "A big part of science is seeing patterns, and then producing new hypotheses and testing them," he said. "We have now identified this pattern very rigorously."


'/>"/>

Contact: John Gittleman
ecohead@uga.edu
706-542-2968
University of Georgia
Source:Eurekalert

Related biology news :

1. Canopy giants and miniature fungi among 250 new species discovered in Kews 250th anniversary year
2. Overweight primarily a problem among wealthier women in low- to middle-income countries
3. Social support post-cancer lacking among minority women
4. Father absence linked to earlier puberty among certain girls
5. Immune responses during pregnancy linked to schizophrenia among offspring
6. The fungus among us: A new way of decomposing BPA-containing plastic
7. Scientific expertise lacking among doubters of climate change, says Stanford-led analysis
8. Fungus among us could become non-food source for biodiesel production
9. UM School of Medicine study finds vaginal microbes vary among healthy women
10. LSU identifies community conditions related to malnutrition deaths among older adults
11. Home medication errors common among children with chronic conditions
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/3/2016)... , March 3, 2016  FlexTech, a SEMI ... categories of Innovation, Research & Development, Leadership in Education, ... This is the 9 th year of the ... of companies and individuals from past years . ... on a pre-described set of criteria, by a panel ...
(Date:3/2/2016)... 2016 http://www.researchandmarkets.com/research/wzwqtz/global_biometrics ... the  "Global Biometrics Market in Hospitality Sector ... http://photos.prnewswire.com/prnh/20130307/600769) , , Global biometrics market in ... CAGR of around 27%   --> ... the addition of the  "Global Biometrics Market ...
(Date:3/1/2016)... FRANCISCO , March 1, 2016  (RSAC Booth ... year, but a whopping $118 billion is lost to ... to overzealous and inaccurate fraud detection. At the RSA ... in the way companies handle authentication by devaluing the ... and behavioral analytics. --> ...
Breaking Biology News(10 mins):
(Date:4/27/2016)... New York, NY (PRWEB) , ... April 27, ... ... without realizing it. Touch screen mobile devices with fingerprint recognition for secure ... image libraries are only a few ways consumers are interacting with biometrics technology ...
(Date:4/27/2016)... RESEARCH TRIANGLE PARK, N.C. , April ... UTHR ) announced today that Martine Rothblatt , ... will provide an overview and update on the company,s ... Health Care Conference. The presentation will take ... Eastern Time, and can be accessed via a live ...
(Date:4/27/2016)... ... April 27, 2016 , ... ... has joined the company as an Expert Consultant. Mr. Clark was formerly ... and managing the development of small molecule monographs based on analytical methods. ...
(Date:4/27/2016)... ... April 27, 2016 , ... ... PET (Positron Emission Tomography) and MRI (Magnetic Resonance Imaging) in existing third-party MRI ... testing novel treatments in small animal subjects. Simultaneous PET/MRI imaging offers a solution ...
Breaking Biology Technology: