Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why are some groups of animals so diverse?

21.09.2007
Cornell researchers take a look at Australia's most diverse vertebrates: skinks

A new study of finger-sized Australian lizards sheds light on one of the most striking yet largely unexplained patterns in nature: why is it that some groups of animals have evolved into hundreds, even thousands of species, while other groups include only a few?

The study takes a look at Australia’s most diverse group of vertebrates—more than 252 species of lizards called skinks. Researchers at the Cornell Lab of Ornithology have found evidence that the “drying up” of Australia over the past 20 million years triggered this explosive diversification. The results were published in the September 19 online edition of the Proceedings of the Royal Society B.

Lead author Dan Rabosky, a Cornell graduate student, spent many months in the remote Australian outback, trapping skinks as they skittered from one prickly clump of grass to another. By documenting where the various skink species occur and using their DNA to define their evolutionary tree, he found that the groups with the most species are the ones that live in the driest parts of Australia. “There’s something about colonizing the desert that caused these skinks to diversify at an incredibly high rate,” says Rabosky.

An unusual finding of this study is that these skinks upend the usual pattern of species diversity found in other parts of the world. “We typically think of lush tropical rainforests as being the world’s major centers of diversity,” says coauthor Irby Lovette, director of the Cornell Lab of Ornithology’s Fuller Evolutionary Biology Program. “With the skinks, just the opposite has happened: the rainforest skinks in Australia have much lower diversity, and a lot of the evolutionary ‘action’ in this system is taking place in the deserts.”

Over the last 20 million years, most of Australia changed from humid and tropical to bone-dry desert. “Living in the desert is stressful for animals that are adapted for wetter habitats,” says Rabosky. “But somewhere in the distant past, a few skinks developed the ability to survive in their increasingly arid world.” It is the descendents of these few early desert colonists that evolved into amazingly large numbers of skink species.

“Australian skinks are really fascinating,” Rabosky says. “Two groups in particular have gone evolutionarily crazy, each splitting into as many as 100 different species. In contrast to skinks on other continents, and even some other groups in Australia, the diversity of these particular groups has really exploded.”

Rabosky’s study included skinks with spots, skinks with stripes, skinks with four legs, or two—or none. Rabosky says there are at least 252 species of these lizards living Down Under, and probably many more that remain to be discovered.

The evolution of these skinks mirrors that of many groups of organisms—from grasses, to beetles, to humans and our relatives—in which some groups have spectacular diversity and others a paucity of species. “For me as a scientist,” says Rabosky, “one of the great things about skinks is that there are just so darn many species, making the patterns in their diversity really clear.”

Miyoko Chu | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Studies and Analyses:

nachricht Real-time feedback helps save energy and water
08.02.2017 | Otto-Friedrich-Universität Bamberg

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>