Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Early Land Animals Could Walk and Run Like Mammals

10.03.2006


Salamanders and the tuatara, a lizard-like animal that has lived on Earth for 225 million years, were the first vertebrates to walk and run on land, according to a recent study by Ohio University researchers.



After studying the creatures at the Toledo Zoo, Stephen Reilly, associate professor of biological sciences, and doctoral student Eric McElroy determined that they use both forms of locomotion, which are energy-saving mechanisms generally believed to be important only in fast-running animals such as mammals and birds.

The research was published in the March 8 issue of the journal Proceedings of the Royal Society B: Biological Sciences. Andrew Odum, curator of herpetology at the Toledo Zoo, and Valerie Hornyak, head herpetology keeper, were co-authors of the study.


Tuataras, which are usually about 1 to 2 feet long, look like large lizards with green or brown scales and short spikes on their backs. They have unique anatomical features that are somewhere between those of lizards and birds. The critters are found only in New Zealand, where the cool climate is ideal for these animals that can’t survive in temperatures above 25 degrees Celsius (77 degrees Fahrenheit). The animals can grow as old as 100 years, and live mostly off of insects, eggs and small birds. Fossil records show that the tuatara lived on Earth as early as 225 million years ago and hasn’t changed significantly over time.

“Tuataras are the oldest living models of early tetrapods (four-legged animals) still alive today; that’s what makes them so interesting,” Reilly said.

In the recent study, the tuataras and salamanders walked and ran on a trackway with an integrated plate that measured the force with which the animals hit the ground with each step. From videotapes and the force measurements, the researchers could tell when the animals were walking or running. The difference is not obvious in these critters, which tend to move with a slow, lumbering gait. That’s led scientists to believe that the primitive animals could only walk.

But force data used to study the movement of these creatures’ center of mass showed otherwise. In walking, the center of mass vaults up and over the limbs with each step. In running, the center of mass dips with each step, and tendons and joints in the legs act as biological springs. Mammals such as humans, dogs and horses can use both mechanisms to conserve up to 50 percent of their energy needed to walk and run.

When studying salamanders and tuataras, the researchers spotted the telltale vault and dip of center of mass movements in different strides – confirmation that the creatures mechanically walk and run. Because they are the oldest living examples of four-legged animals, the new findings suggest that both energy saving mechanisms appeared when the first vertebrates moved onto land, Reilly explained. In comparison to previous research on other vertebrates, this also suggests that all terrestrial vertebrates – except for turtles, which are limited by their shell – can walk and run.

The researchers also showed, however, that walking and running in tuataras occur at the same speed and use about the same amounts of energy. Reilly believes that this could be a pre-adaptation in these primitive animals that have not evolved the need for speed, unlike other animals.

The research, which was funded by the National Science Foundation and the Research Challenge Program at Ohio University, also shows for the first time a clear difference in locomotor mechanics between “lumbering” animals with clumsy, ungraceful gaits and “cursorial” animals that move fast and smoothly. In lumbering animals, up and down movements dominate the mechanical energy of locomotion. These movements are smoothed out in cursorial animals such as in dogs and horses, where more energy is shifted to forward movement, and the center of mass oscillates relatively less with each step.

Reilly and McElroy were interested in tuataras not only because they are a “living fossil,” but also because tuataras are a threatened species, according to the World Conservation Union.

“Tuataras only survive on a few small islands off New Zealand, and I would really like to study their locomotor behavior in the wild,” Reilly said. “Given their status as the world’s oldest known living tetrapod, knowing more about how these animals move in nature is critical to our understanding of vertebrate evolution.”

Andrea Gibson | EurekAlert!
Further information:
http://www.ohio.edu

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>