Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recreating ancient vertebrate's first step on dry land

11.07.2016

Researchers use robot, mathematical models and studies of amphibious fish to explore critical evolutionary leap

Could a tail have allowed ancient vertebrates to make the transition from water to land?


Image shows the 'MuddyBot' robot that uses the locomotion principles of the mudskipper to move through a trackway filled with granular materials. The robot has two limbs and a powerful tail, with motion provided by electric motors.

Credit: Rob Felt, Georgia Tech

Reporting in Science today, researchers from Georgia Institute of Technology, Carnegie Mellon University, Clemson University and National Institute for Mathematical and Biological Synthesis described results of a groundbreaking study to answer this question using amphibious fish, a custom-built robot and mathematical models of movement.

The study tested the hypothesis that coordinated tail movement played an important role in evolution of terrestrial vertebrates. The researchers found that, for the first critical step out of an aqueous environment and onto a riverbank or mudflat, stabilizing the body with a tail provided substantial benefits.

... more about:
»NSF »amphibious fish »living organisms

The effort, supported by the National Science Foundation (NSF), the Army Research Office and the Army Research Laboratory, brought together experts in physics, biology, robotics and mathematics who explored the question through a variety of experimental methods.

Daniel Goldman, an associate professor in the Georgia Tech School of Physics and the principal investigator on the NSF award that supported the work, says he has long been obsessed with the question of how the first creatures moved onto land.

"I was interested in evolutionary biology from a natural history perspective: imagining the grand scope of life on Earth and trying to understand how animals lived hundreds of millions of years ago and in this case, trying to understand how major transitions in behavior happened." Goldman says. "For me this has been a nice integration of my interests applied to a question which I just think is fascinating: what did the earliest animals do when they were trying to crawl around on land?"

To answer the question, he and his collaborators took a three-pronged approach.

First, they explored the behavior and body mechanics of the African mudskipper -- an amphibious fish that lives in tidal areas near shore and uses its front fins and tail to move on land with a "crutching" motion. The mudskipper is one of a handful of living organisms considered to be potentially close in body structure to the first terrestrial vertebrates.

In co-author Richard Blob's lab at Clemson University, researchers recorded the movements of mudskippers in an environment akin to riverbanks where early land-dwellers may have emerged to see how they behaved.

"We found when mudskippers are using their tail on a sufficiently inclined sandy slope they do pretty well and when they don't, they don't do well," Goldman concluded.

Next, the researchers developed a simplified, mudskipper-like version of a robot, which they call "MuddyBot," on which they could systematically vary the angle and movements of the robot's flipper-like limbs and tail. They used MuddyBot to find out which coordinated motions of limb and tail were most effective on granular surfaces of different inclines. They call this approach "robophysics" -- a novel way to understanding the behavior of long-lost species.

Finally, they used a mathematical and engineering method called "geometric mechanics" (developed in the 1980s by physicist and Nobel Prize winner Frank Wilczek and his student Alfred Shapere) to analyze all the possible ways the MuddyBot can move in space and on different surfaces. This helps determine what types of movement may or may not have allowed the creature to pull itself up onto a sandy or muddy slope. This process also involved developing a better understanding of the physics of sand and the way that a granular medium can compress or slip when something tries to move on it.

The variety of approaches provided the teams with quantitative evidence to support the idea that the first locomotors may have had tails and may have used a crutching motion to move out of the water.

"Insight from these experiments led us to hypothesize that propulsive use of the tail, an appendage that has received relatively little attention in previous studies of the invasion of land, may have been the critical adaptation that allowed these early walkers to gain ground on challenging substrates," says Benjamin McInroe, a co-author on the paper and then an Georgia Tech undergraduate (now a Ph.D. student at the University of California, Berkeley) who analyzed the mudskipper data provided by the Clemson team.

"Professor Goldman and his collaborators are combining physics and engineering prototyping approaches to understand the physical principles that allow animals to move in different environments," says Krastan Blagoev, program director in the NSF Division of Physics. "This novel approach to living organisms promises to bring to biological sciences higher predictive power and at the same time uncover engineering principles that we have never imagined before."

The team's well-documented and analytic-rich findings only chart the critical first step out of the aqueous environment and not the full progression up a riverbank and onto level ground. After that first step, things get even more complicated because sand flows in a way that scientists don't yet have the physics to describe.

"Even this ridiculously seemingly simple little crutching motion with coordinated tail use confronts our ignorance in three or four different disciplines: biology, paleontology, robotics, and mathematics," says Goldman. "That's a summary of how far away we are from really understanding it."

Instead of being discouraged by this fact, the realization motivates Goldman.

"That's the great joy in all this," he says. "Just looking at these simple problems, there's a huge amount of insight to be had from applying new tools."

The research provides a rigorous approach to studying evolutionary questions in the future by combining animal, robotic and mathematical approaches. It even may improve designs for robots that can move on sand or loose dirt and help in search and rescue missions - a focus of Howie Choset's work at Carnegie Mellon University.

"Our computer modeling tools allow us to visualize, and therefore better understand, how the mudskipper incorporates its tail and flipper motions to locomote," says Howie Choset, a professor in the Robotics Institute at Carnegie Mellon University. "This work also will advance robotics in those cases where a robot needs to surmount challenging terrains with various inclinations."

It is impossible to say for sure yet if the earliest locomotors used a crutching behavior like the mudskipper, Goldman says. For that reason, the team is now making robots to test some alternative possibilities, including robots with bodies like salamanders that move with a diagonal gait.

"It really is exciting to imagine that some of these models that we're cooking up in the lab in these relatively simple robots could have anything to say about something that happened 360 million years ago," he says, "and to be able to demonstrate that these questions, which seem so simple on first blush, actually require deep insights into the fundamentals of all sorts of disciplines including physics, biology and robotics."

Media Contact

Aaron Dubrow
adubrow@nsf.gov
703-292-4489

 @NSF

http://www.nsf.gov 

Aaron Dubrow | EurekAlert!

Further reports about: NSF amphibious fish living organisms

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>