Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Broken arms and collateral damage: clues to predator-driven evolution

06.09.2004


Ever since Darwin’s day, scientists have been trying to understand how interactions among living creatures---competition and predation, for example---drive evolution.



Recent work by paleontologists Tomasz Baumiller of the University of Michigan and Forest Gahn of the Smithsonian’s National Museum of Natural History offers new insights into the process. A report on their research appears in today’s issue of Science.

Biologists long have speculated that predators and prey play a game of evolutionary one-upsmanship, in which an adaptation on the part of one---say, sharper teeth in a predator---prompts a "go-you-one-better" response in the other---tougher hide in the prey, for instance. Hints that this has occurred are scattered throughout the fossil record, but not evenly, Baumiller said. During one part of the Paleozoic Era known as the Middle Paleozoic Marine Revolution, for example, the diversity of shell-crushing predators increased explosively. Around the same time, some 380 million years ago, mollusks and other shell-bearing marine animals developed better protective devices, such as more spines or more tightly-coiled shells.


Apparently, the prevalence of shell-crushers prompted development of better defenses against them. But simply finding evidence of changes in both predators and prey doesn’t prove that one caused the other, Baumiller noted. "You have to provide evidence that they, in fact, were interacting."

To search for such evidence, Baumiller and his former graduate student Gahn, studied fossil crinoids, a group of marine animals related to starfish and sea urchins. Crinoids, also called sea lilies, have feathery arms that they extend to catch bits of plankton or detritus passing by in the current.

Like their starfish cousins and other animals in the group known as echinoderms, crinoids are capable of regenerating lost body parts. Because modern day crinoids usually lose---and regenerate---their arms as a result of attacks by fish, Baumiller and Gahn reasoned that arm regeneration in fossil crinoids would be a good indicator of predator-prey interactions in the geologic past.

To test their idea, they examined more than 2,500 Paleozoic crinoids for evidence of arm regeneration, focusing on fossils from the Ordovician to Pennsylvanian Periods (490 to 290 million years ago). As predicted, they found that the only significant increase in regeneration frequency was during the Middle Paleozoic Marine Revolution. "Indeed, the frequency of regeneration, which we regard as a proxy for predation intensity, was low during intervals before the Middle Paleozoic Marine Revolution and then there was a sudden increase, coincident with the diversification of predators and the increase in the evolutionary response of the prey," Baumiller said.

That’s not the whole story, though. Baumiller and Gahn suspect that crinoids were not the intended targets of the predators that inflicted damage upon them, and that their broken arms were simply "collateral damage." Crinoids, Baumiller explained, play host to a variety of other organisms that take up residence on various parts of their bodies, and the predators were probably going after those creatures.

One way to test this notion would be to look for correlations between the degree of infestation and the rate of regeneration, and Baumiller, Gahn and Carlton Brett, a paleontologist from the University of Cincinnati, have applied for funding to do just that.

Nancy Ross-Flanigan | EurekAlert!
Further information:
http://www.umich.edu

More articles from Health and Medicine:

nachricht Organ-on-a-chip mimics heart's biomechanical properties
23.02.2017 | Vanderbilt University

nachricht Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München

All articles from Health and Medicine >>>

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

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>