Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What Triggers Mass Extinctions? Study Shows How Invasive Species Stop New Life

03.01.2011
Collapse of Earth's marine life 378 to 375 million years ago holds key

An influx of invasive species can stop the dominant natural process of new species formation and trigger mass extinction events, according to research results published today in the journal PLoS ONE.

The study of the collapse of Earth's marine life 378 to 375 million years ago suggests that the planet's current ecosystems, which are struggling with biodiversity loss, could meet a similar fate.

Although Earth has experienced five major mass extinction events, the environmental crash during the Late Devonian was unlike any other in the planet's history.

The actual number of extinctions wasn't higher than the natural rate of species loss, but very few new species arose.

"We refer to the Late Devonian as a mass extinction, but it was actually a biodiversity crisis," said Alycia Stigall, a scientist at Ohio University and author of the PLoS ONE paper.

"This research significantly contributes to our understanding of species invasions from a deep-time perspective," said Lisa Boush, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.&

"The knowledge is critical to determining the cause and extent of mass extinctions through time, especially the five biggest biodiversity crises in the history of life on Earth. It provides an important perspective on our current biodiversity crises."

The research suggests that the typical method by which new species originate--vicariance--was absent during this ancient phase of Earth's history, and could be to blame for the mass extinction.

Vicariance occurs when a population becomes geographically divided by a natural, long-term event, such as the formation of a mountain range or a new river channel, and evolves into different species.

New species also can originate through dispersal, which occurs when a subset of a population moves to a new location.

In a departure from previous studies, Stigall used phylogenetic analysis, which draws on an understanding of the tree of evolutionary relationships to examine how individual speciation events occurred.

She focused on one bivalve, Leptodesma (Leiopteria), and two brachiopods, Floweria and Schizophoria (Schizophoria), as well as a predatory crustacean, Archaeostraca.

These small, shelled marine animals were some of the most common inhabitants of the Late Devonian oceans, which had the most extensive reef system in Earth's history.

The seas teemed with huge predatory fish such as Dunkleosteus, and smaller life forms such as trilobites and crinoids (sea lilies).

The first forests and terrestrial ecosystems appeared during this time; amphibians began to walk on land.

As sea levels rose and the continents closed in to form connected land masses, however, some species gained access to environments they hadn't inhabited before.

The hardiest of these invasive species that could thrive on a variety of food sources and in new climates became dominant, wiping out more locally adapted species.

The invasive species were so prolific at this time that it became difficult for many new species to arise.

"The main mode of speciation that occurs in the geological record is shut down during the Devonian," said Stigall. "It just stops in its tracks."

Of the species Stigall studied, most lost substantial diversity during the Late Devonian, and one, Floweria, became extinct.

The entire marine ecosystem suffered a major collapse. Reef-forming corals were decimated and reefs did not appear on Earth again for 100 million years.

The giant fishes, trilobites, sponges and brachiopods also declined dramatically, while organisms on land had much higher survival rates.

The study is relevant for the current biodiversity crisis, Stigall said, as human activity has introduced a high number of invasive species into new ecosystems.

In addition, the modern extinction rate exceeds the rate of ancient extinction events, including the event that wiped out the dinosaurs 65 million years ago.

"Even if you can stop habitat loss, the fact that we've moved all these invasive species around the planet will take a long time to recover from because the high level of invasions has suppressed the speciation rate substantially," Stigall said.

Maintaining Earth's ecosystems, she suggests, would be helped by focusing efforts and resources on protection of new species generation.

"The more we know about this process," Stigall said, "the more we will understand how to best preserve biodiversity."

The research was also funded by the American Chemical Society and Ohio University.

Media Contacts
Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov
Andrea Gibson, Ohio University (740) 597-2166 gibsona@ohio.edu
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2010, its budget is about $6.9 billion. NSF funds reach all 50 states through grants to nearly 2,000 universities and institutions. Each year, NSF receives over 45,000 competitive requests for funding, and makes over 11,500 new funding awards. NSF also awards over $400 million in professional and service contracts yearly.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

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: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>