Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

An (ecological) origin of species for tropical reef fish

06.04.2005



Dealing a new blow to the dominant evolutionary paradigm, Luiz Rocha and colleagues from the Smithsonian Tropical Research Institute, Harvard University the University of Florida and the University of Hawaii, report coral reef fish from neighboring habitats may differ more from one another than from fish thousands of miles away. An ecological speciation model for coral reef organisms may spur the development of a more synthetic treatment of speciation on land and sea.

Coral reefs, like tropical forests, express an extreme of life’s capacity for variation. Yet high biodiversity in tropical seas foil evolutionists’ attempts to explain the splitting of one species into two on the basis of geographical barriers. According to standard evolutionary theory proposed by Dobzhansky and Mayr more than 50 years ago, mountain building, island formation, glaciation and other processes isolate populations within a species. Over evolutionary time, these populations mutate independently until individuals from distinct populations can no longer interbreed and become new species.

What explains the evolution of a huge number of closely related fish species on reefs in an open undersea world where currents constantly stir the waters, washing in fish or their larvae from afar, a world without well-defined geographical barriers? Rocha et al. took a close look at the genetics of one group of Western Atlantic tropical reef fishes (wrasses, genus Halichoeres) throughout their range and were surprised by what they found.



Rocha explains: "I was interested in the Amazon barrier. The Amazon and Orinoco’s freshwater and sediment discharge off of northeastern South America is so immense that it precludes coral reef formation from the mouth of the Amazon North to Trinidad and Tabago. This 2000 km gap is believed to be a strong barrier for corals and associated reef organisms."

"My idea was to test whether or not wrasses in the genus Halichoeres were genetically different North and South of this barrier. Since all of these species have similar abilities to disperse, I expected to find genetic differences that corresponded to the barrier in all of them, but, surprisingly, that wasn’t the case."

Mitochondrial DNA of adult fish and larvae from three locations in the Caribbean and from three locations in Brazil showed much clearer genetic differences within, rather than across, the two sides of the Amazon barrier. Genetically similar fish were found in ecologically similar habitats--even thousands of miles apart.

Wrasses collected only 360 km apart along the Brazilian coast were genetically more distinct than were fish collected 4200 km apart, from Fernando de Noronha island off of the Brazilian coast and St. Croix in the Caribbean.

The fact that evolutionary partitions correspond more closely to habitat type, rather than to conventional geographical barriers, indicates that local speciation events may overcome the homogenizing effect of migration in the ocean, vindicating Darwin’s original ideas about the importance of ecological speciation in biodiversity evolution.

Beth King | EurekAlert!
Further information:
http://www.si.edu
http://www.luizrocha.com/gallery9.htm
http://www.stri.org

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

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 >>>