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 Waste in the water – New purification techniques for healthier aquatic ecosystems
24.07.2018 | Eberhard Karls Universität Tübingen

nachricht Plenty of habitat for bears in Europe
24.07.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

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: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Unraveling the nature of 'whistlers' from space in the lab

15.08.2018 | Physics and Astronomy

Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide

15.08.2018 | Earth Sciences

Early opaque universe linked to galaxy scarcity

15.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>