Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Darwin’s ugly duckling surprises evolutionary biologists

03.06.2015

Speciation and hybridization in Galápagos-marine iguanas

Charles Darwin had a very clear opinion of Galápagos marine iguanas - “a hideous-looking creature, of a dirty black colour, stupid and sluggish in its movements”. However, Darwin’s ‘ugly duckling’ has surprised a research team of evolutionary biologists from the Technische Universität Braunschweig.


No ugly at all - marine iguanas are fascinating inhabitants of the Galápagos islands and the only sea going lizard world-wide

U Braunschweig/Alejandro Ibáñez Ricomá


Coming a long way - a red migrant marine iguana from Española on San Cristóbal island

TU Braunschweig/Amy MacLeod

Their results show, for the first time, the speciation of two populations of marine iguanas occurring on the same small island – a phenomenon that is even unknown for much smaller lizards. This research sheds new light on the fascinating and complex evolutionary processes of the Galápagos archipelago.

Although at a first glance these dragon-like creatures appear aesthetically challenged, marine iguanas are among the most fascinating organisms of the Galápagos Islands. They are the only sea going lizards world-wide, foraging in the marine environment and have colonized all major and smaller islands of the archipelago. However, from a scientific perspective, their evolution remains poorly understood when compared to that of Darwin’s finches or the giant Galápagos tortoises.

New insights into the evolution of marine iguanas now shift them into the focus of modern evolutionary research. An international research team, led by Dr. Sebastian Steinfartz from the Zoological Institute of the Technische Universität Braunschweig, has shown for the the first time that speciation of these large and mobile reptiles can occur on an unusual small scale.

In a new research paper, published in Proceedings of the Royal Society B, the team show that reproductive isolation, the beginning of species formation or ‘speciation’, of marine iguana populations has developed on the small island of San Cristóbal within a very short period of time in the absence of spatial barriers. Speciation on such a small spatial scale was until now unknown, even from much smaller lizards.

“We were surprised to find evidence for almost complete reproductive isolation between the two groups” remembers PhD student Amy MacLeod, who sampled hundreds of these prehistoric-looking reptiles during several trips to the Galápagos. At the same time, the team also found that reproduction between migrants from other islands, a kind of hybridisation, was surprisingly common.

Indeed, the system seems to be far more complex than initially thought, and allows for intriguing insights into the evolutionary processes of the Galápagos. “We are witnessing a never-before documented situation in the animal kingdom, where speciation is directly paralleled by hybridization” Sebastian Steinfartz explains. Although both groups of marine iguanas avoid breeding with each other, and therefore behave as distinct species on the island, they both interbreed and hybridize with migrant marine iguanas from nearby islands freely. As a result, the speciation process remains incomplete, and over evolutionary time-scales of several million of years, marine iguanas seemingly appear to be a single species, Steinfartz points out.

The scientists hypothesize that by the direct interaction of these opposing evolutionary forces, namely speciation and hybridization, the potential of marine iguanas to adapt to changing environmental conditions in the Galápagos archipelago is enhanced. This may have enabled them to persist for millions of years. “Perhaps this mechanism is the key to understanding the success of marine iguanas in surviving for such a long time on the archipelago despite the dynamic conditions” Steinfartz argues.

Local adaptations, resulting from speciation might be absorbed by recurrent hybridization into a common species gene pool. This could enable the marine iguana to rapidly adapt and persist over the long-term, despite repeatedly suffering from severe population crashes driven by climatic fluctuations such as El Niño events. The team expect further surprises from this fascinating organism. “I hope that the ugly duckling now grows up and will develop into a white swan allowing us deeper insights into evolutionary processes in the future” says Steinfartz with a smile.

Publication
MacLeod A, Rodriguez A, Vences M, Orozco-terWengel P, Garcia C, Trillmich F, Gentile G, Caccone A, Quezada G, Steinfartz S. Hybridization masks speciation in the evolutionary history of the Galápagos Marine Iguana. Proceedings oft he Royal Society B (http://dx.doi.org/10.1098/rspb.2015.0425 )[Platzhalter]

Contact

Dr. Sebastian Steinfartz
Zoological Institute
Evolutionary biology
Technische Universität Braunschweig
Mendelssohnstraße 4
38106 Braunschweig
Tel.: +49 531/391-2393
E-Mail: s.steinfartz@tu-braunschweig.de
www.zoologie.tu-bs.de/index.php/en/evolutionsbiologie

Weitere Informationen:

http://blogs.tu-braunschweig.de/presseinformationen/?p=8988

Stephan Nachtigall | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Equipping form with function

23.06.2017 | Information Technology

New design improves performance of flexible wearable electronics

23.06.2017 | Materials Sciences

Individualized fiber components for the world market

23.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>