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 Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

nachricht Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>