Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

When animals evolve on islands, size doesn’t matter

07.11.2007
A theory explaining the evolution of giant rodents, miniature elephants, and even miniature humans on islands has been called into questions by new research published today in Proceedings of the Royal Society B: Biological Sciences.

The new study refutes the ‘island rule’ which says that in island environments small mammals such as rodents tend to evolve to be larger, and large mammals such as elephants tend to evolve to be smaller, with the original size of the species being the key determining factor in these changes.

The new research findings suggest that the tendency to either evolve larger or smaller on islands varies from one group of species to another, irrespective of original size. The research team, from Imperial College London, suspect instead that a number of external factors, including the physical environment of the particular island, the availability of prey, the presence of predators and the presence of competing species all play a role in determining the size evolution of island mammals.

Dr Shai Meiri from the NERC Centre for Population Biology at Imperial College London, lead author on the paper, explains: “If the island rule was correct, then most large mammals living on islands would be smaller than their continental relatives, and most small island mammals would be larger those living on continents. Our large dataset of mammal body sizes shows that this isn’t the case: there is evidence that most mammal groups show no tendency to consistently either grow larger or smaller, in contradiction to the island rule.”

... more about:
»Evolution »Island »evolve »mammal »size

Dr Meiri, who carried out the work with Professor Andy Purvis and Natalie Cooper from the College’s Department of Life Sciences, added: “The island rule suggests that the smallest mammals such as mice will exhibit the most evolutionary growth on islands, whilst the largest mammals like elephants will dwarf the most, with all mammals in between on a sliding-scale.

“Our analyses showed this isn’t the case, and the relationship between mammal size and evolutionary size change on islands is not that straightforward. Crucially, when we examined size change in light of the evolutionary relationship between different species, there was no connection between an evolution towards large size and greater degree of dwarfism on islands, or between evolution towards small size and island gigantism.”

The research team concluded that although there does appear to be a weak correlation between the size of a mammal and how its size then evolves in an island habitat, this reflects some groups’ specific tendencies towards gigantism or dwarfism, and not the general course of evolution. “The course of size evolution is dependent on a complex interplay of many other factors, that have led to the evolution of fascinating miniature and giant species of mammals on islands,” concludes Dr Meiri.

Danielle Reeves | alfa
Further information:
http://www.imperial.ac.uk

Further reports about: Evolution Island evolve mammal size

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | 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

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>