(Press-News.org) Birds that are related, such as Darwin's finches, but that vary in beak size and behavior specially evolved to their habitat are examples of a process called speciation. It has long been thought that dramatic changes in a landscape like the formation of the Andes Mountain range or the Amazon River is the main driver that initiates species to diverge. However, a recent study shows that speciation occurred much later than these dramatic geographical changes. Researchers from LSU's Museum of Natural Science have found that time and a species' ability to move play greater parts in the process of speciation. This research was published today in the print edition of Nature.
"The extraordinary diversity of birds in South America is usually attributed to big changes in the landscape over geological time, but our study suggests that prolonged periods of landscape stability are more important," said Robb Brumfield, LSU Museum of Natural Science director and Roy Paul Daniels professor in the Department of Biological Sciences, one of the lead authors.
Brumfield and his colleagues examined the genealogy of 27 species of birds in the most bio-diverse region in the world, the Neotropics, which extends from southern Mexico through Central America to southern Brazil and includes the Amazon rainforest.
"By using detailed sampling of many bird lineages, we were able to get a clearer and larger picture of when and how species formed within those lineages," Brumfield said.
The genetic data showed multiple accounts of species divergence, from nine to 29 different instances across the Andes Mountains that varied over time. This shows that rather than being the primary cause of speciation, the formation of the Andes Mountains had an indirect effect on diversification as a semi-permeable barrier.
The researchers then investigated how the history and ecology affected speciation among the 27 lineages of birds. They discovered the longer length of time a species can inhabit an area, the more likely it will disperse and diverge. Also, the less mobility a species has, the more likely it will diverge as well. For example, birds restricted to the forest floor showed significantly higher species diversity than birds that inhabited the forest's open canopy. These findings have conservation ramifications. If a species cannot inhabit the same area for an extended time, it will not have the opportunity to evolve and continue.
"Our results suggest that human alterations of the landscape can effectively kill the speciation process," Brumfield said.
INFORMATION:
This research was funded by the National Science Foundation. Other institutions involved in this research include the American Museum of Natural History, City College of New York, Museu Paraense Emílio Goeldi in Brazil, Universidad de los Andes in Colombia, Universidad Central de Venezuela, Colección Ornithológica Phelps, University of California Los Angeles and the University of Georgia Athens.
The thousands of samples used in this study represent the culmination of more than 30 years of field expeditions led by generations of LSU students and scientists, plus similar work done by ornithologists at other research institutions.
The mission of the LSU Museum of Natural Science is the acquisition, preservation and study of research collections by museum faculty, staff and students to generate knowledge of regional and global biodiversity, geological history and human history/prehistory for the benefit of the people of Louisiana, the nation and the world. For more information on the museum, visit http://www.museum.lsu.edu/. Follow the museum's Twitter, @LSU_MNS. Like the museum's LSU Big Day Peru Facebook for updates as the international award-winning birding team prepares to break the world Big Day record, http://www.facebook.com/LSUBigDay.
The mission of the Department of Biological Sciences is to create and disseminate new knowledge in the biological sciences through research; to provide for its majors the highest quality, nationally recognized, graduate and undergraduate educational programs; to provide exceptional science training to support the university's general education requirements; and to contribute expertise in support of science education in the community, including the use of available resources to improve K-12 science outreach. For more information, visit http://www.biology.lsu.edu/.
The higher your level of education, the greater your earnings and your sense of "personal mastery" or being in control of your fate, University of Toronto researchers say. But wait: there's a downside.
Professor Scott Schieman, Canada Research Chair in the Social Contexts of Health, and PhD student Atsushi Narisada investigated the adverse effects associated with attaining a high degree of mastery. Using the Canadian Work, Stress, and Health Study (CANWSH), a national sample of Canadian workers, the researchers measured proficiency, or mastery, by asking study participants ...
Thanks to the NASA/ESA Hubble Space Telescope, some of the most mysterious cosmic residents have just become even more puzzling. New observations of globular clusters in a small galaxy show they are very similar to those found in the Milky Way, and so must have formed in a similar way. One of the leading theories on how these clusters form predicts that globular clusters should only be found nestled in among large quantities of old stars. But these old stars, though rife in the Milky Way, are not present in this small galaxy, and so, the mystery deepens.
Globular clusters ...
Modern hand dryers are much worse than paper towels when it comes to spreading germs, according to new University of Leeds research.
Scientists from the University of Leeds have found that high-powered 'jet-air' and warm air hand dryers can spread bacteria in public toilets. Airborne germ counts were 27 times higher around jet air dryers in comparison with the air around paper towel dispensers.
The study shows that both jet and warm air hand dryers spread bacteria into the air and onto users and those nearby.
The research team, led by Professor Mark Wilcox of the ...
PharmaMar results for antitumoral compounds and their mechanism of action at EORTC-NCI-AACR emphasize an innovative pipeline of targeted therapies
Targeting of eEF1A2 by antitumor drug Aplidin® reveals novel mechanism of action driving therapeutic efficacy
A newly developed antibody-drug conjugate (ADC) combining a marine-derived agent with trastuzumab shows potent antitumoral activity in breast tumors overexpressing HER2 grown in mice
Antitumoral activity of investigational drugs with different molecular targets in the pipeline highlights their potential ...
Almost one third of male adolescents inaccurately perceive their weight. This can influence their eating habits and, consequently, their health, according to a study led by the UAB and conducted with 600 teenage boys from Barcelona and surrounding areas. Up to 25% of the boys reported trying to lose or control their weight in the past year.
The research, conducted in collaboration with the Mental Health Unit of the Parc Taulí Health Corporation (CSPT), analysed the effects weight perception had on the boys' behaviour when trying to lose or maintain their weight. ...
WASHINGTON - U.S. Naval Research Laboratory (NRL) scientists, in collaboration with researchers from the University of Manchester, U.K.; Imperial College, London; University of California San Diego; and the National Institute of Material Science (NIMS), Japan, have demonstrated that confined surface phonon polaritons within hexagonal boron nitride (hBN) exhibit unique metamaterial properties that enable novel nanoscale optical devices for use in optical communications, super-resolution imaging and improved infrared cameras and detectors.
Metamaterials are artificial composites ...
Las Médulas in León is considered to be the largest opencast goldmine of the Roman Empire, but the search for this metal extended many kilometres further south-east to the Erica river valley. Thanks to a Light Detection and Ranging (LiDAR) laser system attached to an aircraft, the ancient mining works of the area and the complex hydraulics system used by the Romans in the 1st century BC to extract gold (including channels, reservoirs and a double river diversion) have been discovered.
"The volume of earth exploited is much greater than previously thought and ...
Researchers from North Carolina State University have developed a technique that allows ultrasound to penetrate bone or metal, using customized structures that offset the distortion usually caused by these so-called "aberrating layers."
"We've designed complementary metamaterials that will make it easier for medical professionals to use ultrasound for diagnostic or therapeutic applications, such as monitoring blood flow in the brain or to treat brain tumors," says Tarry Chen Shen, a Ph.D. student at NC State and lead author of a paper on the work. "This has been difficult ...
A new database developed by the University of Cantabria (Spain) provides data on sea level variation due to atmospheric changes in the south of Europe between 1948 and 2009. Over the last two decades sea levels have increased in the Mediterranean basin.
"The meteorological sea level or meteorological tide component is the variation of the sea level as a result of atmospheric changes or more specifically, changes in the atmospheric pressure and the wind at the sea surface," Alba Cid explains to SINC, Alba being the lead author of the study published in the journal 'Climate ...
Patients affected by Parkinson's disease often show marked changes in body weight: they may gain or lose a lot of weight depending on the stage of the disease, or they may put on up to ten kilos after deep brain stimulation (a treatment to alleviate the symptoms). This situation considerably worsens the quality of life of a person who is already suffering from heavily disabling motor disorders, so it is important to understand what are the factors that cause it.
"The body weight and eating habits of Parkinson's patients change as the disease progresses", explains Marilena ...
