PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Ancient connection between the Americas enhanced extreme biodiversity

Ancient connection between the Americas enhanced extreme biodiversity
2015-04-28
(Press-News.org) Species exchange between North and South America created one of the most biologically diverse regions on Earth. A new study by Smithsonian scientists and colleagues published this week in the Proceedings of the National Academy of Sciences shows that species migrations across the Isthmus of Panama began about 20 million years ago, some six times earlier than commonly assumed. These biological results corroborate advances in geology, rejecting the long-held assumption that the Isthmus is only about 3 million years old.

"Even organisms that need very specific conditions to survive, such as salamanders and freshwater fishes, crossed the Isthmus of Panama over 6 million years ago," said lead author, Christine Bacon, former post-doctoral fellow in staff scientist Carlos Jaramillo's group at the Smithsonian Tropical Research Institute. "These early migrations impact our understanding of how and when biodiversity in the Americas took shape."

The Isthmus of Panama, which links North and South America, plays a crucial role in the planet's atmospheric and oceanic circulation, climate and biodiversity. Despite its importance across multiple disciplines, the timing of the formation and emergence of the Isthmus and the effect it had on those continents' biodiversity is controversial.

In the new study, Bacon, now at the University of Gothenburg in Sweden, examines a large number of molecular studies and fossils, including land and aquatic organisms.

Models based on molecular genetic data indicate that rather than one great migration following a set closure time, there were several periods in which animals and plants moved across the intercontinental land bridge. There are shifts in the rate of movement of animal fossils moving from North America to South America at 23 million and within the past 10 million years.

Authors also compare the proportion of immigrants in each direction to sea level and global mean temperature, showing that migrations may have coincided with low sea levels.

A known date for the rise of the Isthmus is important to evolutionary biologists who want to understand how species of marine organisms diverged and when species of terrestrial organisms moved from one continent to another. The date is also critical in understanding ancient climate change patterns. The 3 million year date was established by the Panama Paleontology Project, headed by Jeremy Jackson and Anthony Coates, also at the Smithsonian Tropical Research Institute.

INFORMATION:

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a part of the Smithsonian Institution. The institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website: http://www.stri.si.edu Bacon, C.D., D. Silvestro, C.A. Jaramillo, B. Tilston Smith, P. Chakrabarty, A. Antonelli. Biological evidence shows earlier emergence of the Isthmus of Panama. Accepted, Proceedings of the National Academy of Sciences USA. doi:10.1073/pnas.1423853112


[Attachments] See images for this press release:
Ancient connection between the Americas enhanced extreme biodiversity

ELSE PRESS RELEASES FROM THIS DATE:

As circumcision wounds heal, HIV-positive men may spread virus to female partners

2015-04-28
In the midst of an international campaign to slow the spread of HIV in sub-Saharan Africa, the World Health Organization recommends male circumcision (the surgical removal of foreskin from the penis) which reduces HIV acquisition by 50-60%. However, scientists report that a new study of HIV-infected men in Uganda has identified a temporary, but potentially troublesome unintended consequence of the procedure: a possible increased risk of infecting female sexual partners while circumcision wounds heal. In a study by researchers from the Johns Hopkins University School ...

Diverse sea creatures evolved to reach same swimming solution

2015-04-28
The ability to move one's body rapidly through water is a key to existence for many species on this blue planet of ours. The Persian carpet flatworm, the cuttlefish and the black ghost knifefish look nothing like each other - their last common ancestor lived 550 million years ago, before the Cambrian period - but a new study uses a combination of computer simulations, a robotic fish and video footage of real fish to show that all three aquatic creatures have evolved to swim with elongated fins using the same mechanical motion that optimizes their speed, helping to ensure ...

Wound healing, viral suppression linked to less HIV shedding from circumcision wounds

2015-04-28
The likelihood of viral shedding from male circumcision wounds intially increases, then decreases as the wounds heal, and is lower in patients with lower plasma viral load, according to a study published this week in PLOS Medicine. The study, conducted by Aaron Tobian, of Johns Hopkins University, Baltimore, MD and the Rakai Health Sciences Program, Entebbe, Uganda, and colleagues, monitored 223 HIV-infected men for wound healing and viral shedding from their surgical wounds for 12 weeks following voluntary medical male circumcision. The researchers found that, compared ...

No single cut-off for parasite half-life can define artemisinin-resistant malaria

2015-04-28
Data from southeast Asia -- where artemisinin-resistant malaria strains were first detected -- broadly support WHO's 'working definition' for artemisinin resistance, but the currently used definitions require important refinements, according to a study by Lisa White and colleagues, from Mahidol University in Bangkok, Thailand, published this week in PLOS Medicine. The drug artemisinin rapidly clears malaria parasites from the blood of infected patients -- unless the parasites have developed resistance, in which case parasite clearance after artemisinin therapy (ACT) takes ...

Loyola study provides evidence that premature girls thrive more than premature boys

2015-04-28
A new study from Loyola University Medical Center provides further evidence that female infants tend to do better than males when born prematurely. The study found that female infants independently orally fed one day earlier than males. The ability to suck, swallow and breathe simultaneously are reflexes that many premature infants are unable to do. Learning to master these skills and eat independently without feeding tubes is necessary before an infant can safely go home from the hospital. Researchers set out to determine the mean age when premature infants are able ...

Not much size difference between male and female Australopithecines

Not much size difference between male and female Australopithecines
2015-04-28
Lucy and other members of the early hominid species Australopithecus afarensis probably were similar to humans in the size difference between males and females, according to researchers from Penn State and Kent State University. "Previous convention in the field was that there were high levels of dimorphism in the Australopithecus afarensis population," said Philip Reno, assistant professor of anthropology, Penn State. "Males were thought to be much larger than females." Sexual dimorphism refers to differences between males and females of a species. These can show up, ...

New study links drinking behaviors with mortality

2015-04-28
A new University of Colorado Boulder study involving some 40,000 people indicates that social and psychological problems caused by drinking generally trump physically hazardous drinking behaviors when it comes to overall mortality rates. The study showed, for instance, that participants who had experienced an intervention by physicians, family members or friends had a 67 percent greater risk of death over the 18-year study period, said sociology Professor Richard Rogers, lead study author. Those who reported cutting down on social or sports activities because of alcohol ...

Study allays concerns that cardiothoracic physicians-in-training provide suboptimal care

2015-04-28
When educating medical students or residents to perform highly technical procedures, there is always a challenge to balance the educational mission with maintaining quality results and optimal patient care. This report compared outcomes of cardiac surgery residents to those of attending physicians in performing coronary artery bypass grafting. It found no differences in patient outcomes or graft patency between the residents and attending surgeons. Seattle WA, April 28, 2015 - A conundrum in medical education is how to train residents in complex and technically difficult ...

Age at surgery and valve type in PVR key determinants of re-intervention in congenital heart disease

2015-04-28
Over the last 15 years, survival of children with congenital heart disease (CHD) has greatly improved, so that currently there are more adults than children living with CHD. Consequently, people with CHD of all ages are undergoing pulmonary valve replacement (PVR) with bioprosthetic valves. In this retrospective review of all patients with CHD who underwent bioprosthetic PVR over an 18-year period at Boston Children's Hospital, investigators found that young age and small body weight predisposed patients toward re-intervention, as did the type of valve used. Seattle, ...

Boston Children's Hospital study reveals first 6 months best for stimulating heart growth

Boston Childrens Hospital study reveals first 6 months best for stimulating heart growth
2015-04-28
Boston, Mass (April 27, 2015) -- In a recent issue of Science Translational Medicine, Brian Polizzotti, PhD, Bernhard Kuhn, MD, Sangita Choudhury, PhD, and colleagues affiliated with the Boston Children's Hospital's Translational Research Center report that the optimal window of time to stimulate heart muscle cell regeneration (cardiomyocyte proliferation) in humans is the first six months of life. "Our results suggest that early administration of neuregulin may provide a targeted and multipronged approach to prevent heart failure in infants with CHD. Beginning treatment ...

LAST 30 PRESS RELEASES:

Exercise as an anti-ageing intervention to avoid detrimental impact of mental fatigue

UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’

New guidelines aim to improve cystic fibrosis screening

Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas

Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition

CCNY physicists uncover electronic interactions mediated via spin waves

Researchers’ 3D-printing formula may transform future of foam

Nurture more important than nature for robotic hand

Drug-delivering aptamers target leukemia stem cells for one-two knockout punch

New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed

New sea grant report helps great lakes fish farmers navigate aquaculture regulations

Strain “trick” improves perovskite solar cells’ efficiency

How GPS helps older drivers stay on the roads

Estrogen and progesterone stimulate the body to make opioids

Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation

Machine learning helps construct an evolutionary timeline of bacteria

Cellular regulator of mRNA vaccine revealed... offering new therapeutic options

Animal behavioral diversity at risk in the face of declining biodiversity

Finding their way: GPS ignites independence in older adult drivers

Antibiotic resistance among key bacterial species plateaus over time

‘Some insects are declining but what’s happening to the other 99%?’

Powerful new software platform could reshape biomedical research by making data analysis more accessible

Revealing capillaries and cells in living organs with ultrasound

American College of Physicians awards $260,000 in grants to address equity challenges in obesity care

Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential

Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research

Solar cells made of moon dust could power future space exploration

Deporting immigrants may further shrink the health care workforce

Border region emergency medical services in migrant emergency care

Resident physician intentions regarding unionization

[Press-News.org] Ancient connection between the Americas enhanced extreme biodiversity