The study, “Phylogenetic analyses reveal unexpected patterns in the evolution of reproductive modes in frogs,” led by John J. Wiens, an Associate Professor in the Department of Ecology and Evolution at Stony Brook University, and colleagues Ivan Gomez-Mestra from the Doñana Biological Station in Seville, Spain, and R. Alexander Pyron from George Washington University, uncovers the surprising evolution of life cycles in frogs.
Roughly half of all frog species have a life cycle that starts with eggs laid in water, which hatch into aquatic tadpoles, and then go through metamorphosis and become adult frogs. The other half, according to the authors, “includes an incredible diversity of life cycles, including species in which eggs are placed on leaves, in nests made of foam, and even in the throat, stomach, or back of the female frog. There are also hundreds of species with no tadpole stage at all, a reproductive mode called direct development.”
For decades, it has been assumed that the typical mode (with eggs and tadpoles placed in water) gave rise to direct development through a series of gradual intermediate steps involving eggs laid in various places outside water. “However, the results show that in many cases, species with eggs and tadpoles placed in water seem to give rise directly to species with direct development, without going through the many seemingly intermediate steps that were previously thought to be necessary,” Dr. Wiens said.
“The results also suggests that there many potential benefits for species that have retained aquatic eggs and tadpoles, such as allowing females to have more offspring and to colonize regions with cooler and drier climates. These advantages may explain why the typical frog life cycle has been maintained for more than 220 million years among thousands of species,” said Professor Wiens.
Professor Wiens | Newswise Science News
Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences
Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences