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El Esmalte dental podría tener su Origen en las Escamas de los Peces

El esmalte que recubre nuestros dientes es el mismo que compartimos con otras especies de animales tetrápodos y peces. Ahora, un nuevo hallazgo revela que el origen de este material dental se encuentra en peces ya extintos. 
Catán pinto o pejelagarto ocelado (Lepisosteus oculatus)
Científicos de Suecia y China han combinado datos genéticos y fósiles para demostrar que la ganoína, presente en peces extintos o primitivos como el Catán pinto o pejelagarto ocelado (Lepisosteus oculatus), es similar al esmalte dental. El estudio, publicado en la revista Nature, sugiere que el

Ginandromorfos: Extraños animales mitad Macho y mitad Hembra

Sus cuerpos están divididos en dos, por la mitad. Ellos podrían ayudarnos a entender cómo se desarrolla el sexo

También en langostas se ha identificado el fenómeno.

En el lado derecho, el pollo del doctor H. E. Schaef parecía un gallo joven cualquiera, con una cresta roja y papada. Pero viendo el lado izquierdo, pensarías que era una gallina: su cuerpo era más delgado y tenía marcas más lisas.
Su comportamiento era, además, muy confuso. La criatura intentaba montar a las otras gallinas, pero también ponía unos pequeños huevos.

Hoy, estas criaturas se conocen como "ginandromorfos bilaterales". Al contrario que los hermafroditas, cuya inversión de género empieza y acaba en los genitales, estos animales están divididos por todo su cuerpo: machos de un lado, hembras del otro.

La soledad del ginandromorfo
Hace varios cientos de siglos que se avistaron estos animales

Ancient ecosystem response to 'big five' mass extinction (Respuesta de antiguo Ecosistema a la mayor extinción masiva, la Pérmico-Triasica)

Artículo en Español y en Inglés
(Spanish & English article)

A Late Permian scene features one of that period's famed extinction survivors, Lystrosaurus. Scene by Marlene Hill Donnelly.
Credit: Copyright California Academy of Sciences and Marlene Hill Donnelly

English article
Ingenious modeling shows that the stability of ancient ecosystems depended on species with important, big-picture roles in food web

As the planet faces the dawn of a sixth mass extinction, scientists are searching for clues about the uncertain road ahead by exploring how ancient ecosystems collapsed and bounced back from traumatic upheavals. 

Plot of extinction intensity (percentage of genera that are present in each interval of time but do not exist in the following interval) vs time in the past for marine genera.Geological periods are annotated (by abbreviation and colour) above. The Permian–Triassic extinction event is the most significant event for marine genera, with just over 50% (according to this source) failing to survive.
A new study follows the lengthy collapses and revival of South African ecosystems during one of the "big five" mass extinctions, the Permian-Triassic event, revealing unexpected results about the types of animals that were most vulnerable to extinction, and the factors that might best predict community stability during times of great change. 

The study's authors--including Peter Roopnarine, PhD, of the California Academy of Sciences--say inventive, cutting-edge modeling techniques helped highlight the critical importance of understanding food webs (knowing "who eats what") when trying to predict what communities look like before, during, and after a mass extinction. The thought-provoking study is the first of its kind, and is published today in Science.

"Vital clues" in deep time
"There is no real precedent for what's happening to our planet at the moment," says Roopnarine, who co-authored the study with Kenneth Angielczyk, PhD, of Chicago's Field Museum

As Curator of Geology, Roopnarine is accustomed to thinking in "deep time"--a geologic reference to the vast, multimillion-year timeframe some scientists use to unravel mysteries from Earth's pre-human existence. Past extinctions and climate perturbations may lack the human factors driving today's phenomena, but Roopnarine says those periods "contain vital clues" about the ways natural communities respond to crises and rebuild.

Modeling ancient extinctions

Roopnarine and Angielczyk were interested in the factors that encouraged or impeded stability while these ancient South African communities faced large-scale disturbances. They wondered whether the roles each species played in the broader ecosystem had more influence on stability than species richness--the number of different species in a system-- and the number and strength of interactions among species. The scientists decided to use a clever form of mathematical modeling to dig into the importance of these variables in (sometimes spotty) fossil food webs.

After generating several alternate food webs for each important period, the scientists examined each to see how stable they might have been. Results were surprising.

"We saw that, after disturbing a pre-extinction community and all of its alternate models, the real community always emerged as the most stable," says Roopnarine. "Since we held species richness constant, we know that each species' ecological roles--the jobs in the food web--are the key factors influencing big-picture stability. It's amazing that some of these ecosystems may have remained relatively stable despite huge biodiversity loss."

"A bad time to be a rat"
Aside from the glaring absence of human influence, mass extinctions during the Permian still looked quite different than the ecological upheaval we see on Earth today. Modern conservation efforts tend to center around large animals--such as tigers, elephants, and wolves--and top predators in peril, while Roopnarine and Angielczyk show that small amniotes (reptiles and ancient mammal relatives) were most vulnerable during the early phase of this long-ago period of extinction.

"It's surprising that small amniotes were the species initially most at-risk," says Roopnarine. "It doesn't fit with the terrestrial extinctions we see today, but it makes sense when you think about how different Earth looks after so much time and change."

"What I'm saying," Roopnarine adds, "is that it was a bad time to be a rat. We think they can survive anything now, but during the Permian and Triassic, their ancient cousins played an unlucky role in the larger community. The food webs at the time could remain stable if they were dominated by large amniotes and lacked smaller ones, but not the other way around. Though individually successful, collectively the smaller species could not support very stable communities. Over time, the quality of a single business matters less than the quality of the overall economy."

Food webs as conservation tools
Every line in an intricate food web represents powerful ecosystem interactions and exchanges of energy. Clues from past systems that recovered or failed following disasters help scientists peer into the future of the ever-changing natural world. This study's results are an urgent call for an increased focus on modern food webs--an area of research Roopnarine says needs increased attention in a time of unprecedented environmental stress.

"We need to understand the relationships between the species we're driving to extinction, and the roles they play in ecosystem stability," says Roopnarine. "We know the collapse of Atlantic cod wreaked havoc on marine ecosystems, but we know very little about the ways most species' ecologies relate to stability. It can be surprising which species help hold ecosystems together. We desperately need more data for the modern environment."

Roopnarine says museum collections, including the Academy's nearly 46 million specimens, are powerful tools in the race to understand what helps an environment remain stable. When applied to scientific specimens, new technologies and advanced techniques help uncover the complex relationships inherent in biodiverse--and threatened--regions worldwide.
Source: Sciencedaily

Artículo en Español

Lycaenops, un gorgonopsio, grupo que desapareció en la Gran Extinción Pérmica-Triasica.

Ingenioso modelo demuestra que la estabilidad de los ecosistemas antiguos dependía de las especies con roles importantes en las redes alimentarias

A medida que el planeta se enfrenta a los albores de la sexta extinción en masa, los científicos están buscando pistas sobre un futuro incierto explorando cómo los ecosistemas antiguos

Raw: Thirsty Leopard Jams Head into Pot (VIDEO)

A leopard got its head stuck in a metal pot after venturing into a village in northern India on Wednesday. Media reports said it was thirsty and tried to drink water. Eventually, it was tranquilized, freed and released into the wild. (Sept. 30) Video provided by AP

Deep-diving whales spark inspiration for synthetic blood (Buceo de profundidad de las Ballenas podría inspirar la creación de Sangre sintética)

Artículo en Español y en Inglés
(Spanish & English article)

English article
Deep-diving whales may harbor the key to synthetic blood development for trauma patients, R&D Magazine reports. Researchers at Rice University in Houston, Texas, published work in The Journal of Biological Chemistry comparing the oxygen carrying proteins of whales, humans, and other deep-diving mammals and found that the whales have an ultrastable version, allowing them to stay submerged for long periods of time. Researchers hope that a whale-inspired oxygen carrier could help develop synthetic blood in the future.

Artículo en Español
El buceo de gran profundidad de las Ballenas puede albergar la clave del desarrollo de la sangre sintética para los pacientes de trauma, informa R & D Magazine . Investigadores de la Universidad de Rice en Houston, Texas, publicaron trabajos en The Journal of Biological Chemistry comparando a las proteinas transportadoras de oxígeno de las ballenas, los seres humanos y otros mamíferos de inmersión profunda. Encontraron que las ballenas tienen una versión ultra estable, lo que les permite permanecer sumergidas por largos períodos de tiempo. Los investigadores esperan que un transportador de oxígeno inspirado en el de las ballenas podría ayudar a desarrollar sangre sintética en el futuro.