Rhino and ceratopsian dinosaurs, how big?


This 29 November 2018 video says about itself:

A walking animated rhino vs Ceratops species. Christmas is one month away lol and for that we will showcase to you this video on comparison of rhino size vs the size of ceratopsian species.

In this video, you shall see the walking animated white rhinoceros of over 6 feet in height and a list of large and small ceratopsian species shall slide one by one in ascending order of size. We included extinct Triceratops, extinct Eotriceratops, extinct Pachyrhinosaurus, and other small and large ceratopsian species.

The size of these ceratopsian species are all from mid to large estimates and so the same goes to the size comparison of the white rhinoceros (rhino) against these extinct dinosaurs.

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Permian-Triassic mass extinction by global warming


This July 2018 video says about itself:

252 million years ago 96% of all marine species and 70% of terrestrial vertebrate species vanished, this was the Permian extinction.

From the University of Washington in the USA:

Biggest mass extinction caused by global warming leaving ocean animals gasping for breath

December 6, 2018

Summary: By combining ocean models, animal metabolism and fossil records, researchers show that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe. As temperatures rose and the metabolism of marine animals sped up, the warmer waters could not hold enough oxygen for their survival.

The largest extinction in Earth’s history marked the end of the Permian period, some 252 million years ago. Long before dinosaurs, our planet was populated with plants and animals that were mostly obliterated after a series of massive volcanic eruptions in Siberia.

Fossils in ancient seafloor rocks display a thriving and diverse marine ecosystem, then a swath of corpses. Some 96 percent of marine species were wiped out during the “Great Dying”, followed by millions of years when life had to multiply and diversify once more.

What has been debated until now is exactly what made the oceans inhospitable to life — the high acidity of the water, metal and sulfide poisoning, a complete lack of oxygen, or simply higher temperatures.

New research from the University of Washington and Stanford University combines models of ocean conditions and animal metabolism with published lab data and paleoceanographic records to show that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe. As temperatures rose and the metabolism of marine animals sped up, the warmer waters could not hold enough oxygen for them to survive.

The study is published in the Dec. 7 issue of Science.

“This is the first time that we have made a mechanistic prediction about what caused the extinction that can be directly tested with the fossil record, which then allows us to make predictions about the causes of extinction in the future”, said first author Justin Penn, a UW doctoral student in oceanography.

Researchers ran a climate model with Earth’s configuration during the Permian, when the land masses were combined in the supercontinent of Pangaea. Before ongoing volcanic eruptions in Siberia created a greenhouse-gas planet, oceans had temperatures and oxygen levels similar to today’s. The researchers then raised greenhouse gases in the model to the level required to make tropical ocean temperatures at the surface some 10 degrees Celsius (20 degrees Fahrenheit) higher, matching conditions at that time.

The model reproduces the resulting dramatic changes in the oceans. Oceans lost about 80 percent of their oxygen. About half the oceans’ seafloor, mostly at deeper depths, became completely oxygen-free.

To analyze the effects on marine species, the researchers considered the varying oxygen and temperature sensitivities of 61 modern marine species — including crustaceans, fish, shellfish, corals and sharks — using published lab measurements. The tolerance of modern animals to high temperature and low oxygen is expected to be similar to Permian animals because they had evolved under similar environmental conditions. The researchers then combined the species’ traits with the paleoclimate simulations to predict the geography of the extinction.

“Very few marine organisms stayed in the same habitats they were living in — it was either flee or perish”, said second author Curtis Deutsch, a UW associate professor of oceanography.

The model shows the hardest hit were organisms most sensitive to oxygen found far from the tropics. Many species that lived in the tropics also went extinct in the model, but it predicts that high-latitude species, especially those with high oxygen demands, were nearly completely wiped out.

To test this prediction, co-authors Jonathan Payne and Erik Sperling at Stanford analyzed late-Permian fossil distributions from the Paleoceanography Database, a virtual archive of published fossil collections. The fossil record shows where species were before the extinction, and which were wiped out completely or restricted to a fraction of their former habitat.

The fossil record confirms that species far from the equator suffered most during the event.

“The signature of that kill mechanism, climate warming and oxygen loss, is this geographic pattern that’s predicted by the model and then discovered in the fossils,” Penn said. “The agreement between the two indicates this mechanism of climate warming and oxygen loss was a primary cause of the extinction.”

The study builds on previous work led by Deutsch showing that as oceans warm, marine animals’ metabolism speeds up, meaning they require more oxygen, while warmer water holds less. That earlier study shows how warmer oceans push animals away from the tropics.

The new study combines the changing ocean conditions with various animals’ metabolic needs at different temperatures. Results show that the most severe effects of oxygen deprivation are for species living near the poles.

“Since tropical organisms’ metabolisms were already adapted to fairly warm, lower-oxygen conditions, they could move away from the tropics and find the same conditions somewhere else,” Deutsch said. “But if an organism was adapted for a cold, oxygen-rich environment, then those conditions ceased to exist in the shallow oceans.”

The so-called “dead zones” that are completely devoid of oxygen were mostly below depths where species were living, and played a smaller role in the survival rates. “At the end of the day, it turned out that the size of the dead zones really doesn’t seem to be the key thing for the extinction,” Deutsch said. “We often think about anoxia, the complete lack of oxygen, as the condition you need to get widespread uninhabitability. But when you look at the tolerance for low oxygen, most organisms can be excluded from seawater at oxygen levels that aren’t anywhere close to anoxic.”

Warming leading to insufficient oxygen explains more than half of the marine diversity losses. The authors say that other changes, such as acidification or shifts in the productivity of photosynthetic organisms, likely acted as additional causes.

The situation in the late Permian — increasing greenhouse gases in the atmosphere that create warmer temperatures on Earth — is similar to today.

“Under a business-as-usual emissions scenarios, by 2100 warming in the upper ocean will have approached 20 percent of warming in the late Permian, and by the year 2300 it will reach between 35 and 50 percent,” Penn said. “This study highlights the potential for a mass extinction arising from a similar mechanism under anthropogenic climate change.”

Gecko lizards can walk on water


This video says about itself:

Geckos can run across water

Geckos (Hemidactylus platyurus) have the ability to exceed the speed limits of conventional surface swimming, running across water at up to almost a meter a second using a unique mix of surface tension and slapping.

Credits: UC Berkeley/Roxanne Makasdjian/Stephen McNally/Pauline Jennings, Jasmine A. Nirody, Judy Jinn, Thomas Libby, Timothy J. Lee, Ardian Jusufi, David L. Hu, Robert J. Full.

Music: Horses to Water by Topher Mohr and Alex Elena courtesy of YouTube Audio Library

From the University of California – Berkeley in the USA:

Acrobatic geckos, highly maneuverable on land and in the air, can also race on water

Geckos combine surface tension with foot slapping to stay above water surface

December 6, 2018

Summary: Asian geckos were observed running over water at nearly a meter per second, as fast as on land. Lab experiments show how. They get support from surface tension but also slap the water rapidly with their feet. They also semi-plane over the surface and use their tail for stabilization and propulsion. They thus sit between insects, which use only surface tension, and larger animals, which run upright via foot slapping alone.

Geckos are renowned for their acrobatic feats on land and in the air, but a new discovery that they can also run on water puts them in the superhero category, says a University of California, Berkeley, biologist.

“They can run up a wall at a meter per second, they can glide, they can right themselves in midair with a twist of their tail and rapidly invert under a leaf running at full speed. And now they can run at a meter per second over water. Nothing else can do that; geckos are superheroes,” said Robert Full, a UC Berkeley professor of integrative biology.

Full is the senior author of a paper that will appear this week in the journal Current Biology describing four separate strategies that geckos use to skitter across the surface of water. First author Jasmine Nirody, a biophysicist at the University of Oxford and Rockefeller University, conducted much of the research with Judy Jinn, both as Ph.D. students at Berkeley.

According to Full, who discovered many of the unique maneuvers and strategies geckos employ, including how their toe hairs help them climb smooth vertical surfaces and hang from the ceiling, the findings could help improve the design of robots that run on water.

Nirody first became intrigued by geckos’ water-running behavior after co-author Ardian Jusufi, now a biophysicist at Max Planck Institute for Intelligent Systems and another former UC Berkeley Ph.D. student, noticed that geckos in the forests of southeast Asia could skitter across puddles to escape predators.

In fact, they are able to run at nearly a meter, or three feet, per second over water and easily transition to speeding across solid ground or climbing up a vertical surface. Geckos sprinting on the water’s surface exceed the absolute swimming speeds of many larger, aquatic specialists including ducks, minks, muskrats, marine iguanas and juvenile alligators, and are faster in relative speed than any recorded surface swimmer, other than whirligig beetles.

How, she wondered, do they do that?

Smaller animals like insects — spiders, beetles and water striders, for example — are light enough to be kept afloat by surface tension, which allows them to easily glide across the surface. Larger animals, such as swans during takeoff or the basilisk lizard, and even dolphins rising up on their tails, rapidly slap and stroke the water to keep above the waves.

“Bigger animals can’t use surface tension, so they end up pushing and slapping the surface, which produces a force if you do it hard enough,” Full said.

But the gecko is of intermediate size: at about 6 grams (one-fifth of an ounce, or the weight of a sheet of paper), they are too large to float above the surface, but too light to keep their bodies above water by slapping forces only.

“The gecko’s size places them in an intermediate regime, a middle ground,” Nirody said. “They can’t generate enough force to run along the surface without sinking, so the fact they can race across water is really surprising.”

In experiments with flat-tailed house geckos (Hemidactylus platyurus), common in south and southeast Asia, she discovered that they actually use at least two and perhaps four distinct strategies to run atop the water surface.

Surface tension is essential, she found, because when she applied a surfactant or soap to eliminate surface tension, the geckos were much less efficient: their speed dropped by half.

Even without surface tension, however, they can move using slapping, paddling movements with their four legs like larger animals. Leg slapping created air pockets that helped keep their bodies from being completely submerged, allowing them to trot across the water in much the same way they run on land.

But they also seem to use their smooth, water-repellent skin to plane across the surface, similar to hydroplaning but referred to as semi-planing, a technique used by muskrats.

Finally, they also use their tail to swish the water like an alligator, providing propulsion as well as lift and stabilization.

“All are important to some extent, and geckos are unique in combining all these,” Full said.

“Even knowing the extensive list of locomotive capabilities that geckos have in their arsenal, we were still very surprised at the speed at which they could dart across the water’s surface,” Nirody said. “The way that they combine several modalities to perform this feat is really remarkable.”

In the lab, she and her colleagues built a long water tank, placed the geckos on a plank and startled them by touching their tails. Using high-speed video, they were able to closely study the geckos’ techniques and estimate the forces involved.

This research was funded by the National Science Foundation and the Swiss National Science Foundation. Other co-authors of the paper are Thomas Libby and Timothy Lee of UC Berkeley and David Hu from Georgia Tech.

Blue-fronted Amazon parrot genome studied


This 2015 video shows a blue-fronted parrot, Amazona aestiva, eating guaritá, Astronium graveolens, flowers in Mato Grosso do Sul in Brazil.

From Carnegie Mellon University in the USA:

Parrot genome analysis reveals insights into longevity, cognition

Genome of blue-fronted Amazon parrot compared with 30 other long-lived birds

December 6, 2018

Parrots are famously talkative, and a blue-fronted Amazon parrot named Moises — or at least its genome — is telling scientists volumes about the longevity and highly developed cognitive abilities that give parrots so much in common with humans. Perhaps someday, it will also provide clues about how parrots learn to vocalize so well.

Morgan Wirthlin, a BrainHub post-doctoral fellow in Carnegie Mellon University’s Computational Biology Department and first author of a report to appear in the Dec. 17 issue of the journal Current Biology, said she and her colleagues sequenced the genome of the blue-fronted Amazon and used it to perform the first comparative study of parrot genomes.

By comparing the blue-fronted Amazon with 30 other long- and short-lived birds — including four additional parrot species — she and colleagues at Oregon Health and Science University (OHSU), the Federal University of Rio de Janeiro and other entities identified a suite of genes previously not known to play a role in longevity that deserve further study. They also identified genes associated with longevity in fruit flies and worms.

“In many cases, this is the first time we’ve connected those genes to longevity in vertebrates,” she said.

Wirthlin, who began the study while a Ph.D. student in behavioral neuroscience at OHSU, said parrots are known to live up to 90 years in captivity — a lifespan that would be equivalent to hundreds of years for humans. The genes associated with longevity include telomerase, responsible for DNA repair of telomeres (the ends of chromosomes), which are known to shorten with age. Changes in these DNA repair genes can potentially turn cells malignant. The researchers have found evidence that changes in the DNA repair genes of long-lived birds appear to be balanced with changes in genes that control cell proliferation and cancer.

The researchers also discovered changes in gene-regulating regions of the genome — which seem to be parrot-specific — that were situated near genes associated with neural development. Those same genes are also linked with cognitive abilities in humans, suggesting that both humans and parrots evolved similar methods for developing higher cognitive abilities.

“Unfortunately, we didn’t find as many speech-related changes as I had hoped,” said Wirthlin, whose research is focused on the evolution of vocal behaviors, including speech. Animals that learn songs or speech are relatively rare — parrots, hummingbirds, songbirds, whales, dolphins, seals and bats — which makes them particularly interesting to scientists, such as Wirthlin, who hope to gain a better understanding of how humans evolved this capacity.

“If you’re just analyzing genes, you hit the end of the road pretty quickly,” she said. That’s because learned speech behaviors are thought be more of a function of gene regulation than of changes in genes themselves. Doing comparative studies of these “non-coding” regulatory regions, she added, is difficult, but she and Andreas Pfenning, assistant professor of computational biology, are working on the computational and experimental techniques that may someday reveal more of their secrets.

This work was supported through the Brazilian Avian Genome Consortium and by the National Institutes of Health/National Institute on Deafness and Other Communication Disorders.

Brazilian tree frogs parenting, new study


This June 2015 video says about itself:

7 Tiny Frogs Found on 7 Brazilian Mountains

Researchers in Brazil discovered seven never-before-seen species of Brachycephalus frog on seven different mountains in the Atlantic forest.

From PLOS:

Not too big, not too small: Tree frogs choose pools that are just right

Frogs breeding in pools of water on leaves face trade-off between drying out and repelling predators

December 5, 2018

Frogs that raise their young in tiny pools of water that collect on plant leaves must make a delicate trade-off between the risk of drying out and the risk of being eaten, according to a study publishing December 5 in the open-access journal PLOS ONE by Mirco Solé from the Universidade Estadual de Santa Cruz in Bahia, Brazil and colleagues.

The temporary pools of water trapped by the leaf rosette of some plants in the Bromeliaceae family are used by a variety of creatures as a source of prey, water and shelter — one example is the Broad-snout casque-headed Tree Frog (Aparasphenodon arapapa) which uses the water ‘tanks’ of bromeliad plants as a place to mate and rear its tadpoles. To understand how the frogs choose the right spot, the researchers measured the characteristics, including size, water level, and leaf debris, of the central tanks of 239 bromeliads in Reserve Boa União in Bahia, Brazil.

They compared bromeliads that were occupied by a tree frog with those that were empty and found that male frogs generally prefer bromeliads with larger tanks, a higher volume of water, and less leaf litter — qualities which make the tanks less likely to dry up and easier to access. However, the very largest and fullest bromeliad tanks were frog-less, suggesting that a trade-off exists when choosing the best place to breed. Males have a specially shaped bony head that they use to form a tight seal with the opening of the bromeliad tank, which is thought to protect them from predators. Forming a tight seal may be tricky in very large bromeliads, making them a poor choice as a shelter.

The authors conclude that the trade-offs animals face when selecting a site to breed should be taken into consideration in conservation strategies.

Solé adds: “Aparasphenodon arapapa, a tropical frog from the Brazilian Atlantic Forest places its eggs into bromeliads, but instead of simply choosing the largest bromeliad tank with the most water, complex trade-offs between selection pressures and balancing water requirements are involved in the bromeliad choice.”

Jurassic ichthyosaur was warm-blooded, new research


This 15 June 2018 video says about itself:

Ichthyosaurs 101 | National Geographic

Meaning “fish lizard” in Greek, the aptly-named ichthyosaur once dominated the world’s oceans for millions of years. Learn about these prehistoric marine reptiles and see how features, such as basketball-sized eyes and a vertical tail, helped the ichthyosaur secure a place at the top of the ancient food chain.

From the North Carolina State University in the USA:

Soft tissue shows Jurassic ichthyosaur was warm-blooded, had blubber and camouflage

December 5, 2018

An ancient, dolphin-like marine reptile resembles its distant relative in more than appearance, according to an international team of researchers that includes scientists from North Carolina State University and Sweden’s Lund University. Molecular and microstructural analysis of a Stenopterygius ichthyosaur from the Jurassic (180 million years ago) reveals that these animals were most likely warm-blooded, had insulating blubber and used their coloration as camouflage from predators.

“Ichthyosaurs are interesting because they have many traits in common with dolphins, but are not at all closely related to those sea-dwelling mammals,” says research co-author Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences and visiting professor at Lund University. “We aren’t exactly sure of their biology either. They have many features in common with living marine reptiles like sea turtles, but we know from the fossil record that they gave live birth, which is associated with warm-bloodedness. This study reveals some of those biological mysteries.”

Johan Lindgren, associate professor at Sweden’s Lund University and lead author of a paper describing the work, put together an international team to analyze an approximately 180 million-year-old Stenopterygius fossil from the Holzmaden quarry in Germany.

“Both the body outline and remnants of internal organs are clearly visible,” says Lindgren. “Remarkably, the fossil is so well-preserved that it is possible to observe individual cellular layers within its skin.”

Researchers identified cell-like microstructures that held pigment organelles within the fossil’s skin, as well as traces of an internal organ thought to be the liver. They also observed material chemically consistent with vertebrate blubber, which is only found in animals capable of maintaining body temperatures independent of ambient conditions.

Lindgren sent samples from the fossil to international colleagues, including Schweitzer. The team conducted a variety of high-resolution analytical techniques, including time-of-flight secondary ion mass spectrometry (ToF SIMS), nanoscale secondary ion mass spectrometry (NanoSIMS), pyrolysis-gas chromatography/mass spectrometry, as well as immunohistological analysis and various microscopic techniques.

Schweitzer and NC State research assistant Wenxia Zheng extracted soft tissues from the samples and performed multiple, high-resolution immunohistochemical analyses. “We developed a panel of antibodies that we applied to all of the samples, and saw differential binding, meaning the antibodies for a particular protein — like keratin or hemoglobin — only bound to particular areas,” Schweitzer says. “This demonstrates the specificity of these antibodies and is strong evidence that different proteins persist in different tissues. You wouldn’t expect to find keratin in the liver, for example, but you would expect hemoglobin. And that’s what we saw in the responses of these samples to different antibodies and other chemical tools.”

Lindgren’s lab also found chemical evidence for subcutaneous blubber. “This is the first direct, chemical evidence for warm-bloodedness in an ichthyosaur, because blubber is a feature of warm-blooded animals,” Schweitzer says.

Taken together, the researchers’ findings indicate that the Stenopterygius had skin similar to that of a whale, and coloration similar to many living marine animals — dark on top and lighter on the bottom — which would provide camouflage from predators, like pterosaurs from above, or pliosaurs from below.

“Both morphologically and chemically, we found that although Stenopterygius would be loosely considered ‘reptiles,’ they lost the scaly skin associated with these animals — just as the modern leatherback sea turtle has,” Schweitzer says. “Losing the scales reduces drag and increases maneuverability underwater.

“This animal’s preservation is unusual, especially for a marine environment — but then, the Holzmaden formation is known for its exceptional preservation. This specimen has given us more evidence that these tissues and molecules can preserve for extremely long periods, and that soft tissue analysis can shed light on evolutionary patterns, relationships, and how ancient animals functioned in their environment.

“Our results were repeatable and consistent across labs. This work really shows what we’re capable of discovering when we perform a multidisciplinary, multi-institutional study of an exceptional specimen.”

Hagfish and lamprey ears, new study


This 2017 video says about itself:

The hagfish is a slime-emitting ocean-dweller that’s remained unchanged for 300 million years–and it shows. It has a skull (but no spine), velvet smooth skin, and a terrifying pit of a mouth that’s lined with rows of razor-sharp teeth.

From RIKEN in Japan:

Evolution of the inner ear: Insights from jawless fish

December 5, 2018

Researchers at the RIKEN Center for Biosystems Dynamics (BDR) and collaborators have described for the first time the development of the hagfish inner ear. Published in the journal Nature, the study provides a new story for inner ear evolution that began with the last common ancestor of modern vertebrates.

Comparing organs among related animals can be helpful when trying to understand the evolutionary process, and will ultimately help us better understand organogenesis — the process through which organs develop. This underlying philosophy helped guide the collaborative effort to study the inner ear led by Shigeru Kuratani at RIKEN BDR.

The story begins with a difference between jawed and jawless vertebrates. Jawed vertebrates like humans have inner ears with three semicircular canals, which are what allow us to sense our position and stay balanced in the world, and especially to sense 3-D acceleration. The fossil record shows that a group of jawless fish from the Paleozoic era only had two semicircular canals. In order to understand the evolutionary changes that led [to] three canals, the team looked at the only two types of jawless vertebrates that still exist on earth: lampreys and hagfish.

Lampreys are thought to have two semicircular canals, while hagfish only have one. However, hagfish are no longer thought to be more primitive than lampreys. A series of molecular biological experiments was able to clarify the issue. Analyzing the regulatory genes that control the development of the semicircular canals showed that the basic pattern of inner ear development is similar for all vertebrates, including lampreys and hagfish. Key genes, such as Tbx1 and Patched were expressed at the same places with the same timing across all three types of vertebrate.

The anterior and posterior canals in jawed vertebrates appear to be genetically homologous to the anterior and posterior parts of the lamprey canal, while the pattern for the single hagfish canal is likely an evolved trait, not a primitive condition. The difference between the jawed and jawless fish is the presence of the common crus, a structure that connects the anterior and posterior canals in jawed vertebrates. The current study could not determine whether the common crus is something that jawed vertebrates gained or something that was lost in jawless vertebrates.

Further analysis focused on the Otx1 gene. This gene is required for proper development of the lateral canal, the third canal that is unique to jawed vertebrates. The researchers found that despite the lack of a lateral canal, lampreys and hagfish both expressed Otx1 in the proper location during development. This was somewhat surprising as its expression was thought to be an advent that led to the evolution of the lateral canal. Instead, it appears that Otx1 expression in the otic vesicle is an ancient feature for all vertebrates.

A more complete understanding will be possible by performing studies with an animal that represents the lineages before jawed and jawless vertebrates diverged.