American migratory birds, new study


This video from the USA says about itself:

12 April 2013

Original documentary about the annual migration of billions of songbirds across the Gulf of Mexico and into North America. Features HD footage of hundreds of colorful songbirds.

Try watching in HD: 720 or 1080p full screen (with fast connections). 1080p is the very highest quality for this movie and looks great!

It seems like the video loads with the player in the middle of the movie, so you have to move it back to the start.

GULF CROSSING: STORY OF SPRING

In the spring hundreds of bird species move from the tropics into North America. As they make their way they eventually face the great barrier of the Gulf of Mexico. This arm of the Atlantic ocean is more than 900 miles wide, and more than 600 miles across from north to south.

While some birds skirt the edge of the water, the overwhelming majority-more than 200 species, and hundreds of millions of individuals-cross the unbroken plain of the gulf in a single flight of 20 or more hours.

Gulf Crossing is a record of trans-gulf migration on America’s southern coast: the expectation of arrival, the surprise each day of what birds appear, and the habitats they are found in. The experience is expanded by a scientific perspective on the phenomenon of migration, describing its geographic shape, the coastal habitats birds rely on, physiological cycles in birds, and the effect of weather patterns on bird flight.

Bird migration along the gulf coast is one of the most exciting and powerful natural experiences you can have. Millions of birds from hundreds of species are passing overhead each day, and you never know what’s going to show up. But despite the hundreds of nature documentaries that are made each year, the story of trans-gulf migration has never really been told before.

Gulf Crossing is an attempt to document this remarkable and moving natural phenomenon. The six episodes provide a comprehensive exploration of the Gulf crossing, from Spring to Fall, covering migration along the Upper Texas Coast, the arrival and breeding of birds in the north, and Fall migration in north Florida.

I hope this documentary will increase awareness and appreciation of America’s immense but vanishing natural heritage.

Gulf Crossing is free to use in any classroom or group setting. For more info on use, see the Creative Commons License. If you are interested in downloading the file to show to groups, please contact me.

From the Cornell Lab of Ornithology in the USA today:

eBird Data Reveal Crucial Role for Wintering Grounds

After merging bird observations from eBird along with projections for land use and climate change, a new Cornell Lab study finds that loss of habitat on the wintering grounds may be the greatest threat faced by 21 species of eastern forest birds that winter in Central America in the coming decades. These flycatchers, warblers, and vireos spend nearly 60% of the year on their wintering grounds. The study is the first to measure the impact of climate and land-use change throughout the birds’ entire life cycle, including breeding, wintering, and migration. Read more.

Brittle stars fossils discovery in Australia


This video says about itself:

13 August 2017

Australia was a different place 275 million years ago – wild storms surged through icy seas, and marine animals lived a tenuous existence. But brittle stars had a survival strategy.

From the University of Cambridge in England:

Meadow of dancing brittle stars shows evolution at work

August 14, 2017

Newly-described fossil shows how brittle stars evolved in response to pressure from predators, and how an ‘evolutionary hangover’ managed to escape them.

Researchers have described a new species of brittle star, which are closely related to starfish, and showed how these sea creatures evolved in response to the rise of shell-crushing predators during the late Palaeozoic Era. The results, reported in the Journal of Systematic Palaeontology, also suggest that brittle stars evolved new traits before the largest mass extinction event in Earth’s history, and not after, as was the case with many other forms of life.

A fossilised ‘meadow’ of dancing brittle stars — frozen in time in the very spot that they lived — was found in Western Australia and dates from 275 million years ago. It contains several remarkably preserved ‘archaic’ brittle stars, a newly-described genus and species called Teleosaster creasyi. They are the last known complete brittle stars of their kind, an evolutionary hangover pushed to the margins of the world’s oceans by the threat from predators.

The researchers, from the University of Cambridge, suggest that while other species of brittle stars evolved in response to predators such as early forms of rays and crabs, these archaic forms simply moved to where the predators weren’t — namely the seas around Australia, which during the Palaeozoic era was pushed up against Antarctica. In these cold, predator-free waters, the archaic forms were able to grow much larger, and lived at the same time as the modern forms of brittle star, which still exist today.

Brittle stars consist of a central disc and five whip-like appendages, which are used for locomotion. They first appear in the fossil record about 500 million years ago, in the Ordovician Period, and today there are about 2,100 different species, mostly found in the deep ocean.

Early brittle stars were just that: brittle. During the Palaeozoic Era, when early shell-crushing predators first appeared, brittle stars made for easy prey. At this point, a split in the evolutionary tree appears to have occurred: the archaic, clunky brittle stars moved south to polar waters, while the modern form first began to emerge in response to the threat from predators, and was able to continue to live in the warmer waters closer to the equator. Both forms existed at the same time, but in different parts of the ocean.

“The threat from predation is an under-appreciated driver of evolutionary change,” said study co-author Dr Kenneth McNamara of Cambridge’s Department of Earth Sciences. “As more predators began to appear, the brittle stars started to evolve more flexible bodies, which enabled them to either burrow into the sediment, or to move more rapidly to escape.”

About 250 million years ago, the greatest mass extinction in Earth’s history — the Permian-Triassic extinction event, or the “Great Dying” — occurred. More than 90% of marine species and 70% of terrestrial species went extinct, and as a result, most surviving species underwent major evolutionary changes as a result.

“Brittle stars appear to have bucked this trend, however,” said co-author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences. “They seem to have evolved before the Great Dying, into a form which we still see today.”

Meadows of brittle stars and other invertebrates such as sea urchins and starfish can still be seen today in the seas around Antarctica. As was the case during the Palaeozoic, the threat from predators is fairly low, although the warming of the Antarctic seas due to climate change has been linked to the recent arrival of armies of king crabs, which represent a real threat to these star-filled meadows.

Ancient Triassic reptile was not aquatic


LAND LIVING Eusaurosphargis dalsassoi, an ancient lizardlike critter (illustrated), wouldn’t swim well, scientists now say, arguing the creature’s style of motion and protective coverings were more suited to land. T. Scheyer/Palaeontological Institute and Museum/University of Zurich, Switzerland

By Ashley Yeager, 7:00am, August 9, 2017:

Fossil find suggests this ancient reptile lurked on land, not in the water

Exquisitely preserved specimen may overturn ideas about spiny creature’s home

A round belly, stubby feet and a tapering tail made one armored reptile a lousy swimmer. Despite earlier reports, Eusaurosphargis dalsassoi might not have swum at all, scientists now say.

E. dalsassoi was first identified in 2003. Fossils were found near Monte San Giorgio at the Swiss-Italian border alongside the remains of marine reptiles and fish that lived roughly 240 million years ago. That association led scientists to conclude the creature was aquatic. But a complete skeleton of E. dalsassoi unearthed in 2002 in the Swiss Alps and recently assembled contradicts that idea.

At just under 20 centimeters long, the fossil, probably of a youngster, shows that E. dalsassoi widened at the stomach and slithered forward with stiff elbow and knee joints and spadelike claws. That’s not a swimmer’s build, paleontologist Torsten Scheyer of the University of Zurich and colleagues report June 30 in Scientific Reports.

Armed with rows of small spikes along its back and spear-shaped plates framing its head, sides and tail, the animal resembled today’s girdled lizards. The researchers speculate that this particular E. dalsassoi died on a beach and then got washed into the ocean.

Biggest dinosaur ever discovered


This video from the American Museum of Natural History in the USA says about itself:

14 January 2016

Measuring 122 feet, the Museum’s new exhibit, The Titanosaur, is big–so big that its head extends outside of the Museum’s fourth-floor gallery where it is now on permanent display.

This species of dinosaur, a giant herbivore that belongs to a group known as titanosaurs, is so new that it has not yet been formally named by the paleontologists who discovered it. The Titanosaur lived in the forests of today’s Patagonia about 100 to 95 million years ago, during the Late Cretaceous period, and weighed 70 tons. It is one of the largest dinosaurs ever discovered.

The fossils on which this cast is based were excavated in the Patagonian desert region of Argentina by a team from the Museo Paleontologico Egidio Feruglio led by José Luis Carballido and Diego Pol, who received his Ph.D. at the American Museum of Natural History.

In this video, Dr. Mark Norell, chair and Macaulay Curator in the Division of Paleontology, describes how such a massive animal could have supported its own weight and why the Titanosaur is one of the more spectacular finds during what he describes as “the golden age of paleontology.”

Learn more about the Titanosaur here.

Then, this dinosaur had no official name yet. Now, it has: Patagotitan mayorum.

It was about 40 meter long, making it the biggest land animal ever.

The discovery was by scientists of the Museo Paleontológico Egidio Feruglio (MEF) in Argentina.

From Proceedings of the Royal Society B:

A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs

José L. Carballido, Diego Pol, Alejandro Otero, Ignacio A. Cerda, Leonardo Salgado, Alberto C. Garrido, Jahandar Ramezani, Néstor R. Cúneo, Javier M. Krause

Published 9 August 2017

Abstract

Titanosauria was the most diverse and successful lineage of sauropod dinosaurs. This clade had its major radiation during the middle Early Cretaceous and survived up to the end of that period. Among sauropods, this lineage has the most disparate values of body mass, including the smallest and largest sauropods known.

Although recent findings have improved our knowledge on giant titanosaur anatomy, there are still many unknown aspects about their evolution, especially for the most gigantic forms and the evolution of body mass in this clade.

Here we describe a new giant titanosaur, which represents the largest species described so far and one of the most complete titanosaurs. Its inclusion in an extended phylogenetic analysis and the optimization of body mass reveals the presence of an endemic clade of giant titanosaurs inhabited Patagonia between the Albian and the Santonian. This clade includes most of the giant species of titanosaurs and represents the major increase in body mass in the history of Titanosauria.

Goldfish survive harsh winters with alcohol


This video says about itself:

Goldfish go months without oxygen by making alcohol inside cells

11 August 2017

Goldfish and crucian carp have evolved enzymes that turn carbohydrates into alcohol when no oxygen is available – helping the fish survive in ice-locked pools. Read more here.

From the University of Liverpool in England:

How goldfish make alcohol to survive without oxygen

August 11, 2017

Scientists at the Universities of Oslo and Liverpool have uncovered the secret behind a goldfish’s remarkable ability to produce alcohol as a way of surviving harsh winters beneath frozen lakes.

Humans and most other vertebrate animals die within a few minutes without oxygen. Yet goldfish and their wild relatives, crucian carp, can survive for days, even months, in oxygen-free water at the bottom of ice-covered ponds.

During this time, the fish are able to convert anaerobically produced lactic acid into ethanol, which then diffuses across their gills into the surrounding water and avoids a dangerous build-up of lactic acid in the body.

The molecular mechanism behind this highly unusual ability, which is unique among vertebrates and more commonly associated with brewer’s yeast, has now been uncovered and is published in the journal Scientific Reports.

The international team has shown that muscles of goldfish and crucian carp contain not just the usual one, but two sets of the proteins normally used to channel carbohydrates towards their breakdown within a cell’s mitochondria — a key step for energy production.

While one set of these proteins appears very similar to that in other species, the second set is strongly activated by the absence of oxygen and shows a mutation that allows channelling of metabolic substrates to ethanol formation outside the mitochondria.

Further genetic analyses suggest that the two sets of proteins arose as part of a whole genome duplication event in a common ancestor of goldfish and crucian carp some 8 million years ago.

Dr Michael Berenbrink, an evolutionary physiologist at the University of Liverpool, said: “During their time in oxygen-free water in ice-covered ponds, which can last for several months in their northern European habitat, blood alcohol concentrations in crucian carp can reach more than 50 mg per 100 millilitres, which is above the drink drive limit in these countries.

“However, this is still a much better situation than filling up with lactic acid, which is the metabolic end product for other vertebrates, including humans, when devoid of oxygen.”

Lead author Dr Cathrine Elisabeth Fagernes, from the University of Oslo, said: “This research emphasises the role of whole genome duplications in the evolution of biological novelty and the adaptation of species to previously inhospitable environments.

“The ethanol production allows the crucian carp to be the only fish species surviving and exploiting these harsh environments, thereby avoiding competition and escaping predation by other fish species with which they normally interact in better oxygenated waters.

“It’s no wonder then that the crucian carp’s cousin the goldfish is arguably one of the most resilient pets under human care.”

The work is the result of a collaboration between scientists at the University of Liverpool, UK, and the University of Oslo, Norway. The work was funded by the Research Council of Norway.

Bahamas pupfish, new study


Bahamas pupfish

This picture about Bahamas pupfish shows San Salvador Island generalists (red), molluscivores (green), large-jawed scale-eaters (dark blue), small-jawed scale-eaters (light blue), and outgroup species (black) in the Caribbean, California, and Mexico. Credit: Emilie Richards and Christopher Martin; CC-BY.

From PLOS:

San Salvador pupfish acquired genetic variation from island fish to eat new foods

Study finds that ecological and genetic factors both contributed to rise of new pupfish species

August 10, 2017

Pupfish living in salty lakes on San Salvador Island were able to diversify into multiple species with different eating habits, in part, by interbreeding with pupfish from other islands in the Caribbean, report Emilie Richards and Christopher Martin, of the University of North Carolina at Chapel Hill, August 10, 2017 in PLOS Genetics.

Pupfish are small, brightly colored fish that commonly live in coastal areas and salty lakes and feed off of algae. But on San Salvador Island in the Bahamas, a group of pupfish has undergone adaptive radiation, a process where existing species rapidly evolve and differentiate into new species, to take advantage of a new environment. Where most pupfish species eat algae, one San Salvador species has a protruding nasal region that allows it to eat snails, while another has enlarged jaws that enable it to bite the scales off of other fish. To understand why these specialized species evolved only on San Salvador Island, despite the availability of scales and snails across the Caribbean, the researchers used whole genomes to identify regions of the San Salvador pupfish genome that came from outside sources.

They examined 42 pupfish genomes collected from populations on San Salvador Island, two distant Caribbean islands, Laguna Chichancanab in Mexico, and Devil’s Hole in California, to identify regions of the genome that have been exchanged between San Salvador Island and outside pupfish populations. They identified 11 gene variants in the San Salvador fish that came from other Caribbean pupfish populations, with four of these regions known to affect jaw size and shape, traits important in the evolution of their specialized diets.

The study suggests that multiple outside sources of genetic variation contributed to the adaptations found in pupfishes on San Salvador Island. These findings indicate that a complex suite of factors, including breeding with related species, in addition to new ecological opportunities, may be necessary for adaptive radiations to occur.

“The really intriguing thing here is that new species are assembled from different pots of genetic variation over a very large range. Our own species is likely no different,” says study corresponding author Dr. Martin.

Blue lizards less scared of humans with blue T-shirts


This video says about itself:

California Wildlife — Western Fence Lizard, “push-ups”, blue neck/undersides

20 August 2014

Ronald Caspers Wilderness Park, San Juan Capistrano, Orange County, California, USA.

From PLOS:

The color of people’s clothing affects lizard escape behavior

Lizards with blue patches tolerate closer approaches when people wear dark blue T-shirts

August 9, 2017

The color of T-shirts people wear affects escape behavior in western fence lizards, according to a study published August 9, 2017 in the open-access journal PLOS ONE by Breanna Putman from University of California, Los Angeles and the Natural History Museum of Los Angeles County, U.S.A., and colleagues.

Animals often see people as predators, and animal behavior can be affected by nuanced aspects of human behavior including gaze direction, camera shutter noise, and clothing color. For example, several species of birds with orange or red body patches are more tolerant of people wearing orange or red. This tolerance has been explained by the species confidence hypothesis, which suggests that birds are less fearful of colors found on their own bodies. However, most of these bird studies tested responses to observers wearing bright orange versus dark gray, making it impossible to determine whether the birds responded to the color itself or to its detectability against the background environment.

Putman and colleagues tested the species confidence hypothesis further on western fence lizards in Southern California. Males of this species communicate with blue patches on the abdomen and throat. Putman wore T-shirts of different colorsm dark blue, light blue, red and gray, and measured how close she could approach lizards before they fled. After they fled, she determined how easy they were to catch. She approached lizards that were already used to human presence as well as lizards that had little experience with humans in their protected nature reserve. Altogether, she did nearly 30 trials for each T-shirt color. In addition, the researchers used reflectance spectroscopy to determine the conspicuousness of the T-shirts in the environment.

Irrespective of the lizard’s previous interactions with human, the study found that western fence lizards are preferentially biased toward dark blue, supporting the species confidence hypothesis. Notably, lizards fled at shorter distances when Putman wore dark blue than when she wore red (an average of roughly 100 versus 200 centimeters, respectively). In addition, she captured lizards about twice as often when wearing dark blue than when wearing red (84% versus about 40% of the time, respectively). Importantly, because the pattern by which lizards fled from different colored T-shirts does not associate with their conspicuousness (based on spectral sensitivities), this suggests that they are responding to color and not detectability.

The researchers suggest that the colors scientists wear in the field could affect ease of capture as well as behavior of study species. Moreover, the colors ecotourists and hikers wear could minimize disturbances to animals, which is critical because fleeing long distances when there is no threat could have fitness consequences. As Breanna Putman says: “What we wear can have indirect effects on animals through changes in their behavior.”