Thursday, May 27, 2010

Prehistoric Birds Were Poor Flyers

 


Archaeopteryx. (Credit: Image courtesy of Todd Marshall)

Prehistoric Birds Were Poor Flyers, Research Shows

ScienceDaily (May 26, 2010) — The evolution of flight took longer than previously thought with the ancestors of modern birds "rubbish" at flying, if they flew at all, according to scientists.


Archaeopteryx, the theropod dinosaur believed to be the earliest bird, was discovered 150 years ago but debates about how flight evolved still persist. The two theories are that flight evolved in running bipeds through a series of short jumps or that Archaeopteryx leapt from tree to tree using its wings as a balancing mechanism.
Dr Robert Nudds at The University of Manchester is carrying out a series of biomechanical investigations to shed light on the subject with his colleague Dr Gareth Dyke at University College Dublin.

For their latest paper Dr Nudds and Dr Dyke applied a novel biomechanical analysis to the flight feathers of the early birds Archaeopteryx and Confuciusornis to find out if they were strong enough to allow flight.
They found that the dinosaur feathers' much thinner central stem (rachis) must have been solid or they would have broken under the lift forces generated during flight or by gusts of wind. This solid structure is very different to modern birds, whose rachises are broader, hollow straws. If the dinosaurs' feathers had had hollow rachises, they would not have been able to fly at all.

"These are surprising results," says Dr Nudds, whose findings are published in Science.

"I thought the feathers would be strong enough with a hollow rachis to fly but they weren't. Even with a solid rachis, they were not very good. These dinosaurs were rubbish at flying.

"This pushes the origin of flapping flight to after Archaeopteryx and Confuciusornis. It must have come much later."

It is impossible to tell from fossils whether the rachises were solid or hollow. However Dr Nudds, at Manchester's Faculty of Life Sciences, believes the dinosaurs' feathers were solid and therefore they could fly, but very poorly.

"The fossilsof Confuciusornis and Archaeopteryx suggest flight and at this stage it would be a brave person to say they couldn't fly" he says.

"However their feathers must have been very different to modern birds and they were poor fliers. I believe the feathers were originally for insulation or display purposes then they found that by elongating them they had a parachuting surface, then a gliding surface.

"Archaeopteryx and Confuciusornis are still at a very early stage in the evolution of flight."

Dr Nudds' and Dr Dykes' work builds on their previous paper, in the journal Evolution, which investigated how the movement of feathered dinosaur forelimbs evolved into flapping flight. Again they found the flight was a consequence of gradual changes in wing shape and movement -- a long, slow evolution.

Dr Nudds adds: "Our analysis also shows that Confuciusornis, which is younger by 25 million years, was worse at flying than Archaeopteryx. This raises the further question of lineage -- did the dinosaur-bird line branch off, giving rise to flying and flightless birds?"

He and Dr Dyke plan to analyse other fossilized feathers to find out when flapping flight evolved. However such specimens are rare.

"I don't mind," says Dr Nudds. "It makes it more exciting and all the more intriguing.":

Story Source:
Adapted from materials provided by University of Manchester.

Journal Reference:
  1. R. L. Nudds, G. J. Dyke. Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability. Science, 2010; 328 (5980): 887 DOI: 10.1126/science.1188895

University of Manchester. "Prehistoric Birds Were Poor Flyers, Research Shows." ScienceDaily 26 May 2010. 27 May 2010 <http://www.sciencedaily.com­ /releases/2010/05/100526100612.htm>.

Tuesday, May 25, 2010

Penguin Research

Since "Penguin Science" first graced the net with its presence, a murmur of excitement and anticipation arose from penguinologists around the globe. David Ainsley, reknown author and researcher, headlines the programs currently underway at the Adelie Sea lab on the coast of the Ross Sea. There is also a CD that is inexpensive and a must for armchair penguinologists. However, this CD is not just for fans. It is a great teaching tool for kids who are in dire need to understand the delicate ecosystem of Antarctica.  The site, itself, contains numerous papers, many of them of recent origin, that provide a rich repository in penguin knowledge.


Below is an example of what you'll find at "Penguin Science." Also, there is a section on climate change and the effects on penguins. While you're there, take a look at all the great photography. It is my hope that everyone will partake of the benefits that this site offers. Lastly, kudos to those brave scientists, who, despite the cold and foul weather of our southernmost continent, manage to create a larger body of knowledge that can help save the penguins. These folks are truly the unsung heroes of the natural world. 


wiinterrr

GEOGRAPHIC STRUCTURE OF ADELIE PENGUIN POPULATIONS: DEMOGRAPHY OF COLONY GROWTH
Principal Investigators: D Ainley, G Ballard, P Wilson, K Dugger, P Lyver
RESULTS OF PRIOR NSF SUPPORT
OPP 9526865, 9814882, 0125608 (current study): Factors regulating population size and colony distribution of Adélie Penguins in the Ross Sea. $1,800,000. 9 years: 23 August 1996-31 July 2005. Co-PIs: D. Ainley, G. Ballard, L. Ballance, K. Dugger, N. Nur, G. Rau, and C. Ribic. Collaborators at LandCare Research NZ (P. Wilson, K Barton), funded independently.

We have completed 8 of 9 NSF-funded field seasons in which we attempt to explain why 1) colonies in the southern portion of the Adélie Penguin range (e.g., Ross Sea) increased in size noticeably during the 1970-80s and then leveled off (Fig. 1); 2) the rate of increase and variability has been much greater at smallest colonies (and minimal at large colonies); and 3) adjacent colonies ranged greatly in size in the first place. To investigate these issues, we chose an isolated cluster of 4 colonies (a metapopulation) on or near Ross Island that together comprise 8% of the world population of this species (30% of which lies in the Ross Sea) and range three orders of magnitude from among the largest to the smallest for this species: Ross Island (Cape Crozier 130,000; Cape Bird 36,000; Cape Royds 4,000); and Beaufort Island 38,000 pairs. A 5th, incipient colony, Cape Barne (also on Ross Is), has been occupied irregularly in recent years, and at times throughout the Holocene, by 20 or more pairs. Only the colony at Beaufort Island is space limited. Our basic plan was to compare the reproductive and foraging ecology and effort of penguins nesting at colonies of different size, as well as to assess demographic parameters.

 Click here to visit "Penguin Science."

Thursday, May 13, 2010

Scientists to track penguin migration

Southwest Marine Fisheries Service
Chinstrap penguins are one of the species that will be tracked by the Southwest Marine Fisheries Service.

Scientists to track penguin migration

Tuesday, May 11, 2010 at 7:35 p.m.
Chinstrap penguins are one of the species that will be tracked by the Southwest Marine Fisheries Service.
- Southwest Marine Fisheries Service 

McKenzie Mudge, left, and Kevin Pietrzak tag a gentoo penguin this year at Cape Shirreff, Antarctica.
To follow Antarctic penguins and seals being tracked by the Southwest Fisheries Science Center, go to uniontrib.com/taggingmap.

Do Antarctic penguins and seals have time to chill out in the winter, or must they swim miles to forage for food? Do their travels resemble the depictions in movies like “Happy Feet”?
Now you can track the animals’ movements, thanks to the Southwest Fisheries Science Center in La Jolla.
Scientists from the facility have attached satellite tags to 61 of the creatures. They and the public will be able to see the results on an online map.

Gentoo and chinstrap penguins and fur, leopard and Weddell seals recently were outfitted with cell phone-sized transmitters that send information to satellites whenever the animals surface. The researchers will process information on the species’ range of movement, the places they frequent most and the temperatures and salinity levels of those areas.

“No one has ever done this many species from one location and see how they disperse over the winter,” said Mike Goebel, a researcher for the fisheries center, which is run by the National Oceanic and Atmospheric Administration.

“Prior to doing this study, we had no idea which species remain in the Antarctic (for the winter) and which species migrate.”

Federal researchers typically monitor the Antarctic ecosystem from October through March, which is summertime there.

“Our research has led us to believe that the winter activities of these animals are important to their reproductive success,” said biologist Amy Van Cise from the center.

“For example, their ability to forage during the winter is linked to their ability to reproduce and raise offspring the following summer.”

Source

Wednesday, May 12, 2010

X-Rays Reveal Chemical Link Between Birds and Dinosaurs

Using the bright X-ray beam of the Stanford Synchrotron Radiation Lightsource, located at the Department of Energy's SLAC National Accelerator Laboratory, an international team of paleontologists, geochemists and physicists has revealed this transformative glimpse into one of the most important fossils ever discovered: the Archaeopteryx, a half-dinosaur/half-bird species. In this image, the main panel shows a false color view of the Thermopolis Archaeopteryx. The image is a composite blend of scans of the elements phosphorus, silicon, sulfur, and iron. The bright colors in the wing areas show how part of the feather chemistry has been preserved. The top left panel is an anaglyph made from phosphorus and iron showing detail of skull and manus claw. The top right panel is another anaglyph, here showing fine detail of the skull using only phosphorous. (Credit: This image was created by K.G. Huntley from data produced at the Stanford Synchrotron Radiation Lightsource, located at the Department of Energy's SLAC National Accelerator Laboratory. This work was published today in Proceedings of National Academy of Science.)

X-Rays Reveal Chemical Link Between Birds and Dinosaurs

ScienceDaily (May 11, 2010) — Researchers have found that a 150 million year old "dinobird" fossil, long thought to contain nothing but fossilized bone and rock, has been hiding remnants of the animal's original chemistry. Using the bright X-ray beam of the Stanford Synchrotron Radiation Lightsource, located at the Department of Energy's SLAC National Accelerator Laboratory, an international team of paleontologists, geochemists and physicists has revealed this transformative glimpse into one of the most important fossils ever discovered: the Archaeopteryx, a half-dinosaur/half-bird species.

"Archaeopteryx is to paleontology what Tutankhamen is to archaeology. It's simply one of the icons of our field," said University of Manchester paleontologist Phil Manning. "You would think after 150 years of study, we'd know everything we need to know about this animal. But guess what -- we were wrong."

When the first Archaeopteryx specimen was uncovered a century and a half ago, just a year after Charles Darwin published On the Origin of Species, the discovery provided the strongest evidence yet for the theory of evolution. In the intervening years, nine additional specimens have been found, including the Thermopolis specimen that the researchers studied at SSRL. Like the other Archaeopteryx specimens, this fossil has undergone extensive visual analyses and even CT scans in the past, none of which revealed that beneath the surface hid the dinobird's chemical remains. But that was before researchers placed it under the X-ray beam at SSRL.

Using light source technology primarily utilized for advanced energy-related research in materials science, biology, and other fields, the scientists traced SSRL's hair-thin X-ray beam across the Thermopolis Archaeopteryx fossil. By recording how the X-rays interacted with the fossil, the researchers were able to identify very precisely the locations of chemical elements hidden within. From this, they created the first maps of the dinobird's chemistry, revealing half a dozen chemical elements that were actually part of the living animal itself. In almost every element studied, the researchers found significantly different concentrations in the fossil than in the rock that surrounds it, confirming that the observed elements are indeed remnants of the dinobird and not merely chemicals that leached from the surrounding rock into the fossil.

"People have never used a technique this sensitive on Archaeopteryx before," said SLAC physicist Uwe Bergmann, who led the X-ray scanning experiment. "Because the SSRL beam is so bright, we were able to see the teeniest chemical traces that nobody thought were there."

The chemical maps, published today in Proceedings of National Academy of Sciences, show that portions of the feathers are not merely impressions of long-decomposed organic material -- as was previously believed -- but actual fossilized feathers that contain phosphorous and sulfur, elements that comprise modern bird feathers. Trace amounts of copper and zinc were also found in the dinobird's bones; like birds today, the Archaeopteryx may have required these elements to stay healthy.

"We talk about the physical link between birds and dinosaurs, and now we have found a chemical link between them," said University of Manchester geochemist Roy Wogelius, corresponding author on the paper. "In the fields of paleontology and geology, people have studied bones for decades. But this whole idea of the preservation of trace metals and the chemical remains of soft tissue is quite exciting."

"The discovery that certain fossils retain the detailed chemistry of the original organisms offers scientists a new avenue for learning about long-extinct creatures," said CMW Institute researcher Bob Morton.

As a result, the research has the potential to change the way a paleontologist views a fossil. "We're able to read so much more into these organisms now using this technology -- we're literally touching ghosts," said Wogelius. "Chemistry is the real key in the future of paleontology. It's a paradigm shift."

However, only bones and fossils that have not been removed from the surrounding rock and soil -- as with the Thermopolis Archaeopteryx -- are best suited for this type of analysis. That's because it's necessary for researchers to compare the elements found within the specimen to those found within the neighboring rock or soil in order to be able to account for transfer from one to the other.

As a result of this work, Manning said, he wouldn't be surprised if "future excavations look more like CSI investigations where people look for clues at a scene of a crime. There's info that's still there that can't be seen with the naked eye. We can only see these really quite valuable pieces of data with the synchrotron eye."

This research was conducted by Uwe Bergmann (SLAC), Bob Morton (CMW Institute), Phil Manning (University of Manchester and University of Pennsylvania), William Sellers (University of Manchester), Sam Farrar (Black Hills Institute of Geological Research), Ken Huntley (CMW Institute), Roy Wogelius (University of Manchester), and Peter Larson (University of Manchester and Black Hills Institute of Geological Research). The collaboration wishes to thank the Wyoming Dinosaur Center, which loaned the fossil for analysis; and the Black Hills Institute of Geological Research, which arranged the loan.

Story Source:
Adapted from materials provided by DOE/SLAC National Accelerator Laboratory. Original article written by Kelen Tuttle.

Journal Reference:
  1. U. Bergmann, R. W. Morton, P. L. Manning, W. I. Sellers, S. Farrar, K. G. Huntley, R. A. Wogelius, P. Larson. Archaeopteryx feathers and bone chemistry fully revealed via synchrotron imaging. Proceedings of National Academy of Sciences, 2010; DOI: 10.1073/pnas.1001569107

DOE/SLAC National Accelerator Laboratory. "X-Rays Reveal Chemical Link Between Birds and Dinosaurs." ScienceDaily 11 May 2010. 12 May 2010 <http://www.sciencedaily.com­ /releases/2010/05/100510151348.htm>.

Tuesday, May 11, 2010

Fossil reveals early bird plumage

Fossil reveals early bird plumage

Page last updated at 23:46 GMT
Archaeopteryx (Wogelius)
Archaeopteryx fossils capture a snapshot of evolution


A new study of a 150-million-year-old fossil of an Archaeopteryx has shown that remnants of its feathers have been preserved.
Archaeopteryx is regarded as a "missing link" that documents a fabulous transition from dinosaur to bird.
The researchers say that it may soon be possible to work out the colours of feathers sported by these creatures.
The new work is published in the journal Proceedings of the National Academy of Sciences (PNAS).
But the authors warn museum curators not to be overzealous in cleaning up fossils for display in case they destroy vital scientific data.
Archaeopteryx is the most iconic of fossils: Many of the specimens beautifully capture this snapshot of evolution - showing the creature's skeleton, feathers and teeth in great detail.
People have never used a technique this sensitive on Archaeopteryx before Dr Uwe Bergmann SLAC
But now a new scanning technique has revealed that one fossil contains fragments of the original feathers - rather than just being an imprint of an animal whose remains had long ago disintegrated into the dust.
The bad news though is that museum curators have inadvertently chipped and scrubbed off a lot more fragments of the creature's feathers and skin fragments as they prepared the fossil for public display to highlight the bones.
But researchers are hopeful they'll be able to study other specimens and obtain more details of the chemistry of the creature's feathers and possibly learn more about their colour.
Dr Roy Wogelius, from University of Manchester, who was among those who made the discovery, is keen to alert curators that the new scanning techniques reveal that many precious fossils contain more than just the remnants of bone.
"One of the things we are very concerned about is that some of the original information has been lost forever," he said.
Archaeopteryx (Wogelius)


One fossil contains fragments of the original feathers. "The preparation and curation of (fossils) needs to take account of the fact that there may be very, very small quantities of chemical remains which curators can tend to remove."
The details were obtained by firing intense X-rays at the sample generated by a so-called synchrotron radiation source at the Stanford Linear Accelerator in California, US.
Dr Uwe Bergmann, who led the X-ray scanning experiment at SLAC, said: "People have never used a technique this sensitive on Archaeopteryx before.
"Because the beam is so bright, we were able to see the teeniest chemical traces that nobody thought were there."
Another member of the team, Dr Phil Manning, from Manchester University, believes that the study shows there's now a new way to study long-extinct creatures.
"I wouldn't be surprised if future excavations look more like CSI investigations where people look for clues at a scene of a crime," he said.



In the bones
 
As well as identifying the feathers the research team also found that the creature's bones have a chemical composition similar to those of birds lving today.
"To me that's quite exciting," said Dr Wogelius. "It establishes a nutrient link between Archaeopteryx and modern birds. If you have a pet bird such as a budgie or a paraquet the key nutrients to get right for your pet's health are copper and zinc."
The researchers have learned all they can from this particular specimen. But they hope that their work shows there's more to be learned from fossils and that museum curators should now approach the process of preparing fossils for display with this in mind.
"We've shown that this kind of approach can resolve chemical information that no one has ever seen," according to Dr Wogelius.
"It's an extremely important result for looking at other fossils and it means that there's a lot more richness in chemical detail that in the past has been missed."

Source

Wednesday, May 5, 2010

Reprint of older finding that aids the bird-dino connection

New Feathered Dinosaur Found; Adds to Bird-Dino Theory
Kevin Holden Platt in Beijing
for National Geographic News
January 16, 2009
 
A fossil of a primitive feathered dinosaur uncovered in China is helping scientists create a better model of how dinosaurs evolved into modern birds.
The winged dinosaur is still in the process of being dated, and might have lived toward the end of the Jurassic period, which lasted from 208 to 144 million years ago.
In many ways, it is "more basal, or primitive, than Archaeopteryx," said paleontologist Xu Xing at Beijing's Institute of Vertebrate Paleontology and Paleoanthropology. Archaeopteryx, the earliest known bird, lived 150 million years ago.
The protobird is "very close to the point of divergence" at which a new branch of winged dinosaurs first took flight, said Xu.
The new species, called Anchiornis huxleyi, was discovered in the ashes of volcanoes that were active during the Jurassic and Cretaceous (144 to 65 million years ago) periods in what is now northeastern China.
(Read about the prehistoric world.)
Anchiornis, which is Greek for "close to bird," measured just 13 inches (34 centimeters) from head to tail and weighed about 4 ounces (110 grams).
The dinosaur's body and forelimbs were covered with feathers, and it "might have had some aerial capability," Xu said.
"Anchiornis is one of the smallest theropod dinosaurs ever uncovered," Xu explained. Theropods were a group of carnivorous dinosaurs that walked on two legs.

Taking Wing
 
The fossil provides new clues about how feathers, wings, and flight progressively appeared among theropods, along with evidence that certain types of feathered dinosaurs decreased in stature even as their forelimbs became elongated.
The compact structure of Anchiornis "reinforces the deduction that small size evolved early in the history of birds," Xu explained.

"[Anchiornis] exhibits some wrist features indicative of high mobility, presaging the wing-folding mechanisms seen in more derived birds," he said.
"The wrist is a big part of the formation of wings, and pivotal to flight," Xu added. "During flight, steering and flapping greatly depend on the wrist."
Despite this protobird's relatively advanced feathers and wrist, it is unclear if Anchiornis could actually engage in powered flight.
"Behavior and biomechanics are very difficult to determine solely from the fossil record, and perhaps flight is impossible to determine," said Mark Norell, chairman and curator of the division of paleontology at the American Museum of Natural History in New York.
"Feathers have lots of functions, and probably evolved as thermoregulators," said Norell, who closely examined the fossil during a trip to Beijing.
"Dinosaurs might have used feathers for sexual display or to make themselves appear bigger, or as camouflage to avoid predators," he said.
Patterns of spots and bars evident on one species of feathered dinosaur from China might have functioned as a camouflage defense, Norell added.

(Related: "First Dinosaur Feathers for Show, Not Flight?" [October 22, 2008].)

Prehistoric Paradise
 
Xu said that the region in northeastern China where most of the world's feathered dinosaurs, including Anchiornis, have been discovered is a virtual paradise for dinosaur hunting.
"This area has three circles of volcanic activity," with eruptions that intermittently covered and preserved entire biospheres starting from the early Jurassic.
"Volcanos periodically killed the animals and plants and preserved them perfectly in volcanic ash," he said.
"Sometimes the volcanic ash even preserves soft tissues, leaving behind an exceptional 3-D fossil."

Source

And their feathers weren't used for flying...

Two feathered dinosaurs, one young and one old.
An artist's rendering of the two feather types on Similicaudipteryx.
Image courtesy Xing Lida and Song Qijin
Charles Q. Choi
Published April 28, 2010

Newfound fossils of a feathered dinosaur suggest that the extinct reptiles might have possessed a diversity in plumage types that puts modern birds to shame. 

Farmers in northeastern China have unearthed two roughly 125-million-year-old specimens of the dinosaur Similicaudipteryx, a member of the group called the oviraptorosaurs, which are believed to be ancestors of birds.

(See the first pictures of "true color" feathered dinosaurs.)

The species, most likely a plant-eater, was first described in 2008. It had robust jaws similar to those of other oviraptorosaurs, but with two unusually large buck teeth.

The two new fossils belong to a pigeon-size juvenile dinosaur thought to be just a year or two old and a three- to four-year-old duck-size youth.

The younger animal's fossil included short ribbonlike feathers. On its tail, each feather was just 1.6 inches (4 centimeters) long, while on its arms a typical feather was less than 0.8 inch (2 centimeters) long. (Related: "Dino-Era Feathers Found Encased in Amber.")

By contrast, the older dinosaur sported long quills, with each tail feather measuring 13.7 inches (35 centimeters) long and a typical arm feather measuring roughly 9.8 inches (25 centimeters) long.
The findings suggest feathered dinosaurs might have undergone a flurry of changes as they matured—unlike anything seen in modern birds, said study co-author Xing Xu of the Chinese Academy of Sciences in Beijing.

Dinosaur's Ribbonlike Feathers "Really Bizarre"

Modern birds continuously replace old feathers with new ones. But birds completely change the types of feathers in their coats just once their entire lives: when they switch from warm down to their adult plumage.
Very young dinosaurs are thought to have been covered in down, so the new find suggests that dinosuars went through at least three stages of feather types: full down, to a mix of down and "ribbons," to down and quills.
The long quills on the older Similicaudipteryx are much like those seen on modern birds, and they might have served as ornaments or to help the dinosaur balance itself as it ran. (Related: "First Dinosaur Feathers for Show, Not Flight?")

The younger dinosaur's ribbonlike feathers are superficially similar to some specialized plumes seen today, for example, on birds of paradise. But the ancient feathers are actually a type that has been lost in the course of evolution, and the role they played on the younger juvenile remains unknown.

These extinct feathers would not have been useful for warmth, for example, given how flat they are, Xu said.
While the "ribbons" might have served as ornaments, "in modern animals, structures used for display generally develop relatively late, when the animal is mature, for attracting mates," he added. "Their appearance here is at the wrong stage—it's really bizarre."

Similicaudipteryx's odd changes suggest that early birds and feathered dinosaurs experimented with a diversity of feather types and a variety of ways to use them, "which only later stabilized to the more conservative system we see now with modern birds," Xu said.

"There were very, very strange structures in the history of feathers."


The feathered dinosaurs are described in this week's issue of the journal Nature

Source