Saturday, December 31, 2011
Tuesday, December 27, 2011
Dino-Chicken???
Dino-Chicken: Wacky But Serious Science Idea of 2011
Stephanie Pappas, LiveScience Senior Writer
Date: 27 December 2011
SHARE
|
| Evolution in reverse: Could this chicken become a dinosaur? CREDIT: sanddebeautheil, Shutterstock |
But Horner's newest idea takes iconoclasm to a new level. He wants, in short, to hatch a dinosaur.
Or something very much like one, at least. Horner, who served as a technical advisor for the "Jurassic Park" movies, has no illusions that the technique in that movie — extracting dino DNA from mosquitoes in amber — would work. DNA degrades too quickly, for one thing. Dinosaur DNA has proved impossible to extract from actual dinosaur bones, never mind blood-sucking insects.
"If you actually had a piece of amber and it had an insect in it, and you drilled into it, and you got something out of that insect and you cloned it, and you did it over and over and over again, you'd have a room full of mosquitoes," Horner said in a February 2011 TED Talk in Long Beach, Calif. TED, or Technology, Entertainment and Design, is a nonprofit focusing on "ideas worth spreading."
Enough atavisms have been discovered in birds to make the idea of "reverse-engineering" a dinosaur out of, say, a chicken possible, Horner says. You wouldn't be adding anything to the bird to make it more dinosaurlike; all the ingredients are in its DNA. Horner's goal is to figure out how to wake up those ingredients.
LiveScience talked with Horner about his "chickenosaurus" plan and what sort of dinosaur he'd like to keep as a pet.
LiveScience: What was the genesis of this chickenosaurus idea?
Horner: Knowing that birds descended from dinosaurs and knowing the changes that occur from dinosaurs to birds, we know that the changes that did occur occurred because of genetics.
A friend of mine, Hans Larsson at McGill University, was studying some of these changes and looking into how it was that dinosaurs lost their tails in the transformation from dinosaurs to birds. They also transformed their arms from a hand and an arm to a wing. I got to thinking, if he discovered the genes that were responsible for both of those transformations, we could just simply reverse evolution and reactivate the tail, and possibly make a hand back out of the wing.
And then what we would have by doing those two things, you'd actually take a bird and turn it into an animal that looked a lot like one of the meat-eating dinosaurs. It seemed like a good idea.
LiveScience: What kind of animal would chickenosaurus be?
Horner: It's still a chicken. It's a modified chicken. You'd really have to mess with the DNA to make it something different.
The most important thing is that you cannot activate an ancestral characteristic unless the animal has ancestors. So if we can do this, it definitely shows that evolution works.
LiveScience: You've mentioned in the past that you see this dino-chicken as a teaching tool to help people understand evolution. Do you see that working?
Horner: Of course. You bet. There are people who are misinformed, and there are people who are uninformed [about the validity of evolution]. If people are uninformed, this will probably get through to them. If they've been misinformed and don't mind being misinformed, then they probably will continue to be misinformed.
LiveScience: Either way, it'd be a pretty awesome thing to take into a classroom.
Horner: Yes, it would. Exactly.
LiveScience: Starting with a chicken, how close could we really get to what a dinosaur looked like?
Horner: We're working with an animal that has all the right stuff. It's more about subtle changes, adding a tail or fixing a hand or possibly adding teeth, what we would think of as being relatively simple changes rather than messing with physiology or something like that.
A bird is really a dinosaur, so we're pretty sure that the breathing apparatus of a bird evolved from the breathing apparatus of a dinosaur, and is therefore completely different than a mammal. The physiology of a bird is evolved from a dinosaur and not from a mammal, so it's not like we're trying to take a mammal and turn it into a dinosaur.
LiveScience: Would chickenosaurus teach us anything about dinosaurs we can't learn from fossils?
Horner: It's not really about understanding dinosaurs at all. Once we learn what certain genes do and how to turn them on and turn them off, then we have great potential of solving some medical mysteries. There are a lot of ways to think about this, but it's not really about dinosaurs other than solving Hans Larsson's problem of figuring out how birds lost their tails. [Tales of 10 Vestigial Limbs]
LiveScience: What do you see as the biggest challenge of making chickenosaurus happen?
Horner: The biggest challenge, first off, is to find the genes. We know that in the development of a tail, there are a variety of things that have to happen, so there are a couple of ways to possibly go about this.
One, as we know, when a chicken embryo is developing in the egg, just like basically all animals, the embryo actually for a time has a tail and then the trail re-absorbs. So if we could find the gene that re-absorbs the tail and not allow that gene to turn on then we could potentially hatch a chicken with a tail.
The other method would be simply to go in and discover what Hox genes [the genes that determine the structure of an organism] might be responsible for actually adding tail vertebrae, and then to see if we could add some, either by manipulating the Hox genes or by using temperature. There have been some experiments done showing that adding heat will add a vertebra here or there.
LiveScience: Where are you in this process now?
Horner: Right now, mostly I'm looking for a postdoctoral researcher. An adventurous postdoc who knows a lot about developmental biology and a little bit about birds and has done some work about chickens to work in our lab here in Bozeman.
Me, I just go through the literature, looking for anything that might give me a clue as to what genes might be responsible for tail absorption or tail growth or something that might help me with hands.
LiveScience: The comparisons to "Jurassic Park" are easy to make, but have you ever seen the movie "The Birds?" Do we really want chickens with extra teeth and claws running around?
Horner: You can't really compare it to either movie. First off, you can go out in the Serengeti and there are all kinds of animals that will eat you, but if you're driving around in your Jeep, you're just fine. The lions and cheetahs and leopards are not going to try to get into your Jeep when there are plenty of plant-eaters out there to eat that aren't inside of a metal cage.
That's the funny thing about "Jurassic Park," right? All these dinosaurs want to eat people no matter how hard they are to get.
So we don't have to worry about "Jurassic Park," because that's just fiction. Animals don't act that way. They're not vengeful. And birds aren't vengeful either.
LiveScience: So if you could bring a dinosaur back — the real thing, not a modified chicken — what species would you choose?
Horner: A little one. A little plant-eater.
LiveScience: No T. rex for you?
Horner: Would you make something that would turn around and eat you? Sixth-graders would do that, but I'd just as soon make something that wouldn't eat me. And you could have it as a pet without worrying about it eating the rest of your pets.
source
Saturday, December 24, 2011
Do penguins communicate under water?
Do penguins communicate under water?
Written by Chris Thomas
Friday, 23 December 2011
“Very little is known about underwater acoustic communication in birds so any findings are important.”—Dr Parsons. Flickr: Andy Field
While penguins can be noisy on land, Dr Parsons says research into the sounds they make, if any, underwater has been extremely limited.
“Given some species of penguins spend significant time underwater and dive to depths where visual communication is reduced, it’s feasible that sound provides an alternative source of communication,” Dr Parsons says.
“The reasons behind any communication could be identifying, locating and catching food, warning signals, exploration, socialising and being antagonistic—but at the moment this is speculation.”
As part of his research Dr Parsons placed underwater noise loggers that include a hydrophone or underwater microphone, hard drive and battery pack, in Perth Zoo’s fairy penguin (Eudyptula minor novaehollandiae) enclosure.
The devices recorded all noise for nine out of every 15 minutes.
“If the penguins produce any sounds underwater we will be able to record them,” Dr Parsons says.
“From there, we would be able to investigate whether these sounds are used to communicate between the penguins or if they serve some other function (involuntary noise).
“Very little is known about underwater acoustic communication in birds so any findings are important.”
Dr Parsons says his research is in a controlled zoo environment and communication in the wild may be different.
Environmental noise could also affect penguin sounds and its perception underwater.
“There’s a lot of possible ways ambient, whether a biotic or man-made, noise can affect the sound production, transmission and reception,” he says.
“These can range from a behavioral change in the penguins with a disturbance causing movement away from the noise source and a reduced production of sound by penguins.”
“There’s also the masking of calls—ambient noise at the same frequency as any penguin calls will reduce the range at which a recipient can detect a call, or possibly the sound of an approaching predator.
“Particularly intense signals may cause temporary or permanent damage to the hearing.”
Perth Zoo’s penguin colony has been transferred to Melbourne Zoo while renovations take place and is due back before Christmas.
“What I am hoping to do is re-record when the penguins return from Melbourne and they re-acquaint themselves with their environment,” Dr Parsons says,
“Then we might hear some communication.”
source
Friday, December 16, 2011
Dinosaurs With Killer Claws Yield New Theory About Evolution of Flight
ScienceDaily (Dec. 14, 2011) — New research from Montana State University's Museum of the Rockies has revealed how dinosaurs like Velociraptor and Deinonychus used their famous killer claws, leading to a new hypothesis on the evolution of flight in birds.
"This study is a real game-changer," said lead author Fowler. "It completely overhauls our perception of these little predatory dinosaurs, changing the way we think about their ecology and evolution."
The study focuses on dromaeosaurids; a group of small predatory dinosaurs that include the famous Velociraptor and its larger relative, Deinonychus. Dromaeosaurids are closely related to birds, and are most famous for possessing an enlarged sickle-claw on digit two (inside toe) of the foot. Previous researchers suggested that this claw was used to slash at prey, or help climb up their hides, but the new study proposes a different behavior.
"Modern hawks and eagles possess a similar enlarged claw on their digit 2's, something that hadn't been noted before we published on it back in 2009," Fowler said. "We showed that the enlarged D-2 claws are used as anchors, latching into the prey, preventing their escape. We interpret the sickle claw of dromaeosaurids as having evolved to do the same thing: latching in, and holding on."
As in modern birds of prey, precise use of the claw is related to relative prey size.
"This strategy is only really needed for prey that are about the same size as the predator; large enough that they might struggle and escape from the feet," Fowler said. "Smaller prey are just squeezed to death, but with large prey all the predator can do is hold on and stop it from escaping, then basically just eat it alive. Dromaeosaurs lack any obvious adaptations for dispatching their victims, so just like hawks and eagles, they probably ate their prey alive too."
Other features of bird of prey feet gave clues as to the functional anatomy of their ancient relatives; toe proportions of dromaeosaurids seemed more suited for grasping than running, and the metatarsus (bones between the ankles and the toes) is more adapted for strength than speed.
"Unlike humans, most dinosaurs and birds only walk on their toes, so the metatarsus forms part of the leg itself," Fowler said. "A long metatarsus lets you take bigger strides to run faster; but in dromaeosaurids, the metatarsus is very short, which is odd."
Fowler thinks that this indicates that Velociraptor and its kin were adapted for a strategy other than simply running after prey.
"When we look at modern birds of prey, a relatively short metatarsus is one feature that gives the bird additional strength in its feet," Fowler continued. "Velociraptor and Deinonychus also have a very short, stout metatarsus, suggesting that they had great strength but wouldn't have been very fast runners."
The ecological implications become especially interesting when dromaeosaurids are contrasted with their closest relatives: a very similar group of small carnivorous dinosaurs called troodontids, Fowler said.
"Troodontids and dromaeosaurids started out looking very similar, but over about 60 million years they evolved in opposite directions, adapting to different niches," Fowler said. "Dromaeosaurids evolved towards stronger, slower feet; suggesting a stealthy ambush predatory strategy, adapted for relatively large prey. By contrast, troodontids evolved a longer metatarsus for speed and a more precise, but weaker grip, suggesting they were swift but probably took relatively smaller prey."
The study also has implications for the next closest relatives of troodontids and dromaeosaurids: birds. An important step in the origin of modern birds was the evolution of the perching foot.
"A grasping foot is present in the closest relatives of birds, but also in the earliest birds like Archaeopteryx," Fowler said. "We suggest that this originally evolved for predation, but would also have been available for use in perching. This is what we call 'exaptation:' a structure evolved originally for one purpose that can later be appropriated for a different use."
The new study proposes that a similar mechanism may be responsible for the evolution of flight.
"When a modern hawk has latched its enlarged claws into its prey, it can no longer use the feet for stabilization and positioning," Fowler said. "Instead the predator flaps its wings so that the prey stays underneath its feet, where it can be pinned down by the predator's bodyweight."
The researchers suggest that this 'stability flapping' uses less energy than flight, making it an intermediate flapping behavior that may be key to understanding how flight evolved.
"The predator's flapping just maintains its position, and does not need to be as powerful or vigorous as full flight would require. Get on top, stay on top; it's not trying to fly away," Fowler said. "We see fully formed wings in exquisitely preserved dromaeosaurid fossils, and from biomechanical studies we can show that they were also able to perform a rudimentary flapping stroke. Most researchers think that they weren't powerful enough to fly; we propose that the less demanding stability flapping would be a viable use for such a wing, and this behavior would be consistent with the unusual adaptations of the feet."
Another group of researchers has proposed that understanding flapping behaviors is key to understanding the evolution of flight, a view with which Fowler agrees.
"If we look at modern birds, we see flapping being used for all sorts of behaviors outside of flight. In our paper, we are formally proposing the 'flapping first' model: where flapping evolved for other behaviors first, and was only later exapted for flight by birds."
The researchers believe their new ideas will open multiple new lines of investigation into dinosaur paleobiology, and the evolution of novel anatomical structures.
"As with other research conducted at the Jack Horner paleo lab, we're looking at old paleontological questions with a fresh perspective, taking a different angle," Fowler said. "Just as you have to get beyond the idea that feet are used just for walking, so we are coming to realize that many unusual structures in modern animals originally evolved for quite different purposes. Revealing the selection pathways that mold and produce these structures helps us to better understand the major evolutionary transitions that shaped life on this planet."
Story Source:
The above story is reprinted from materials provided by Montana State University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Denver W. Fowler, Elizabeth A. Freedman, John B. Scannella, Robert E. Kambic. The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE, 2011; 6 (12): e28964 DOI: 10.1371/journal.pone.0028964
Montana State University (2011, December 14). Dinosaurs with killer claws yield new theory about evolution of flight. ScienceDaily. Retrieved December 16, 2011, from http://www.sciencedaily.com /releases/2011/12/111214171541.htm
Thursday, December 15, 2011
100 years on, Antarctic science going strong
A NASA aircraft, part of the agency's
IceBridge mission, banks over an ice shelf jutting out from western
Antarctica during an October 2011 data-gathering flight.
Yet in an ironic twist, some might argue that it is the runner-up in the grueling contest whose legacy has proved more lasting.
British explorer Robert Falcon Scott, who reached the pole a month after Amundsen, died on his return march, unable to escape the tightening noose of the Antarctic winter. And although his oft-maligned tactics proved, in part, to be his undoing, Scott's insistence on bringing scientists on his expedition — at great cost to himself — helped spark a tradition of scientific inquiry in Antarctica that endures to this day, according to Ross MacPhee, curator at the American Museum of Natural History in New York, and author of the book, "Race to The End: Amundsen, Scott, and the Attainment of the South Pole" (Sterling Innovation, 2010).
"Every scientist working in Antarctica today owes Scott something," MacPhee told OurAmazingPlanet in September.
Science is now one of the primary drivers of human activity on the continent.
Each year, when the perpetual daylight of austral summer begins, droves of scientists descend on Antarctica to study its biology, drill deep into its ice, and send airplanes soaring overhead to image what lies underneath its glaciers.
Nearly 30 countries operate more than 80 research stations around the continent, according to 2009 numbers from the Council of Managers of National Antarctic Programs.
A flurry of work is now under way on and around the continent.
Courtesy of Charles Leski, Leski Auctions.
Charismatic fauna
Some scientists come to study the unique crowds of marine life that gather near the nutrient-rich waters off the Antarctic coast in the comparatively balmy summer. Penguins may be the most beloved of the local animal pantheon, but studying these birds is nothing like a Disney movie.
"Penguins are not cuddly at all. They're really very strong and very feisty, and they don't like to be picked up, which we try not to do," said David Ainley, a marine ecologist who has been studying Adélie penguins in Antarctica since the late 1960s.
For decades, Ainley, now with the California-based ecological consulting firm H.T. Harvey & Associates, has researched why penguin populations are changing; some colonies have grown, others have shrunk. He said he's interested in answering a very basic question about life on our planet — how do animals cope with their environment? — and that penguins are the ideal research subject.
"They're fairly large so you can put instruments on them and record their behavior," Ainley told OurAmazingPlanet just hours before he boarded a plane headed south.
Dr. Robert Ricker, NOAA / NOS / ORR
In addition, he said, they're pretty easy to find. "Penguins are very visible," Ainley said. "In the Antarctic they don't have any place to hide. They don't live in burrows, and it's daylight all the time."
Biological time trip
While Ainley and his team spend their days on the rocky slopes of Antarctic islands, other scientists spend the austral summer on ships. David Barnes, with the British Antarctic Survey, spoke with OurAmazingPlanet from the RRS James Ross, a research vessel parked near the Antarctic Peninsula, the long finger of land that points toward South America.
Barnes said that his research focuses on trying to unlock the secrets of Antarctica's icy past, specifically how the reach of the massive West Antarctic Ice Sheet has changed from age to age. Scientists know it has been larger than it is now, and some suspect it has been smaller than it is now, but anything more exact is difficult to pin down.
"The problem is that every time there's an ice age it's wiped out everything — so we don't really know where the last ice sheet got to," Barnes said. But there is another way to peek into the Antarctic's past: "Where we can't get good signals from glaciology or geology, biology has a cunning way of stepping in," he said.
Eric Rignot, JPL
Barnes looks at the genetic makeup of sea creatures around western Antarctica to determine how long populations have been isolated from one another by the ice.
"Genetics preserve a connection between species and populations, so by looking around Antarctica at various depths we can get an idea of whether that area used to be underneath an ice sheet," Barnes said.
That information can, in turn, help scientists figure out how the West Antarctic Ice Sheet behaved in climates past, and how it might behave in our warming world.
Ice life
Still other scientists will spend the austral summer living on the ice itself. Robert Bindschadler, a glaciologist and scientist emeritus with NASA, along with a small team of researchers, will spend six weeks sleeping in small tents on a floating plain of ice — the Pine Island Glacier ice shelf — the outlet of one of the largest and fastest moving glaciers in Antarctica.
Ice shelves, which ring the continent, appear to be a key player in the increasing and alarming rate at which glaciers in the West Antarctic Ice Sheet are melting and raising sea levels in recent years, Bindschadler said. But getting direct observations of how this is happening is a challenge. Satellite imaging and data provide some details, but the continent is remote, and its long, brutal winter permits scientists to work there for only about three months a year, [ Stunning Photos of Antarctic Ice ]
Observations indicate that comparatively warm ocean water is lapping away at the ice shelves, which, as they weaken, allow glaciers to slide into the sea at a faster and faster clip — yet the direct mechanisms remain hidden from view.
"Satellites have taken us really far, but they can't give us the answers to what's going on underneath," Bindschadler said. To that end, his team will spend its days drilling several holes through nearly a third of a mile (500 meters) of ice to drop sensors into the sea below to measure variations in temperature and currents.
Some scientists conduct their research from the air, working aboard planes equipped with imaging technology that can peer beneath the ice. NASA's IceBridge project focuses on the western half of the continent, while other international collaborations focus on the far larger yet more stable eastern half.
Ice work if you can get it
Other research must be done on the ground. Scientists are drilling deep into the ice to collect signatures of past climate trapped inside, or looking for microbes that dwell in it. The race to drill down to the more than 200 freshwater lakes that pepper the continent is another tantalizing quest..
Some researchers work in Antarctica because the frigid continent,
free of a native human population or meddling flora and fauna, provides a
kind of natural laboratory. British explorer Robert Falcon Scott, who reached the pole a month after Amundsen, died on his return march, unable to escape the tightening noose of the Antarctic winter. And although his oft-maligned tactics proved, in part, to be his undoing, Scott's insistence on bringing scientists on his expedition — at great cost to himself — helped spark a tradition of scientific inquiry in Antarctica that endures to this day, according to Ross MacPhee, curator at the American Museum of Natural History in New York, and author of the book, "Race to The End: Amundsen, Scott, and the Attainment of the South Pole" (Sterling Innovation, 2010).
"Every scientist working in Antarctica today owes Scott something," MacPhee told OurAmazingPlanet in September.
Science is now one of the primary drivers of human activity on the continent.
Each year, when the perpetual daylight of austral summer begins, droves of scientists descend on Antarctica to study its biology, drill deep into its ice, and send airplanes soaring overhead to image what lies underneath its glaciers.
Nearly 30 countries operate more than 80 research stations around the continent, according to 2009 numbers from the Council of Managers of National Antarctic Programs.
A flurry of work is now under way on and around the continent.
Robert Falcon Scott in the expedition's well-stocked hut.
Some scientists come to study the unique crowds of marine life that gather near the nutrient-rich waters off the Antarctic coast in the comparatively balmy summer. Penguins may be the most beloved of the local animal pantheon, but studying these birds is nothing like a Disney movie.
"Penguins are not cuddly at all. They're really very strong and very feisty, and they don't like to be picked up, which we try not to do," said David Ainley, a marine ecologist who has been studying Adélie penguins in Antarctica since the late 1960s.
For decades, Ainley, now with the California-based ecological consulting firm H.T. Harvey & Associates, has researched why penguin populations are changing; some colonies have grown, others have shrunk. He said he's interested in answering a very basic question about life on our planet — how do animals cope with their environment? — and that penguins are the ideal research subject.
"They're fairly large so you can put instruments on them and record their behavior," Ainley told OurAmazingPlanet just hours before he boarded a plane headed south.
Don't ask these guys to tap dance. Adelie penguins in Antarctica.
In addition, he said, they're pretty easy to find. "Penguins are very visible," Ainley said. "In the Antarctic they don't have any place to hide. They don't live in burrows, and it's daylight all the time."
Biological time trip
While Ainley and his team spend their days on the rocky slopes of Antarctic islands, other scientists spend the austral summer on ships. David Barnes, with the British Antarctic Survey, spoke with OurAmazingPlanet from the RRS James Ross, a research vessel parked near the Antarctic Peninsula, the long finger of land that points toward South America.
Barnes said that his research focuses on trying to unlock the secrets of Antarctica's icy past, specifically how the reach of the massive West Antarctic Ice Sheet has changed from age to age. Scientists know it has been larger than it is now, and some suspect it has been smaller than it is now, but anything more exact is difficult to pin down.
"The problem is that every time there's an ice age it's wiped out everything — so we don't really know where the last ice sheet got to," Barnes said. But there is another way to peek into the Antarctic's past: "Where we can't get good signals from glaciology or geology, biology has a cunning way of stepping in," he said.
This is an aerial, close-up view of the floating section and ice front of Pine Island glacier, November 2002.
"Genetics preserve a connection between species and populations, so by looking around Antarctica at various depths we can get an idea of whether that area used to be underneath an ice sheet," Barnes said.
That information can, in turn, help scientists figure out how the West Antarctic Ice Sheet behaved in climates past, and how it might behave in our warming world.
Ice life
Still other scientists will spend the austral summer living on the ice itself. Robert Bindschadler, a glaciologist and scientist emeritus with NASA, along with a small team of researchers, will spend six weeks sleeping in small tents on a floating plain of ice — the Pine Island Glacier ice shelf — the outlet of one of the largest and fastest moving glaciers in Antarctica.
Ice shelves, which ring the continent, appear to be a key player in the increasing and alarming rate at which glaciers in the West Antarctic Ice Sheet are melting and raising sea levels in recent years, Bindschadler said. But getting direct observations of how this is happening is a challenge. Satellite imaging and data provide some details, but the continent is remote, and its long, brutal winter permits scientists to work there for only about three months a year, [ Stunning Photos of Antarctic Ice ]
Observations indicate that comparatively warm ocean water is lapping away at the ice shelves, which, as they weaken, allow glaciers to slide into the sea at a faster and faster clip — yet the direct mechanisms remain hidden from view.
"Satellites have taken us really far, but they can't give us the answers to what's going on underneath," Bindschadler said. To that end, his team will spend its days drilling several holes through nearly a third of a mile (500 meters) of ice to drop sensors into the sea below to measure variations in temperature and currents.
Some scientists conduct their research from the air, working aboard planes equipped with imaging technology that can peer beneath the ice. NASA's IceBridge project focuses on the western half of the continent, while other international collaborations focus on the far larger yet more stable eastern half.
Ice work if you can get it
Other research must be done on the ground. Scientists are drilling deep into the ice to collect signatures of past climate trapped inside, or looking for microbes that dwell in it. The race to drill down to the more than 200 freshwater lakes that pepper the continent is another tantalizing quest..
"In most ecosystems you have plants all over the place, and they do a lot of things to complicate the system," said Byron Adams, a professor at Brigham Young University who studies the nematodes and other tiny creatures that are found in the few patches of ice-free soil in the Antarctic.
Flags fly outside McMurdo Station, one of three United States research stations in Antarctica and the largest.
At about 1.5 times the size of the United States, Antarctica has plenty of scientific real estate to go around.
At the heart of much of the research is the question of how the continent's ice is responding to climate change. Antarctica is home to some of the most dramatic effects of climate change seen anywhere on Earth, from melting glaciers to increasing winds to warming temperatures. The Antarctic Peninsula has warmed several times faster than the global average rate.
"We're asking really fundamental questions about how ecosystems respond to a changing climate, and ultimately the goal is to be able to make predictions about this," Adams told OurAmazingPlanet.
Despite the challenges — bone-chilling winds, constant sunlight, extreme isolation and ever-changing weather — many scientists said working in Antarctica is worth the hardship and the long hours spent packing as much work into an expedition as possible. Although it's not for everyone, they cautioned, the work can be deeply satisfying, breeding a sense of camaraderie that can last a lifetime.
"When you're out in the deep field, and you're only living with what you brought, and the plane turns and leaves, that's the Antarctica I prefer," Bindschadler said. "You really are in a different world."
source
Seabirds: Climate Differences Have Less Impact On Transmission of Blood Parasites Than Expected
ScienceDaily (Dec. 12, 2011)
— Seabirds often live in large colonies in very confined spaces.
Parasites, such as fleas and ticks, take advantage of this ideal habitat
with its rich supply of nutrition. As a result, they can transmit blood
parasites like avian malaria to the birds. Scientists from the
Max Planck Institute for Ornithology in Radolfzell and a team of
international colleagues have investigated whether this affects all
seabirds equally, and whether climate conditions, the habitat or
particular living conditions influence infection with avian malaria.
They discovered that most seabirds are free of malaria parasites;
however, some groups, especially frigatebirds, are particularly common
hosts to malaria parasites.
Although there is a link between warmer temperatures and increased
rates of infection, not all tropical seabirds are infected. The risk of
infection within a habitat increases for species with longer fledgling
periods and specific types of breeding grounds.
Seabirds exist in locations as varied as the Antarctic and tropical oceans. However, they all need land for breeding grounds. In order to protect themselves against predators or due to a lack of suitable breeding places, they often form large dense colonies. As a result, they provide blood suckers like fleas, ticks and bird lice -- wingless insects which live in the plumage and feed on the birds' feathers and blood -- with a plentiful supply of food and a habitat. Therefore, these insects can arise in large numbers in such colonies. These small pests also survive well in cold climates such as that found in the Subantarctic, and are not particularly specialised in their choice of food, something the researchers know from their own painful experience.
Other blood-sucking insects, like mosquitoes, are present mainly in warmer climates, as found in the tropical breeding grounds. Because mosquitoes are among the main transmitters of the Plasmodium genus of avian malaria, the researchers from the Max Planck Institute for Ornithology and their colleagues from Spain, France, Mexico and the US investigated whether infections of avian malaria differed in seabirds from cold and warm marine areas. To do this, they analysed blood samples from seabirds from different regions for parasitic infections using genetic methods.
"We were surprised that the climate differences had less impact on the transmission of blood parasites than expected," says Petra Quillfeldt. "More vectors live in warmer climates; therefore, we would have expected to find a higher rate of infection in tropical locations. We discovered, however, that different species living on the same island under the same climate conditions can display very different rates of infection." The researchers defined several seabird groups that regularly carry malaria parasites. Frigatebirds were found to be particularly affected here, as all five species of this tropical seabird family are frequently infected.
"Of five seabird species present in the seabird community on Christmas Island in the tropical Indian Ocean, only the Christmas Island frigatebirds were found to be malaria hosts. Over half of the island's frigatebirds were affected and, moreover, with three genetically different malaria lines of the subgenera Haemoproteus and Parahaemoproteus, one of which was a completely new strain. As opposed to this, tropical birds and three species of gannet on the same island were not infected at all," explains Petra Quillfeldt.
Furthermore, the scientists have failed to find any blood parasite infections in other seabird groups, such as skuas and auks. Their research has led to the conclusion that the likelihood of infection depends, among other things, on the lifestyle of the birds: species with longer fledgling periods and hole-nesters are particularly severely affected.
This is the first study of this kind to examine seabirds in all climate zones. It has shown that different factors can influence infection with malaria parasites. The study also raised new questions: The researchers would now like to gain a better understanding of the life cycles of the malaria parasites and their transmitters, as well as discover which mechanisms are responsible for susceptibility to infection among the different species.
Story Source:
The above story is reprinted from materials provided by Max-Planck-Gesellschaft.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal References:
- Petra Quillfeldt, Elena Arriero, Javier MartÃnez, Juan F Masello, Santiago Merino. Prevalence of blood parasites in seabirds - a review. Frontiers in Zoology, 2011; 8 (1): 26 DOI: 10.1186/1742-9994-8-26
- Merino, S., Hennicke, J., MartÃnez, J., Ludynia, K., Masello, J.F. & Quillfeldt, P. Infection by Haemoproteus parasites in four species of frigatebirds and description of Haemoproteus (Parahaemoproteus) valkiÅ«nasi sp. nov. (Haemosporida, Haemoproteidae). Journal of Parasitology, 2011 Oct 12
Max-Planck-Gesellschaft (2011, December
12). Seabirds: Climate differences have less impact on transmission of
blood parasites than expected. ScienceDaily. Retrieved December 15, 2011, from http://www.sciencedaily.com /releases/2011/12/111212092655.htm
Wednesday, December 14, 2011
Antarctic study digs for clues to penguin past
By James Borrowdale
Wednesday Dec 14, 2011
Adelie penguins live in the coldest environment on earth.
Experts warn the effects of a warming climate could affect the small ecological niche in which Adelie penguins reside.
Scientists from the University of Auckland and Italy's University of Pisa are in Antarctica to search for clues about Adelie penguins' evolutionary past, and what this reveals about how they will respond to climate change.
Professor Carlo Baroni, professor of geomorphology at the University of Pisa, said penguins lived in the coldest environment on earth and if the temperature warmed, penguins couldn't migrate to a colder climate.
"If global warming increases and affects the Antarctic regions, penguins have no other place to go, so they must adapt or die."
The team left Scott Base this week for a month of collecting samples from two penguin rookeries. Over many years of habitation Adelie penguins leave layers of accumulated bones, eggshells, feathers, nests, and guano. This presents scientists with the opportunity to dig through the levels and gather DNA from long-dead penguins.
Professor Baroni, now on his 14th trip to Antarctica, said his team had previously uncovered samples as old as 40,000 years.
"We are at the limits of the capability of radiocarbon dating."
Auckland University's Yvette Wharton said the limited ecological niche of Adelie penguins made them excellent subjects for studying adaptive evolution. As their niche changed, she said, the penguins would have to change with it.
"As we are getting climate change occurring there is going to be quite a specific effect on their potential ecological niche. We're squishing them."
She said they would learn of past climatic changes, how the colony sizes had changed, and how the penguins had evolved to meet these new conditions.
"You can then use that as a model to see the types of things that might happen to an organism with environmental changes."
ADELIE PENGUINS
* Males and females come on land for just a few months each summer to breed and raise their chicks - a task mastered by "tag-team parenting" in minding the egg.
* Males arrive first to find the best spot and build a nest. When the females arrive, the males serenade their prospective mates with a sound described as a cross between a donkey and a stalled car.
* Females look for the fattest male they can find, as their partner must spend the first two weeks sitting on the eggs without any chance to go in search of food.
source
Friday, December 9, 2011
How penguins 'time' a deep dive
The penguins beat their wings an average of 237 times on each dive
Emperor penguins "time" their dives by the number of flaps they can manage with their wings.
It aimed to show how the birds reached the "decision" that it was time to stop feeding and return to the surface to breathe.
Tracking the birds revealed that they flapped their wings, on average, 237 times on each dive.
The study was led by Dr Kozue Shiomi, from the University of Tokyo, Japan.
Dr Shiomi and his team think that the penguins' decision to end their foraging dive and return to the surface is constrained by how much power their muscles can produce after every pre-dive breath. This "flying" motion propels the birds forwards, allowing them to swim quickly through the water, gulping fish.
Using data collected from diving penguins on previous field trips, the team analysed the patterns of more than 15,000 penguin dives.
They studied 10 free-ranging birds and three birds that were foraging through a hole in the ice.
EMPEROR PENGUIN FACTS
- Emperor penguins are the largest species of penguin, standing at over one metre tall and weighing an average of 40kg
- In the bitter cold, males and females choose mates relatively quickly, pairing off and "flirting" with special neck-stretching displays
- The males incubate eggs through the fierce Antarctic winter while females feed themselves up to provide for their chicks in the spring
Timing the penguins' dives
revealed that free-ranging birds began their final ascent to the surface
about 5.7 minutes into their dive. But penguins diving through the ice
hole often dived for longer before performing a U-turn and returning up
through the same ice hole.
"We suggest", the team concluded in their paper, "that the decision [to return] was constrained not by elapsed time, but by the number of strokes and, thus, perhaps cumulative muscle work."
source
Friday, November 4, 2011
The Realm of the Red Penguin: Peru's Dead Sea of Fossils
A researcher for Peru's Natural History
Museum rests next to the fossilized skeleton of an ancient seal in the
Ocucaje Desert in Ica, Peru.
Moises Saman / The New York Times / Redux
Roberto Penny Cabrera is a former officer in the Peruvian Navy and still loves the sea, but the ocean that now captures his attention is not wet. In fact, it has been one of the driest places on earth for millions of years.
Penny, 55, is a self-trained authority on a strip of Peru's coastal desert in Ica, 180 miles south of the capital, Lima. The desert was once a shallow sea with abundant marine life, but that ended when the Andes Mountains surged upward. The resulting cataclysm created what is the world's largest cemetery of marine fossils, many poking out of the white sand.
What sets this stretch of Ica desert apart from similar areas is the preservation of more than bone. The discovery last year of a 5-ft.-tall penguin included the first evidence of preserved scales and feathers, letting experts know that the big bird was red instead of black and white like today's smaller version. It died about 36 million years ago. Also recently discovered in this windswept, rolling desert was the skull of a giant whale, dubbed Leviathan melvillei in honor of Moby Dick's creator. The whale stretched nearly 60 ft. and is believed to have fed on other whales. Its jaw is similar to that of modern-day sharks, with rows of top and bottom teeth.
Penny, who calls himself a "finder," said, "It is amazing to see what the ocean was like millions of years ago. I am not a paleontologist, but you don't have to have a degree to know that what we have here can tell us how the ocean worked." He may not have a title, but Penny has the desert in his blood. One of his distant relatives founded the city of Ica in the mid-16th century, and the family has been there since. He first wandered into the desert as a boy, when his parents would take him to a nearby oasis, Huacachina. "We would go to Huacachina, but I was interested in the surrounding desert. It is where I feel free," he said. Those early family excursions turned into a lifelong obsession with Peru's dead sea
Penny's quest today is to protect the desert, not only safeguarding marine fossils but also burial grounds of Nazca and Paracas cultures, which date back more than 2,000 years, and the area's stunning landscape of ancient seabeds and towering, windblown dunes.
It is an uphill battle.
The rolling dunes around Ocucaje, a small town that serves as a gateway to the desert and lends the arid strip its name, are strewn with skeletons tossed aside by looters digging through burial grounds in search of pottery and world-renowned Paracas textiles. Fossil hunters have chipped away at whale skeletons and decimated shell beds looking for the prized teeth of the megalodon (literally "giant tooth"), giant sharks that once prowled here. "The principal problem in Ocucaje right now is the illegal collection of fossils for scientific or commercial purposes," said José ApolÃn, a specialist at Peru's Culture Ministry, which just celebrated its first anniversary.
But there is also a problem with control. ApolÃn, who is technically a biologist, is the only paleontological specialist in the ministry, and he is in the unit in charge of preventing theft and controlling items that are seized. In 2010, his first year on the job, police at the international airport in Lima seized 1,962 cultural items protected by law. Fossils accounted for 1,712 of the items seized.
Even if there were many more employees like ApolÃn, the law protecting cultural heritage is vague when it comes to fossils. "Fossils are in a kind of legal limbo in Peru. There are gaps in the law because there are people who do not want to include fossils as cultural heritage, because they have not been made by human hand," said Blanca Alva, director of the prevention office.
The ministry has an archaeological division, but there is no paleontology division. Paleontology falls to a unit of the Energy and Mines Ministry. Still, the Culture Ministry is getting ready in the next few weeks to declare Peru's first protected paleontological site. The area, known as the Inga Bridge, is a small site located just outside Lima. ApolÃn said it will be the first of its kind among 13,000 protected sites nationwide.
While Penny bristles with anger at fossil hunters digging through the desert to pull out what they can sell, he gets even more worked up about authorities, who he says have done nothing to stop it. He says their inaction makes them complicit. Penny gets madder still when he is lumped in with the fossil traffickers — ApolÃn points to video of Penny handling fossils — because of a small, bizarre collection, including shark teeth, in a single room he calls home in the old family mansion that has seen much better days. Under Peruvian law, the country's treasures, whether fossils or golden objects looted from tombs, can be held in personal collections. It is only illegal to remove them from the country.
"I have never sold a fossil, and what I have, I have found on the desert floor," he said. "There are amazing things out there, but if I tell anyone, they will be lost." Driving a specially equipped truck that lets him roam the desert, Penny is careful to cover his tracks. He continuously doubles back and drives in circles at times to throw others off his trail, fearful that fossil scavengers will follow him to his sacred spots.
Regional tourism authorities would like to promote the desert but worry that a flood of people could mean rampant destruction. "There is an entire desert with a massive amount of fossils. The desert is an attraction that we cannot promote, because large fossils are being taken away and no one is doing anything to stop it," said Elard Roca of the government's local tourism bureau.
Penny's solution is to declare the desert a protected area, but conservationists say the move would be impractical. Pedro Solano, who runs the conservation program for the Peruvian Environmental Law Society, one of the country's leading environmental groups, said that while there are important fossilized remains in the desert, "it would be wrong to say the entire area holds fossils and should be set aside. These kinds of generalization usually cause problems," he said.
Trying to guard the area is also nearly impossible because of its size. The area that contains fossil remains is about 180 miles long and 40 miles wide. The giant penguin was found in the northern reaches, while the whale skeletons are found from Ocucaje south. The Ocucaje stretch is about one-quarter of the total area. Solano said the goal for the desert "should not be to keep people out but manage the spaces for education and research to demonstrate its value as a resource." The Culture Ministry's ApolÃn said the best way to protect the area is "guaranteeing that fossils are not taken from the country. If we can improve control of fossils trafficking at the airport and ports, we would protect the site."
source
Sunday, October 30, 2011
Archaeopteryx was first bird after all
October 26, 2011
Enlarge
In a study published today in the journal Biology Letters,
Australian researchers say the feathered fossil is indeed of the first
known bird, despite another study earlier this year suggesting
otherwise.
Archaeopteryx had been considered for 150 years to be the first known bird since the first complete specimen was found in Germany in 1861, revealing a combination of reptilian and and bird features. But Chinese researchers asserted recently that a new and closely related fossil, Xiaotingia zhengi, was a bird-like dinosaur - therefore suggesting that Archaeopteryx was also a dinosaur.
However, the new study, led by Dr Michael Lee, of the South Australian Museum, used a more detailed analyis to show that Archaeopteryx was a bird.
"Archaeopteryx is iconic in palaeontology as the basal bird, however the plethora of discoveries of feathered dinosaurs in China, in particular, has progressively eroded the distinction of just what defines a bird," says one of the authors, Dr Trevor Worthy, a palaeontologist in the UNSW School of Biological, Earth and Environmental Sciences.
"This trend came to a head when Xaiotingia was analysed most recently and in the analysis presented Archaeopteryx was found to jump ship as it were from the birds to the dromaeosaurs.
"This sensational result was presented and attracted much publicity, but the very weak statistical support for this new relationship was not given due consideration.
"In our work, Mike Lee has shown quite clearly that methodology is highly significant and that before a paradigm is overturned data needs to be rigorously examined.
"Using a different analytical methodology than that usually used by morphologists, but one always used by analysts of molecular data, we found that Archaeopteryx remains the basal bird and does so with strong statistical support.
"This case demonstrates that multiple analysis methods should be used, each with concordant results before a paradigm breaking result is accepted. And it shows that Archaeopteryx remains the key to understanding the origin of birds."
More information: http://rsbl.royals … tent/current
Provided by University of New South Wales
source
Enlarge
Archaeopteryx fossil (Creative Commons - Wikipedia)
(PhysOrg.com) -- The crown of the famous
150-million-year-old Archaeopteryx fossil as the first bird has been
restored by a new evolutionary tree.
Archaeopteryx had been considered for 150 years to be the first known bird since the first complete specimen was found in Germany in 1861, revealing a combination of reptilian and and bird features. But Chinese researchers asserted recently that a new and closely related fossil, Xiaotingia zhengi, was a bird-like dinosaur - therefore suggesting that Archaeopteryx was also a dinosaur.
However, the new study, led by Dr Michael Lee, of the South Australian Museum, used a more detailed analyis to show that Archaeopteryx was a bird.
"Archaeopteryx is iconic in palaeontology as the basal bird, however the plethora of discoveries of feathered dinosaurs in China, in particular, has progressively eroded the distinction of just what defines a bird," says one of the authors, Dr Trevor Worthy, a palaeontologist in the UNSW School of Biological, Earth and Environmental Sciences.
"This trend came to a head when Xaiotingia was analysed most recently and in the analysis presented Archaeopteryx was found to jump ship as it were from the birds to the dromaeosaurs.
"This sensational result was presented and attracted much publicity, but the very weak statistical support for this new relationship was not given due consideration.
"In our work, Mike Lee has shown quite clearly that methodology is highly significant and that before a paradigm is overturned data needs to be rigorously examined.
"Using a different analytical methodology than that usually used by morphologists, but one always used by analysts of molecular data, we found that Archaeopteryx remains the basal bird and does so with strong statistical support.
"This case demonstrates that multiple analysis methods should be used, each with concordant results before a paradigm breaking result is accepted. And it shows that Archaeopteryx remains the key to understanding the origin of birds."
More information: http://rsbl.royals … tent/current
Provided by University of New South Wales
source
Monday, October 17, 2011
Which NZ coastal species really are native?
Prof Jon Waters takes a close look at a stuffed yellow-eyed
penguin at the Otago Museum. Photo: Peter McIntosh
Yellow-eyed penguins, for instance, apparently arrived in New Zealand only in the past 500 years, replacing a prehistoric penguin species, the waitaha, that was wiped out shortly after human settlement, he said.
One of his former Otago PhD students, Dr Sanne Boessenkool, undertook earlier research several years ago and discovered remains of the extinct waitaha penguin.
It is suggested that some yellow-eyed penguins made their way north from their native Auckland Islands and Campbell Island and later established themselves on the Otago Peninsula and elsewhere on the Otago coast after the waitaha penguin became extinct.
Many people would be surprised the yellow-eyed penguin may not have been living in Otago as long as previously believed, he said.
"We tend to think that things that are here now are things that have been here for a long time," Prof Waters said.
The kind of extinction-recolonisation events apparently involved with such penguins may be the rule rather than the exception in coastal New Zealand, including with sea-lions and little blue penguins, he said.
It was "great" to be able to pursue the research, after two earlier recent attempts to gain Marsden funding for the project had been unsuccessful.
The little blue penguins which had now established themselves on the Otago coast, after earlier being largely wiped out by humans, were in fact penguins from Australia.
They were different from endemic little blue penguins found elsewhere on the New Zealand mainland.
New Zealand sea lions found on the Otago coast were also not the same creatures that once previously existed there, but were apparently a replacement population from the subantarctic islands, researchers said.
Collaborators in the project are Prof Lisa Matisoo-Smith, of the Otago anatomy department, and Dr Paul Scofield, of the Canterbury Museum.
The researchers will use carbon dating and state-of-the-art DNA analysis of prehistoric bones to shed further light on the country's "dramatic biological history", and to conduct a biological audit of prehistoric New Zealand.
Archaeologists would be teaming up with geneticists, in order to "reveal exciting aspects of New Zealand's past - stories that were previously impossible to tell," he said.
Source
Wednesday, September 28, 2011
Pigeon 'Milk' Contains Antioxidants and Immune-Enhancing Proteins
Pigeon and chick. (Credit: Dr. Tamsyn Crow
ScienceDaily (Sep. 28, 2011)
— Production of crop milk, a secretion from the crops of parent birds,
is rare among birds and, apart from pigeons, is only found in flamingos
and male emperor penguins. Essential for the growth and development of
the young pigeon squab, pigeon 'milk' is produced by both parents from
fluid-filled cells lining the crop that are rich in fat and protein.
Researchers from CSIRO Livestock Industries and Deakin University, Australia, compared the global gene expression profiles of the crops of four 'lactating' and four 'non-lactating' female pigeons. As the pigeon genome has not yet been sequenced, they used a chicken microarray to find the genes involved. Genes predominantly over-expressed in 'lactating' birds were those involved in stimulating cell growth, producing antioxidants and in immune response. They also found genes associated with triglyceride fat production, suggesting the fat in the 'milk' is derived from the pigeon's liver.
Lead author, Meagan Gillespie, says, "It is possible that if antioxidant and immune proteins are present in pigeon 'milk', they are directly enhancing the immune system of the developing squab as well as protecting the parental crop tissue." She continues, "This study has provided a snap-shot view of some of the processes occurring when 'lactation' in the pigeon crop is well established. Due to the unusual nature of 'lactation' in the pigeon it would be interesting to investigate the early stages of the differentiation and development of the crop in preparation for 'milk' production to further ascertain gene expression patterns that characterize crop development and 'lactation' in the pigeon."
She concludes, "This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon 'milk' fulfills a similar function to mammalian milk."
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.
Journal Reference:
- Meagan J. Gillespie, Volker R. Haring, Kenneth A. McColl, Paul Monaghan, John A. Donald, Kevin R. Nicholas, Robert J. Moore, Tamsyn M. Crowley. Histological and global gene expression analysis of the 'lactating' pigeon crop. BMC Genomics, 2011; 12: 452 DOI: 10.1186/1471-2164-12-452
BioMed Central (2011, September 28). Pigeon 'milk' contains antioxidants and immune-enhancing proteins. ScienceDaily. Retrieved September 28, 2011, from http://www.sciencedaily.com /releases/2011/09/110919074253.htm
Tuesday, September 27, 2011
Feathered Friends Are Far from Bird-Brained When Building Nests
ScienceDaily (Sep. 26, 2011) — Nest-building is not just instinctive but is a skill that birds learn from experience, research suggests.
The researchers found that individual birds varied their technique from one nest to the next. They also saw that some birds build their nests from left to right, and others from right to left.
Also, as the birds gained more experience in building nests, they dropped blades of grass less often, implying that the art of nest building requires learning.
Researchers from the Universities of Edinburgh, St Andrews and Glasgow together with scientists from Botswana say their findings may help to explain how birds approach nest-building and whether they have the mental capacity to learn, or whether their skills are developed through repetition.
Researchers chose the colourful African bird because they build complex nests, which is potentially a sign of intelligence. More importantly, Weaver birds build many nests -- often dozens in a season, allowing the team to monitor differences in nests built by the same bird.
Dr Patrick Walsh of the University of Edinburgh's School of Biological Sciences, who took part in the study, said: "If birds built their nests according to a genetic template, you would expect all birds to build their nests the same way each time. However this was not the case. Southern Masked Weaver birds displayed strong variations in their approach, revealing a clear role for experience. Even for birds, practice makes perfect."
The research was published in the journal Behavioural Processes and was funded by the Leverhume Trust.
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Edinburgh, via EurekAlert!, a service of AAAS.
Journal Reference:
- Patrick T. Walsh, Mike Hansell, Wendy D. Borello, Susan D. Healy. Individuality in nest building: Do Southern Masked weaver (Ploceus velatus) males vary in their nest-building behaviour? Behavioural Processes, 2011; 88 (1): 1 DOI: 10.1016/j.beproc.2011.06.011
University of Edinburgh (2011, September 26). Feathered friends are far from bird-brained when building nests. ScienceDaily. Retrieved September 27, 2011, from http://www.sciencedaily.com /releases/2011/09/110925192704.htm
Thursday, September 22, 2011
Smells may help birds identify their relatives
Researchers at U Chicago and the Chicago Zoological Society found in an experiment at Brookfield Zoo that penguins can recognize the smell of familiar locations, something that may guide them back to their mates. The ability is useful as penguins live in large colonies but remain monogamous.
Photos by Jim Schulz/Chicago Zoological Society
Smells may help birds identify their relatives
William Harms
September 21, 2011
Birds may have a more highly developed sense of smell than researchers
previously thought, contend scholars who have found that penguins may
use smell to determine if they are related to a potential mate.
The research by the University of Chicago and the Chicago Zoological Society, which manages Brookfield Zoo, shows how related birds are able to recognize each other. The study, published Wednesday, Sept. 21 in the article, “Odor-based Recognition of Familiar and Related Conspecifics: A First Test Conducted on Captive Humboldt Penguins (Spheniscus humboldti)” in the journal PLoS ONE, could help conservationists design programs to help preserve endangered species.
“Smell is likely the primary mechanism for kin recognition to avoid inbreeding within the colony,” said Heather Coffin, lead author of the paper.
Coffin conducted the research while a graduate student at UChicago and was joined in writing the paper by Jill Mateo, associate professor in Comparative Human Development at UChicago, and Jason Watters, director of animal behavior research for the Chicago Zoological Society.
“This is the first study to provide evidence for odor-based kin discrimination in birds,” said Mateo, who is a specialist on kin recognition.
Experts said the work offers important insights into how birds use smell to guide behavior.
“The work by the research group is truly groundbreaking in that it shows for the first time ever in birds how the olfactory sense of captive penguins is both informative and functional in a behaviorally critical context: namely the recognition of friends from foes in general, and relatives from non-relatives in particular,” said Mark E. Hauber, professor of psychology at Hunter College, a specialist on bird social recognition.
Penguins are ideal subjects because they typically live in colonies made up of thousands of birds. They live in monogamous pairs — an arrangement that facilitates rearing of their young, since parents frequently take turns leaving the nest to gather food. Despite the size of the community, mates are able to find each other after traveling for days foraging for food in the ocean.
Research on other sea birds has shown that smell helps guide birds to their home territory and helps them forage for food. Other research has shown that birds could use sound and sight to recognize each other, but no other studies have shown that smell might be used in connection with kin recognition, Mateo said.
In the study conducted at Brookfield Zoo, researchers first sought to determine if the penguins were able to recognize familiar individuals by smell. They constructed an experiment using a dozen penguins, from a group that included breeding pairs, their offspring and nonbreeding individuals. The birds — all Humboldt penguins—endangered natives of Peru—were from groups either on exhibit or off exhibit.
The zoo is an ideal setting for the research, as it has extensive records on which penguins are related and have been housed together, Watters said.
Researchers took odor samples from glands near the penguins’ tails, where an oil that the birds use for preening is secreted. They put the oil on cotton swabs and rubbed the odor inside dog kennels, similar to the enclosures penguins at a zoo use for their nests. They also put the odor on paper coffee filters and placed them under mats inside the kennels.
When the penguins were released to the area containing the kennels, the researchers found that penguins spent more time in the kennels with familiar odors. The penguins were able to distinguish between the odors of birds they spent time with and the odors of unfamiliar penguins.
“What I found particularly notable about the study was that the authors identified the oil secreted from the penguins’ preen gland, which is rubbed on the feathers to make them water repellent, as the odor source used in recognition,” said Bryan D. Neff, professor and associate chairof biology, University of Western Ontario and an expert on kin recognition. “Oils are used in kin recognition by species of other animals, most notably a variety of insect species, including bees and wasps, which when considered with the penguin data provide a wonderful example of convergent evolution.”
“It’s important for birds that live in large groups in the wild, like penguins, to know who their neighbors are so that they can find their nesting areas and also, through experience, know how to get along with the birds nearby,” Watters said.
Because offspring usually return to the same colony for nesting, siblings have the potential of becoming mates, something that can be avoided by their smell mechanism, the new research shows.
Researchers also found that when the birds were exposed to the odors of unfamiliar kin and unfamiliar non-kin, they spent more time in the kennels with odors of unfamiliar non-kin, indicating they were probably able to determine by smell which animals they were related to and were more curious about the novel odors. Being able to make the distinction may help the penguins avoid mating with kin, researchers said. The discovery also could assist zoos in managing their breeding programs.
“It could also be true that birds do a better job determining who potential mates are than do people in zoos, who spend a great deal of time lining up the appropriate matches,” Watters said.
The ability of birds to be able to recognize familiar scents and thus be guided to their home territory also has potential value to naturalists, he said. “You could imagine that if you were trying to reintroduce birds to an area, you could first treat the area with an odor the birds were familiar with. That would make them more likely to stay.
source
The research by the University of Chicago and the Chicago Zoological Society, which manages Brookfield Zoo, shows how related birds are able to recognize each other. The study, published Wednesday, Sept. 21 in the article, “Odor-based Recognition of Familiar and Related Conspecifics: A First Test Conducted on Captive Humboldt Penguins (Spheniscus humboldti)” in the journal PLoS ONE, could help conservationists design programs to help preserve endangered species.
“Smell is likely the primary mechanism for kin recognition to avoid inbreeding within the colony,” said Heather Coffin, lead author of the paper.
Coffin conducted the research while a graduate student at UChicago and was joined in writing the paper by Jill Mateo, associate professor in Comparative Human Development at UChicago, and Jason Watters, director of animal behavior research for the Chicago Zoological Society.
“This is the first study to provide evidence for odor-based kin discrimination in birds,” said Mateo, who is a specialist on kin recognition.
Experts said the work offers important insights into how birds use smell to guide behavior.
“The work by the research group is truly groundbreaking in that it shows for the first time ever in birds how the olfactory sense of captive penguins is both informative and functional in a behaviorally critical context: namely the recognition of friends from foes in general, and relatives from non-relatives in particular,” said Mark E. Hauber, professor of psychology at Hunter College, a specialist on bird social recognition.
Penguins are ideal subjects because they typically live in colonies made up of thousands of birds. They live in monogamous pairs — an arrangement that facilitates rearing of their young, since parents frequently take turns leaving the nest to gather food. Despite the size of the community, mates are able to find each other after traveling for days foraging for food in the ocean.
Research on other sea birds has shown that smell helps guide birds to their home territory and helps them forage for food. Other research has shown that birds could use sound and sight to recognize each other, but no other studies have shown that smell might be used in connection with kin recognition, Mateo said.
In the study conducted at Brookfield Zoo, researchers first sought to determine if the penguins were able to recognize familiar individuals by smell. They constructed an experiment using a dozen penguins, from a group that included breeding pairs, their offspring and nonbreeding individuals. The birds — all Humboldt penguins—endangered natives of Peru—were from groups either on exhibit or off exhibit.
The zoo is an ideal setting for the research, as it has extensive records on which penguins are related and have been housed together, Watters said.
Researchers took odor samples from glands near the penguins’ tails, where an oil that the birds use for preening is secreted. They put the oil on cotton swabs and rubbed the odor inside dog kennels, similar to the enclosures penguins at a zoo use for their nests. They also put the odor on paper coffee filters and placed them under mats inside the kennels.
When the penguins were released to the area containing the kennels, the researchers found that penguins spent more time in the kennels with familiar odors. The penguins were able to distinguish between the odors of birds they spent time with and the odors of unfamiliar penguins.
“What I found particularly notable about the study was that the authors identified the oil secreted from the penguins’ preen gland, which is rubbed on the feathers to make them water repellent, as the odor source used in recognition,” said Bryan D. Neff, professor and associate chairof biology, University of Western Ontario and an expert on kin recognition. “Oils are used in kin recognition by species of other animals, most notably a variety of insect species, including bees and wasps, which when considered with the penguin data provide a wonderful example of convergent evolution.”
“It’s important for birds that live in large groups in the wild, like penguins, to know who their neighbors are so that they can find their nesting areas and also, through experience, know how to get along with the birds nearby,” Watters said.
Because offspring usually return to the same colony for nesting, siblings have the potential of becoming mates, something that can be avoided by their smell mechanism, the new research shows.
Researchers also found that when the birds were exposed to the odors of unfamiliar kin and unfamiliar non-kin, they spent more time in the kennels with odors of unfamiliar non-kin, indicating they were probably able to determine by smell which animals they were related to and were more curious about the novel odors. Being able to make the distinction may help the penguins avoid mating with kin, researchers said. The discovery also could assist zoos in managing their breeding programs.
“It could also be true that birds do a better job determining who potential mates are than do people in zoos, who spend a great deal of time lining up the appropriate matches,” Watters said.
The ability of birds to be able to recognize familiar scents and thus be guided to their home territory also has potential value to naturalists, he said. “You could imagine that if you were trying to reintroduce birds to an area, you could first treat the area with an odor the birds were familiar with. That would make them more likely to stay.
source
Wednesday, September 21, 2011
Primitive Birds Shared Dinosaurs' Fate
The bones are from the 17 species of Cretaceous birds which went
extinct around the time of the dinosaurs. The two on the far left are
foot bones and the rest are shoulder bones. (Credit: Courtesy Yale
University)
ScienceDaily (Sep. 21, 2011)
— A new study puts an end to the longstanding debate about how archaic
birds went extinct, suggesting they were virtually wiped out by the same
meteorite impact that put an end to dinosaurs 65 million years ago.
Now a team of paleontologists led by Yale researcher Nicholas Longrich has provided clear evidence that many primitive bird species survived right up until the time of the meteorite impact. They identified and dated a large collection of bird fossils representing a range of different species, many of which were alive within 300,000 years of the impact.
"This proves that these species went extinct very abruptly, in terms of geological time scales," said Longrich. The study appears the week of Sept. 19 in the journal Proceedings of the National Academy of Sciences.
The team examined a large collection of about two dozen bird fossils discovered in North America -- representing a wide range of the species that existed during the Cretaceous -- from the collections of Yale's Peabody Museum of Natural History, the American Museum of Natural History, the University of California Museum of Paleontology, and the Royal Saskatchewan Museum. Fossil birds from the Cretaceous are extremely rare, Longrich said, because bird bones are so light and fragile that they are easily damaged or swept away in streams.
"The birds that had been discovered hadn't really been studied in a rigorous way," Longrich said. "We took a much more detailed look at the relationships between these bones and these birds than anyone had done before."
Longrich believes a small fraction of the Cretaceous bird species survived the impact, giving rise to today's birds. The birds he examined showed much more diversity than had yet been seen in birds from the late Cretaceous, ranging in size from that of a starling up to a small goose. Some had long beaks full of teeth.
Yet modern birds are very different from those that existed during the late Cretaceous, Longrich said. For instance, today's birds have developed a much wider range of specialized features and behaviors, from penguins to hummingbirds to flamingoes, while the primitive birds would have occupied a narrower range of ecological niches.
"The basic bird design was in place, but all of the specialized features developed after the mass extinction, when birds sort of re-evolved with all the diversity they display today," Longrich said. "It's similar to what happened with mammals after the age of the dinosaurs."
Longrich adds that this study is not the first to suggest that archaic birds went extinct abruptly. "There's been growing evidence that these birds were wiped out at the same time as the dinosaurs," Longrich said. "But this new evidence effectively closes the book on the debate."
Other authors of the paper include Tim Tokaryk (Royal Saskatchewan Museum) and Daniel Field (Yale University).
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Yale University.
Journal Reference:
- N. R. Longrich, T. Tokaryk, D. J. Field. Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary. Proceedings of the National Academy of Sciences, 2011; 108 (37): 15253 DOI: 10.1073/pnas.1110395108
Yale University (2011, September 21). Primitive birds shared dinosaurs' fate. ScienceDaily. Retrieved September 21, 2011, from http://www.sciencedaily.com /releases/2011/09/110919151315.htm
Friday, September 16, 2011
Trapping time in amber
September 15, 2011
A feather from the late Cretaceous is trapped in amber. The resin turned to resilient amber preserving some 80-million-year-old protofeathers, possibly from non-avian dinosaurs, as well as plumage that is very similar to modern birds, including those that can swim under water.
U of A paleontology graduate student Ryan McKellar discovered a wide range of feathers trapped in amber in collections at the Royal Tyrrell Museum and in the private collection of the Leuck family in Medicine Hat.
“Most of the feather specimens were probably blown into contact with the sticky surface of the resin and encapsulated by subsequent resin flows,” said McKellar.
The 11 feather specimens used by the U of A team were all found near the community of Grassy Lake in southern Alberta. The research specimens are described as the richest amber feather find from the late Cretaceous period.
“The amber preserves microscopic detail of the feathers and even their pigment or colour,” said McKellar. “I would describe the colours as typically ranging from brown to black.”
During the late Cretaceous, southern Alberta was a warm coastal region. “The trees that produced the resin were probably comparable to the redwood forests of the Pacific Northwest,” said McKellar.
No dinosaur or avian fossils were found in direct association with the amber feather specimens, but McKellar says comparison between the amber and fossilized feathers found in rock strongly suggest that some of the Grassy Lake specimens are from dinosaurs. The non-avian dinosaur evidence points to small theropods as the source of the feathers.
McKellar says that some of the feather specimens can take on water, enabling the bird to dive more effectively and are very similar to those of modern birds like the Grebe, which are able to swim underwater.
“The preservation of microscopic detail and pigmentation has provided a unique snapshot of feathers and their uses in the late Cretaceous forests of Alberta,” said McKellar.
The U of A team’s research was published Sept. 15, in the journal Science.
source
Tuesday, September 13, 2011
How penguins find a perfect partner
King
penguin parents spend about 14 months incubating their egg, then
rearing their chick. They take it in turns to find food, so the strength
of their bond is crucial. Biologists want to know how they make this
important mate selection, and even how the birds tell a male from a
female; the two sexes look almost identical.
Prof Stephen Dobson from the National Centre for Scientific Research in
Montpellier, France, playfully sums up his research: "I'm trying to work
out what makes a sexy penguin." His studies of the birds on Kerguelen
Island have revealed that penguins often struggle to spot a member of
the opposite sex.
Prof Dobson also found that males on the island in the Southern Indian
Ocean often had to compete particularly hard to snag a female mate. He
and his team noticed that, during mating season, trios of penguins would
"parade" around together. DNA analysis showed that the trios were
usually two males pursuing a female.
When the penguins do find a mate that they take a shine to they carry
out an intimate dance – stretching their necks from side to side in what
appears to be an elaborate embrace. Occasionally, two males will engage
in this mating dance, but the pair usually separate when one finds a
female partner.
Prof Dobson’s team, which also includes researchers from the Centre for
Functional and Evolutionary Ecology in Montpellier, France, has found
that the penguins' bright yellow ear patches play an important role in
attraction.
The scientists hope to unpick the evolutionary mystery of how these birds select a suitable partner who will co-operate in the care of their egg and chick. They also hope to find out more about the penguins' natural behavior to see how they are being affected by environmental change.
Subscribe to:
Posts (Atom)
