Melting Sea Ice Threatens Emperor Penguins

At nearly four feet tall, the Emperor penguin is Antarctica’s largest sea bird. Unlike other sea birds, Emperor penguins breed and raise their young almost exclusively on sea ice. If global temperatures continue to rise, the Emperor penguins in Terre Adélie in East Antarctica may eventually disappear. (Credit: Photo courtesy Glen Grant, U.S. Antarctic Program, National Science Foundation)

 

ScienceDaily (June 20, 2012) — At nearly four feet tall, the Emperor penguin is Antarctica's largest sea bird -- and thanks to films like "March of the Penguins" and "Happy Feet," it's also one of the continent's most iconic. If global temperatures continue to rise, however, the Emperor penguins inTerre Adélie, in East Antarcticamay eventually disappear, according to a new study by led by researchers from the Woods Hole Oceanographic Institution (WHOI).

The study was published in the June 20th edition of the journal Global Change Biology.
"Over the last century, we have already observed the disappearance of the Dion Islets penguin colony, close to the West Antarctic Peninsula," says Stephanie Jenouvrier, WHOI biologist and lead author of the new study. "In 1948 and the 1970s, scientists recorded more than 150 breeding pairs there. By 1999, the population was down to just 20 pairs, and in 2009, it had vanished entirely." Like in Terre Adélie, Jenouvrier thinks the decline of those penguins might be connected to a simultaneous decline in Antarctic sea ice due to warming temperatures in the region.

Unlike other sea birds, Emperor penguins breed and raise their young almost exclusively on sea ice. If that ice breaks up and disappears early in the breeding season, massive breeding failure may occur, says Jenouvrier. "As it is, there's a huge mortality rate just at the breeding stages, because only 50 percent of chicks survive to the end of the breeding season, and then only half of those fledglings survive until the next year," she says.

Disappearing sea ice may also affect the penguins' food source. The birds feed primarily on fish, squid, and krill, a shrimplike animal, which in turn feeds on zooplankton and phytoplankton, tiny organisms that grow on the underside of the ice. If the ice goes, Jenouvrier says, so too will the plankton, causing a ripple effect through the food web that may starve the various species that penguins rely on as prey.

To project how penguin populations may fare in the future, Jenouvrier's team used data from several different sources, including climate models, sea ice forecasts, and a demographic model that Jenouvrier created of the Emperor penguin population at Terre Adélie, a coastal region of Antarctica where French scientists have conducted penguin observations for more than 50 years.

Combining this type of long-term population data with information on climate was key to the study, says Hal Caswell, a WHOI senior mathematical biologist and collaborator on the paper.

"If you want to study the effects of climate on a particular species, there are three pieces that you have to put together," he says. "The first is a description of the entire life cycle of the organism, and how individuals move through that life cycle. The second piece is how the cycle is affected by climate variables. And the crucial third piece is a prediction of what those variables may look like in the future, which involves collaboration with climate scientists."

Marika Holland of the National Center for Atmospheric Research is one such scientist. She specializes in studying the relationship between sea ice and global climate, and helped the team identify climate models for use in the study.

Working with Julienne Stroeve, another sea ice specialist from the National Snow and Ice Data Center, Holland ultimately recommended five distinct models. "We picked the models based on how well they calculated the sea ice cover for the 20th century," she says. "If a model predicted an outcome that matched what was actually observed, we felt it was likely that its projections of sea ice change in the future could be trusted."

Jenouvrier used the output from these various climate models to determine how changes in temperature and sea ice might affect the Emperor penguin population at Terre Adélie. She found that if greenhouse gas emissions continue to rise at levels similar to today -- causing temperatures to rise and Antarctic sea ice to shrink -- penguin population numbers will diminish slowly until about 2040, after which they would decline at a much steeper rate as sea ice coverage drops below a usable threshold.

"Our best projections show roughly 500 to 600 breeding pairs remaining by the year 2100. Today, the population size is around 3000 breeding pairs," says Jenouvrier.

The effect of rising temperature in the Antarctic isn't just a penguin problem, according to Caswell. As sea ice coverage continues to shrink, the resulting changes in the Antarctic marine environment will affect other species, and may affect humans as well.

"We rely on the functioning of those ecosystems. We eat fish that come from the Antarctic. We rely on nutrient cycles that involve species in the oceans all over the world," he says. "Understanding the effects of climate change on predators at the top of marine food chains -- like Emperor penguins -- is in our best interest, because it helps us understand ecosystems that provide important services to us."
Also collaborating on the study were Christophe Barbraud and Henri Weimerskirch of the Centre d'Etudes Biologiques de Chizé, in France, and Mark Serreze of the National Snow and Ice Data Center in the United States.

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Story Source:

The above story is reprinted from materials provided by Woods Hole Oceanographic Institution.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Stephanie Jenouvrier, Marika Holland, Julienne Stroeve, Christophe Barbraud, Henri Weimerskirch, Mark Serreze, Hal Caswell. Effects of climate change on an emperor penguin population: analysis of coupled demographic and climate models. Global Change Biology, 2012; DOI: 10.1111/j.1365-2486.2012.02744.x

Woods Hole Oceanographic Institution (2012, June 20). Melting sea ice threatens emperor penguins. ScienceDaily. Retrieved June 21, 2012, from http://www.sciencedaily.com­ /releases/2012/06/120620113342.htm ­ /

36% of Chinstrap Penguins Missing from Antarctic Island

Jeanna Bryner, LiveScience Managing Editor

Date: 19 June 2012


A population of chinstrap penguins is feeling the heat, with more than one-third of a breeding colony lost in the past 20 years, new research finds.

A warming planet, which is causing sea ice in Antarctica (and elsewhere) to melt, may ultimately be to blame for the plummeting penguin population, the researchers said. That's because the chinstraps' main food, shrimplike creatures called krill, depend on algae that attaches to that ice.

"Actually, in the '90s it was thought that the climate change would favor the chinstrap penguin, because this species prefers sea waters without ice, unlike the Adélie penguin, which prefers the ice pack," study researcher Andres Barbosa told LiveScience. He added that at the time, chinstraps, named for the thin black facial line from cheek to cheek, seemed to increase in numbers, with some new colonies being established.


The sea-ice decline in the winter, however, has become so big that it is now impacting krill populations, said Barbosa, of the National Museum of Natural Sciences in Madrid.

Counting chinstraps

Barbosa and his colleagues tallied chinstrap penguins (Pygoscelis antarctica) in the Vapour Col colony of Deception Island, in the Antarctic's South Shetland Islands in 1991-92 and 2008-09. They photographed nests in 19 subcolonies, mainly in December when chicks were hatching.


Results, which ended up including just 12 of the subcolonies due to availability of data, showed the occupied nests had declined by 36 percent between 1991 and 2008.

Barbosa and colleagues ruled out research activity as the cause for the loss since both studied populations and those used as controls showed similar patterns of decline.

Tourism is also not a likely culprit. Deception Island, built on a volcano, is one of the most visited places in Antarctica; the 2007-08 year saw some 25,000 visitors, according to the International Association of Antarctica Tour Operators (IAATO). Meanwhile, the nearby chinstrap penguin colony of Bailey Head, which is usually visited by 2,000 to 3,500 people every season, showed a decline of about 50 percent.

Rather, a dip in the krill population may be to blame, an idea supported by the fact that Adélie penguin population (P. adeliae) in the region is also declining, while the gentoo penguin population (P. papua), which has a more variable diet, is not.

(The chinstrap, gentoo and Adélie penguins are the three pygoscelid species (in the Pygoscelis genus) that inhabit the Antarctic Peninsula, the region of the Antarctic continent where the effects of climate change are more evident, the researchers noted.)

Saving penguins

But Barbosa says the chinstraps aren't a lost cause.

"This is an example of how the human activity far from the poles can affect the life at thousands of kilometers far from our homes," Barbosa told LiveScience. "Therefore, a more responsible use of the energy and the fossil fuels is necessary to preserve the planet and then the Antarctica."

In addition, he said, to protect the organisms that call the Antarctic home, we need to reduce human impact by reducing overfishing, tourism and even research activity.

The research was detailed online May 22 in the journal Polar Biology.

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Chin StrapCredit: Andres BarbosaNamed for the thin black band of feathers that extends from ear to ear under their heads, chinstrap penguins grow to about 2.2 feet (68 centimeters) tall, with males being larger and heavier than females.  

Two ChicksCredit: Andres BarbosaThe female usually lays two eggs in a shallow nest in late November, with each of the pair participating in incubation duties. The chicks hatch after about 33 to 35 days.  

Deception IslandCredit: Andres BarbosaAndres Barbosa of the National Museum of Natural Sciences in Madrid and his team have been studying the chinstrap penguins of Deception Island since 1999. Its volcanic origins have shaped the island into a horseshoe shape, with the volcano's caldera at the center. The island is one of the most visited of Antarctica, drawing some 25,000 visitors in the year 2007-08.  

Find the MateCredit: Andres BarbosaMonogamy between chinstrap penguin couples often persists from year to year, with pairs even using the same nesting sites in successive years. To make sure they've got the right mate, the penguins use certain mate-recognition behavior, seen here between a pair of chinstraps, which involves the penguins pumping their chests and stretching their heads upward. 

Little NestsCredit: Andres BarbosaFemale chinstrap penguins form a circular platform nest with a shallow interior. The nests are roughly about 16 inches (40 cm) across and up to 6 inches (15 cm) high.  

Chick HuddleCredit: Andres BarbosaTypically, fledgling occurs at about 7 to 8 weeks, with the chinstrap penguin chicks eventually forming crèches, or groups of young penguins that huddle together for warmth and protection. Then, at about 50-60 days old, once the chicks have molted, they head out to sea. 

Penguin TeamCredit: Andres BarbosaThe penguin team, including Barbosa, shown here with chinstrap penguins on Deception Island. 

Nest ChecksCredit: Andres BarbosaThe researchers tallied the occupied nests on the island in 1991-92 and 2008-09. Here they are checking chinstrap nests. (They also used photographic evidence for nest counts.) 

Main FoodCredit: Andres BarbosaThe culprit for the decline is likely a loss of their main prey, tiny shrimplike creatures called krill. The krill eat algae that attach to the sea ice, so without sea ice the krill plummet, followed by a decline in chinstrap penguins. 

Little BeaksCredit: Andres BarbosaResearchers measure the beak of a chinstrap penguin on Deception Island. 

Penguins PlummetCredit: Andres BarbosaThe researchers found occupied nests on the island have declined by about 36 percent between 1991 and 2008. 

Sea IceCredit: Andres BarbosaSea ice around the Antarctic's Deception Island. "Actually, in the 90's it was thought that the climate change would favor the chinstrap penguin, because this species prefers sea waters without ice unlike the Adelie penguin which prefers the ice pack," study researcher Andres Barbosa told LiveScience. The sea-ice decline in the winter, however, has become so big that it is now impacting krill populations, said Barbosa, of the National Museum of Natural Sciences in Madrid.  

Icy IncubationCredit: Andres BarbosaA chinstrap penguin nesting in the snow. 

Saving ChinstrapsCredit: Andres BarbosaBut Barbosa says the chinstraps aren't a lost cause. "This is an example of how the human activity far from the poles can affect the live at thousands of kilometers far from our homes," Barbosa told LiveScience. "Therefore, a more responsible use of the energy and the fossil fuels is necessary to preserve the planet and then the Antarctica." 

Penguin ProtectionCredit: Andres BarbosaIn addition, he said, to protect the organisms that call the Antarctic home we need to reduce human impact by reducing overfishing, tourism and even research activity. source 

Ancient Warming Greened Antarctica, Study Finds

This artist's rendition created from a photograph of Antarctica shows what Antarctica possibly looked like during the middle Miocene epoch, based on pollen fossil data. (Credit: NASA/JPL-Caltech/Dr. Philip Bart, LSU)

ScienceDaily (June 17, 2012) — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation -- including stunted trees -- along the edges of the frozen continent.

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The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana State University in Baton Rouge.

By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today.

"The ultimate goal of the study was to better understand what the future of climate change may look like," said Feakins, an assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. "Just as history has a lot to teach us about the future, so does past climate. This record shows us how much warmer and wetter it can get around the Antarctic ice sheet as the climate system heats up. This is some of the first evidence of just how much warmer it was."

Scientists began to suspect that high-latitude temperatures during the middle Miocene epoch were warmer than previously believed when co-author Sophie Warny, assistant professor at LSU, discovered large quantities of pollen and algae in sediment cores taken around Antarctica. Fossils of plant life in Antarctica are difficult to come by because the movement of the massive ice sheets covering the landmass grinds and scrapes away the evidence.

"Marine sediment cores are ideal to look for clues of past vegetation, as the fossils deposited are protected from ice sheet advances, but these are technically very difficult to acquire in the Antarctic and require international collaboration," said Warny.

Tipped off by the tiny pollen samples, Feakins opted to look at the remnants of leaf wax taken from sediment cores for clues. Leaf wax acts as a record of climate change by documenting the hydrogen isotope ratios of the water the plant took up while it was alive.

"Ice cores can only go back about one million years," Feakins said. "Sediment cores allow us to go into 'deep time.'"

Based upon a model originally developed to analyze hydrogen isotope ratios in atmospheric water vapor data from NASA's Aura spacecraft, co-author and JPL scientist Jung-Eun Lee created experiments to find out just how much warmer and wetter climate may have been.

"When the planet heats up, the biggest changes are seen toward the poles," Lee said. "The southward movement of rain bands associated with a warmer climate in the high-latitude southern hemisphere made the margins of Antarctica less like a polar desert, and more like present-day Iceland."

The peak of this Antarctic greening occurred during the middle Miocene period, between 16.4 and 15.7 million years ago. This was well after the age of the dinosaurs, which became extinct 64 million years ago. During the Miocene epoch, mostly modern-looking animals roamed Earth, such as three-toed horses, deer, camel and various species of apes. Modern humans did not appear until 200,000 years ago.

Warm conditions during the middle Miocene are thought to be associated with carbon dioxide levels of around 400 to 600 parts per million (ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the highest they've been in the past several million years. At the current rate of increase, atmospheric carbon dioxide levels are on track to reach middle Miocene levels by the end of this century.

High carbon dioxide levels during the middle Miocene epoch have been documented in other studies through multiple lines of evidence, including the number of microscopic pores on the surface of plant leaves and geochemical evidence from soils and marine organisms. While none of these 'proxies' is as reliable as the bubbles of gas trapped in ice cores, they are the best evidence available this far back in time. While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene, high carbon dioxide, together with the global warmth documented from many parts of the world and now also from the Antarctic region, appear to coincide during this period in Earth's history.

This research was funded by the U.S. National Science Foundation with additional support from NASA. The California Institute of Technology in Pasadena manages JPL for NASA.

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Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Sarah J. Feakins, Sophie Warny, Jung-Eun Lee. Hydrologic cycling over Antarctica during the middle Miocene warming. Nature Geoscience, 2012; DOI: 10.1038/ngeo1498

NASA/Jet Propulsion Laboratory (2012, June 17). Ancient warming greened Antarctica, study finds. ScienceDaily. Retrieved June 18, 2012, from  http://sciencedaily.com/releases/2012/06/120617170307.htm

Anthropomorphism is Dangerous in Science

9 June 2012 

'Depraved' sex acts by penguins shocked polar explorer

By Matt McGrath Science reporter, BBC World Service

 Scientists now understand the biological reasons for behaviour Dr Levick considered to be "depraved"

Accounts of unusual sexual activities among penguins, observed a century ago by a member of Captain Scott's polar team, are finally being made public.

Details, including "sexual coercion", recorded by Dr George Murray Levick were considered so shocking that they were removed from official accounts.
However, scientists now understand the biological reasons behind the acts that Dr Levick considered "depraved".

The Natural History Museum has published his unedited papers.
Dr Levick, an avid biologist, was the medical officer on Captain Scott's ill-fated Terra Nova expedition to the South Pole in 1910. He was a pioneer in the study of penguins and was the first person to stay for an entire breeding season with a colony on Cape Adare.
He recorded many details of the lives of adelie penguins, but some of their activities were just too much for the Edwardian sensibilities of the good doctor.

He was shocked by what he described as the "depraved" sexual acts of "hooligan" males who were mating with dead females. So distressed was he that he recorded the "perverted" activities in Greek in his notebook.

Graphic account

 

  On his return to Britain, Dr Levick attempted to publish a paper entitled "the natural history of the adelie penguin", but according to Douglas Russell, curator of eggs and nests at the Natural History Museum, it was too much for the times.
"He submitted this extraordinary and graphic account of sexual behaviour of the adelie penguins, which the academic world of the post-Edwardian era found a little too difficult to publish," Mr Russell said.

Pages from Dr Levick's notebook with some sections coded in Greek

 

The sexual behaviour section was not included in the official paper, but the then keeper of zoology at the museum, Sidney Harmer, decided that 100 copies of the graphic account should be circulated to a select group of scientists.
Mr Russell said they simply did not have the scientific knowledge at that time to explain Dr Levick's accounts of what he termed necrophilia.

"What is happening there is not in any way analogous to necrophilia in the human context," Mr Russell said. "It is the males seeing the positioning that is causing them to have a sexual reaction.
"They are not distinguishing between live females who are awaiting congress in the colony, and dead penguins from the previous year which just happen to be in the same position."
Sexual coercion

  Only two of the original 100 copies of Dr Levick's account survive. Mr Russell and colleagues have now published a re-interpretation of Dr Levick's findings in the journal Polar Record.
Mr Russell described how he had discovered one of the copies by accident.
"I just happened to be going through the file on George Murray Levick when I shifted some papers and found underneath them this extraordinary paper which was headed 'the sexual habits of the adelie penguin, not for publication' in large black type.

"It's just full of accounts of sexual coercion, sexual and physical abuse of chicks, non-procreative sex, and finishes with an account of what he considers homosexual behaviour, and it was fascinating."
The report and Dr Levick's handwritten notes are now on display at the Natural History Museum for the first time. Mr Russell believes they show a man who struggled to understand penguins as they really are.

"He's just completely shocked. He, to a certain extent, falls into the same trap as an awful lot of people in seeing penguins as bipedal birds and seeing them as little people. They're not. They are birds and should be interpreted as such."

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Gay, straight or necrophiliac, a penguin isn't a human being

By Tim Stanley Science
 June 9th, 2012

All ages of man have tried to understand penguin sexuality in human terms

An Edwardian notebook has gone on display at the Natural History Museum that describes the sexual activities of the Antarctic penguin. Read it and you’ll never look at Pingu the same way again.
The text was compiled by George Murray Levick, a scientist with the Scott Antarctic Expedition, and it contains details of homosexuality, pederasty, necrophilia and rape. In the Antarctic summer of 1911-1912, Levick observed the breeding cycle of the Adélies colony at Cape Adare. To his horror, he witnessed male penguins attempting to make love to the long-dead bodies of females, males getting it on with other males, and coercive sex acts with females and chicks that sometimes led to violence and death. It was Sodom in the snow.

It’s hardly news that penguins are motivated entirely by their loins, but what reports have seized upon is the charming way in which Levick processed this information. Being an Edwardian gentleman, he blamed the orgy on the male “hooligans,” perhaps believing that the lady penguins were incapable of bad behaviour. Describing what he saw as “astonishing depravity,” he recorded it all in Greek code and his findings were suppressed for many years. Reading Levick’s work, it’s hard not to spot traces of Judeo-Christian morality that seem inappropriate in the context of zoological study. Anything that an animal does cannot be depraved because they don’t have morals, or a rational soul.

But the temptation towards Anthropomorphism (the identifying of human characteristics among animals) didn’t stop in the Edwardian era. We still do it today – rationalising animal sexual behaviour in a different, yet still heavily politicised, way.

Take the case of the gay penguins. Inca and Rayas met at the Faunia Park in Madrid and seemed so devoted to each other that the zookeepers gave them their own egg. The pair have been dubbed “gay” and elevated to the status of the Elton and David of the animal kingdom. They are proof, for those seeking it, that gay monogamy finds a template in nature.

The problem is that the term “gay” is as inappropriate to describe what’s going on here as is Levick’s use of “depravity.” Gay is a term that has only been in use since the rights revolution of the 1960s and which describes far more than just homosexual activity; it denotes a politicised identity that makes no sense unless it is self-aware and publicly understood. Levick’s penguins face no moral choices, so they cannot be depraved. Inca and Rayas cannot conceptualise sexual category or identity, so they can’t be gay in the sense that a human being is. They certainly can't go through the rite of passage associated with being gay, "coming out." The thought of them waddling up to their parents – flipper in flipper – and telling them to prepare themselves for a shock is absurd.

Indeed, their zookeeper insists that they are not even homosexual – just “the best of friends.” There’s every expectation that they will, eventually, mate with a female. That’s happened in Tornoto, where the star “gay” couple, Buddy and Pedro, was paired off with females. The “bromance” was over when Buddy made it with a girl called Farai. Pedro chased the luscious Thandiwey for several weeks, but got nowhere. Buddy and Pedro’s relationship was never sexual, but instead social. That didn’t stop people asking if it was “homophobic” to separate them, as if some fundamental human right was being broken.

And what is happening here is the projection of human values onto a different species. At the same time that we more ruthlessly exploit animals than ever before, we also seem determined to find qualities within them that we can empathise with. We want to turn them into mirrors of ourselves. Sometimes – as with the Dachshund UN – the result is unbelievably cute. But in most instances it misleads about the nature of animals and blurs the lines between man and nature. Humanity shouldn’t judge its moral code by the sexual standards of the penguins. It should be guided by the uniquely human qualities of reason and compassion.

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Change in developmental timing was crucial in the evolutionary shift from dinosaurs to birds: study

Tyrannosaurus rex. Image: Nobu Tamura, via Wikipedia.

May 27 2012

 

At first glance, it's hard to see how a common house sparrow and a Tyrannosaurus Rex might have anything in common. After all, one is a bird that weighs less than an ounce, and the other is a dinosaur that was the size of a school bus and tipped the scales at more than eight tons.

 

For all their differences, though, scientists now say that two are more closely related than many believed. A new study, led by Harvard scientists, has shown that modern birds are, essentially, living dinosaurs, with skulls that are remarkably similar to those of their juvenile ancestors.

As reported in a May 27 paper in Nature, Arkhat Abzhanov, Associate Professor of Organismic and Evolutionary Biology and Bhart-Anjan Bhullar, a PhD student in Abzhanov laboratory and the first author of the study, found evidence that the evolution of birds is the result of a drastic change in how dinosaurs developed. Rather than take years to reach sexual maturity, as many dinosaurs did, birds sped up the clock – some species take as little as 12 weeks to mature – allowing them to retain the physical characteristics of baby dinosaurs.

"What is interesting about this research is the way it illustrates evolution as a developmental phenomenon," Abzhanov said. "By changing the developmental biology in early species, nature has produced the modern bird – an entirely new creature – and one that, with approximately 10,000 species, is today the most successful group of land vertebrates on the planet."

"The evolution of the many characteristics of birds – things like feathers, flight, and wishbones – has traditionally been a difficult problem for biologists," Mark Norell, chair of the Division of Paleontology at the American Museum of Natural History and one of the paper's co-authors, said. "By analyzing fossil evidence from skeletons, eggs, and soft tissue of bird-like dinosaurs and primitive birds, we've learned that birds are living theropod dinosaurs, a group of carnivorous animals that include Velociraptor. This new work advances our knowledge by providing a powerful example of how developmental changes played a major role in the origin and evolution of birds."


While it's clear simply from looking at the skulls of dinosaurs and modern birds that the two creatures are vastly different – dinosaurs have distinctively long snouts and mouths bristling with teeth, while birds have proportionally larger eyes and brains – it was the realization that skulls of modern birds and juvenile dinosaurs show a surprising degree of similarity that sparked the study.
"No one had told the big story of the evolution of the bird head before," Bhullar said. "There had been a number of smaller studies that focused on particular points of the anatomy, but no one had looked at the entire picture. What's interesting is that when you do that, you see the origins of the features that make the bird head special lie deep in the history of the evolution of Archosaurs, a group of animals that were the dominant, meat-eating animals for millions of years."

To tackle the problem, the researchers turned to an unusual methodology. Using CT scanners, they scanned dozens of skulls, ranging from modern birds to theropods – the dinosaurs most closely related to birds – to early dinosaur species. By marking various "landmarks" – such as the orbits, cranial cavity and other bones in the skull – on each scan, researchers were able to track how the skull changed shape over millions of years.

"We examined skulls from the entire lineage that gave rise to modern birds," Abzhanov said. "We looked back approximately 250 million years, to the Archosaurs, the group which gave rise to crocodiles and alligators as well as modern birds. Our goal was to look at these skulls to see how they changed, and try to understand what actually happened during the evolution of the bird skull."
What Abzhanov and colleagues found was surprising – while early dinosaurs, even those closely related to modern birds, undergo vast morphological changes as they mature, the skulls of juvenile and adult birds remain remarkably similar.

"This phenomenon, where a change in the developmental timing of a creature produces morphological changes is called heterochrony, and paedomorphosis is one example of it," Abzhanov explained. "In the case of birds, we can see that the adults of a species look increasingly like the juveniles of their ancestors."

In the case of modern birds, he said, the change is the result of a process known as progenesis, which causes an animal to reach sexual maturity earlier. Unlike their dinosaurian ancestors, modern birds take dramatically less time – just 12 weeks in some species – to reach maturity, allowing birds to retain the characteristics of their juvenile ancestors into adulthood.

"This study is a prime example of the heuristic power in multidisciplinary, specimen-based, anatomical research," said Gabe Bever of NYIT's New York College of Osteopathic Medicine and a co-author of the paper. "That the mechanisms of evolutionary events millions of years old can be circumscribed with this combination of modern and fossil specimens is remarkable."

Ultimately, Abzhanov said, the way the bird skull evolved – through changes in the developmental timeline – highlights the diversity of evolutionary strategies that have been used over millions of years.
"That you can have such dramatic success simply by changing the relative timing of events in a creature's development is remarkable," he said. "We now understand the relationship between birds and dinosaurs that much better, and we can say that, when we look at birds, we are actually looking at juvenile dinosaurs."

"It shows that there's so much for evolution to act upon," Bhullar agreed. "When we think of an organism, especially a complex organism, we often think of it as a static entity, but to really study something you have to look at its whole existence, and understand that one portion of its life can be parceled out and made into the entire lifespan of a new, and in this case, radically successful organism."

Journal reference: Nature

Provided by Harvard University  

Source 

Recommendations for Reading

Click here for a fascinating article on penguin eggs

I recommend NZ's Fossil Penguin Site-click this line

Read about Palaeeudyptes antarcticus here

Read more about Kairuku - the new "giant" Late Oligocene Penguin from New Zealand

The Rockhopper Penguin

Eudyptes chrysocome
rockhopper penguin

By Devon Phelan

• Classification

Kingdom Animalia (animals)
Eumetazoa (metazoans)
Bilateria (bilaterally symmetrical animals)
Deuterostomia (deuterostomes)
Phylum Chordata (chordates)
Craniata (craniates)
Subphylum Vertebrata (vertebrates)
Superclass Gnathostomata (jawed vertebrates)
Euteleostomi (bony vertebrates)
Class Sarcopterygii (lobe-finned fishes and terrestrial vertebrates)
Tetrapoda (tetrapods)
Amniota (amniotes)
Class Reptilia
Class Aves (birds)
Subclass Neognathae (neognath birds)
Infraclass Neoaves (modern birds)
Order Sphenisciformes (penguins)
Family Spheniscidae (penguins)
Genus Eudyptes (rockhopper, macaroni, and related penguins)
Species Eudyptes chrysocome (rockhopper penguin)
Subspecies Eudyptes chrysocome chrysocome
Subspecies Eudyptes chrysocome filholi
Subspecies Eudyptes chrysocome moseleyi

Geographic Range

Rockhopper penguins are found on islands in the southern ocean, such as the Falkland Islands. They occur farther north than many other penguin species.

Biogeographic Regions
neotropical (Native ); atlantic ocean (Native )

Habitat

Rockhopper penguins are found in high grasses called tussocks, where they make burrows and nest. As their name implies, they live on rocky shorelines.

Habitat Regions
temperate ; terrestrial ; saltwater or marine

Terrestrial Biomes
savanna or grassland

Aquatic Biomes
coastal

Physical Description

Range mass
2000 to 3000 g
(70.48 to 105.73 oz)

Average length
55 cm
(21.65 in)

Rockhopper penguins measure about 55 centimeters in length and weigh around 2.5 kilograms. These birds stand upright on two short feet. Their legs are set far back on the body. The waterproof coat, composed of feathers that average 2.9 centimeters in length, is white on the underside and bluish-black on the top. The head has bright yellow plumage on the brow; the yellow feathers extend along the sides. The top of the head has spiked black feathers. The wings are strong, stiff, narrow and flipper-like. Rockhopper penguins have tiny eyes.

Other Physical Features
endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism
sexes alike

Reproduction

Mating calls, which are species specific, are called "ecstatic vocalization." This draws attention to the bird and announces its intentions. Penguins mate with the same partners from previous years. (Williams, 1981)

Mating System
monogamous

 

Breeding interval
Rockhopper penguins breed once yearly.

Range eggs per season
1 to 2

Rockhopper penguins typically mate in the early spring or late summer, enabling the young to go to the sea in the mid-summer. They mate in vast colonies and lay up to two eggs, although sometimes pairs "adopt" a third egg. The first egg is usually 20-50% smaller than second one. The small egg is usually lost, although it is capable of maturing into a normal bird. Adopted eggs are also typically lost. After each egg is laid, it is turned over to the male who sits on it and keeps it in his brood pouch for the next four months until it hatches. (Williams, 1981)

Key Reproductive Features
seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

While the male penguin sits on the incubating egg, he is nourished by the female, or else he fasts for the entire period. If the female does not return with food for the chick once it has hatched, the male produces "penguin's milk" from his digestive system and regurgitates it for the baby.

Parental Investment
precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male)

Lifespan/Longevity

Average lifespan
Status: wild
10 years

The average lifespan of a rockhopper penguin is 10 years.

Behavior

Penguins are very sociable animals. It is very rare to see one alone. Rockhopper penguins are the most aggressive, as well as the most numerous, penguins. They hide their heads under their wing while they rest. Rockhopper penguins leave the breeding colony in late summer or fall and spend 3-5 months at sea, where they find food. Penguin wings are used exclusively for swimming, these sea birds do not fly.

Key Behaviors
natatorial ; diurnal ; territorial ; social ; colonial 

Communication and Perception

Their loud cry, "ecstatic vocalization", is used to announce their presence, attract a mate, or announce the boundaries of their territory. As well as vocalizing, these birds shake their heads and cause their yellow eyebrows to fly into a "halo" in order to attract a mate.

Communication Channels
visual ; acoustic

Food Habits

Rockhopper penguins eat primarily krill (Euphausiacea). They also eat squid and other crustaceans. They make daily trips to the sea to forage.

Primary Diet
carnivore (Eats non-insect arthropods)
Animal Foods
fish; aquatic crustaceans

Economic Importance for Humans: Positive

Penguins are a tourist attraction, and they are one of the main reasons people travel to the Falkland Islands and other habitats of these penguins.

Conservation Status

IUCN Red List of Threatened Species [Link]
Vulnerable

More Information

CITES [Link]

No special status

It is estimated that rockhopper penguins have undergone a decline of more than 30% in their total population size over the past 30 years. For this reason, they are classified as vulnerable by the IUCN. If the decline continues, they may be uplisted to endangered in the near future. Threats to rockhopper penguin populations include commercial fishing, which reduces the amount of available prey, and oil spills. (Bingham, 2002; BirdLife International, 2004; Ryan and Cooper, 1991)

Other Comments

Rockhopper penguins keep warm by their well-developed fat layer and system for maintaining heat.

Contributors

Tanya Dewey (editor), Animal Diversity Web, University of Michigan Museum of Zoology.
Devon Phelan (author), University of Michigan.

References

Gorman, James. 1990. The Total Penguin. Prentice Hall Press, NY.

Grzimek, Dr.Dr.h.c. Bernhard. 1972. Grzimek's Animal Life Encyclopedia. p.133-134. Van Norstrand Reinhold Co. NY.

New Scientist. "Did Warm Water Kill Falkland Penguins?" IPC Magazine Ltd. Vol. 114. May 28, 1987. p.22.

Bingham, M. 2002. The decline of Falkland Islands penguins in the presence of a commercial fishing industry. Revista Chilena de Historia Natural, 75(4): 805-818.

BirdLife International, 2004. "Eudyptes chrysocome" (On-line). 2004 IUCN Red List of Threatened Species. Accessed November 14, 2005 at www.redlist.org.

Ryan, P., J. Cooper. 1991. Rockhopper penguins and other marine life threatened by drift net fisheries at Tristan da Cunha, South Atlantic Ocean. Oryx, 25(2): 76-79.

Williams, A. 1981. The clutch size of macaroni penguins Eudyptes chrysolophus and rockhopper penguins Eudyptes chrysocome. Emu, 81(2): 87. 

 

To cite this page: Phelan, D. 1999. "Eudyptes chrysocome" (On-line), Animal Diversity Web. Accessed May 16, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Eudyptes_chrysocome.html

 

 Left: Grey morph of the Eastern Screech Owl (Megascops asio). Right: Rufous morph of the Eastern Screech Owl. (Credit: Left: Wolfgang Wander via Wikipedia, Creative Commons license; Right: Greg Hume via Wikipedia, Creative Commons license)

Bird Color Variations Speed Up Evolution

ScienceDaily (May 9, 2012) — Researchers have found that bird species with multiple plumage colour forms within in the same population, evolve into new species faster than those with only one colour form, confirming a 60-year-old evolution theory.

The global study used information from birdwatchers and geneticists accumulated over decades and was conducted by University of Melbourne scientists Dr Devi Stuart-Fox and Dr Andrew Hugall (now based at the Melbourne Museum) and is published in the journal Nature.

The link between having more than one colour variation (colour polymorphism) like the iconic red, black or yellow headed Gouldian finches, and the faster evolution of new species was predicted in the 1950s by famous scientists such as Julian Huxley, but this is the first study to confirm the theory.
By confirming a major theory in evolutionary biology, we are able to understand a lot more about the processes that create biodiversity said Dr Devi Stuart-Fox from the University's Zoology Department.

"We found that in three families of birds of prey, the hawks and eagles, the owls and the nightjars, the presence of multiple colour forms leads to rapid generation of new species," Dr Stuart-Fox said.
"Well known examples of colour polymorphic species in these families include the Australian grey goshawk which has a grey and pure white form, the North American eastern screech owl and the Antillean nighthawk, each with grey and red forms."

The team focused on birds because although colour polymorphism occurs in many animals (such as fish, lizards, butterflies and snails), there is a wealth of information on colour variation in birds, as well as on species classification (taxonomy), partly thanks to birdwatchers or 'twitchers'.
"We looked at five bird families with a high proportion of colour polymorphism and compared their rates of evolution with those with only one colour form," Dr Stuart-Fox said.

By modeling evolutionary rates using publicly available genetic information accumulated over a quarter of a century, the study found that colour polymorphism speeds up the generation of new species. Colour polymorphic species tend to evolve into species with only one colour form (monomorphic), explaining why existing species with different colour forms are relatively young and also rare.

The study found that colour polymorphic species were younger not only in the birds of prey but in the songbirds, which account for more than half of the world's bird species.

Study co-author Dr Andrew Hugall noted that when scientists like Julian Huxley proposed that colour polymorphism speeds up the generation of new species over half a century ago, they did not have the huge amounts of data needed to support it.

"Using many decades of natural history information and 25 years of genetic sequence information we were able to generate the massive family trees, such as a tree of more than four thousand songbirds, needed to model rates of bird evolution in this study," he said.

"Now that we've identified this pattern for the first time, our next step is to test some of the explanations proposed for why colour polymorphism leads to accelerated evolution."

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Story Source:

The above story is reprinted from materials provided by University of Melbourne.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Andrew F. Hugall, Devi Stuart-Fox. Accelerated speciation in colour-polymorphic birds. Nature, 2012; DOI: 10.1038/nature11050

University of Melbourne (2012, May 9). Bird color variations speed up evolution. ScienceDaily. Retrieved May 11, 2012, from ­source

 

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 **My Note: So does this mean that this explains the lack of speciation in penguins over the millenia?**

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World Penguin Day