Friday, October 31, 2008

Thursday, October 30, 2008

Dino's Sense of Smell Opens New Discussion on Bird Evolution




Science News

Dinosaur Smelling Skills Open New Angle On Bird Evolution


ScienceDaily (Oct. 29, 2008) — Although we know quite a bit about the lifestyle of dinosaur; where they lived, what they ate, how they walked, not much was known about their sense of smell, until now.

Scientists at the University of Calgary and the Royal Tyrrell Museum are providing new insight into the sense of smell of carnivorous dinosaurs and primitive birds in a research paper published in the British journal Proceedings of the Royal Society B.

The study, by U of C paleontologist Darla Zelenitsky and Royal Tyrrell Museum curator of dinosaur palaeoecology François Therrien, is the first time that the sense of smell has been evaluated in prehistoric meat-eating dinosaurs. They found that Tyrannosaurus rex had the best nose of all meat-eating dinosaurs, and their results tone down the reputation of T. rex as a scavenger.

The researchers looked at the importance of the sense of smell among various meat-eating dinosaurs, also called theropods, based on the size of their olfactory bulbs, the part of the brain associated with the sense of smell. Although the brains of dinosaurs are not preserved, the impressions they left on skull bones or the space they occupied in the skull reveals the size and shape of the different parts of the brain. Zelenitsky and Therrien CT-scanned and measured the skulls of a wide variety of theropod dinosaurs, including raptors and ostrich-like dinosaurs, as well as the primitive bird Archaeopteryx.

"T. rex has previously been accused of being a scavenger due to its keen sniffer, although its nose may point to alternative lifestyles based on what we see in living animals" says Zelenitsky, the lead investigator on the study. "Large olfactory bulbs are found in living birds and mammals that rely heavily on smell to find meat, in animals that are active at night, and in those animals that patrol large areas. Although the king of carnivorous dinosaurs wouldn't have passed on scavenging a free dead meal, it may have used its sense of smell to strike at night or to navigate through large territories to find its next victim."

In addition to providing clues about the biology and behavior of the ancient predators, the study also reveals some surprising information about the sense of smell in the ancestors of modern birds.

Therrien and Zelenitsky found that the extinct bird Archaeopteryx, known to have evolved from small meat-eating dinosaurs, had an olfactory bulb size comparable to most theropod dinosaurs. Although sight is very good in most birds today, their sense of smell is usually poor, a pattern that does not hold true in the ancestry of living birds.

"Our results tell us that the sense of smell in early birds was not inferior to that of meat-eating dinosaurs," says Therrien. "Although it had been previously suggested that smell had become less important than eye sight in the ancestors of birds, we have shown that this wasn't so. The primitive bird Archaeopteryx had a sense of smell comparable to meat-eating dinosaurs, while at the same time it had very good eye sight. The sense of smell must have become less important at some point during the evolution of those birds more advanced than Archaeopteryx."

Adapted from materials provided by University of Calgary.
Need to cite this story in your essay, paper, or report?

MLA
University of Calgary. "Dinosaur Smelling Skills Open New Angle On Bird Evolution." ScienceDaily 29 October 2008. 30 October 2008 .

Image of the Day



Seven primitive-looking feathers found in amber date back a hundred million years and could fill a key gap in the puzzle of how dinosaurs gave rise to birds, a new study says.

The feathers share features of feather-like fibers from two-legged dinosaurs known as theropods and of modern bird feathers, researchers say.

Photograph courtesy Didier Néraudeau and National Geographic @

http://news.nationalgeographic.com/news/bigphotos/56427251.html

Wednesday, October 29, 2008

Image of the Day



Late Cretaceous map

Excellent work from Dr. Ron Blakely @
http://jan.ucc.nau.edu/~rcb7/RCB.html

I highly recommend his site for the best ever paleo maps.

Tuesday, October 28, 2008

Sunday, October 26, 2008

Image of the Day



Natural History painting courtesy of:
http://amykane.typepad.com/photos/uncategorized/2007/07/17/bluepenguin_2.jpg

Saturday, October 25, 2008

Some Dinos Breathed Like Penguins


Dinosaurs Like Velociraptor Breathed Like Penguins

10 September 2008

Dinosaurs like Velociraptors owe their fearsome reputation to the way they breathed, according to a UK study.

They had one of the most efficient respiratory systems of all animals, similar to that of modern diving birds like penguins, fossil evidence shows.

It fuelled their bodies with oxygen for the task of sprinting after prey, say researchers at Manchester University.

The bipedal meat-eaters, the therapods, had air sacs ventilated by tiny bones that moved the ribcage up and down.

“Finding these structures in modern birds and their extinct dinosaur ancestors suggests that these running dinosaurs had an efficient respiratory system and supports the theory that they were highly active animals that could run relatively quickly when pursuing their prey,” said Dr Jonathan Codd, who led the research.

“It provides a mechanism for facilitating avian-like breathing in non-avian dinosaurs and it was there long before the evolution of flight occurred,” he told BBC News.

Bony projections

Modern-day birds have a highly specialised respiratory system, made up of a small rigid lung and around nine air sacs.

The bellows-like movement of the sternum and ribs moves air through the system.

Bony projections on the ribcage known as uncinate processes play an important role in both respiration and locomotion.

The small bones act as levers to move the ribs and sternum during breathing. They have become adapted in different types of birds to deal with different ways of getting around.

The bones are shortest in runners like emus that don’t need large breast muscles for flight, intermediate in flying birds and longest in divers such as the penguin.

The Manchester team studied a wealth of fossil remains of dinosaurs and extinct birds such as Archaeopteryx, and compared these with skeletons of living birds.

They found that uncinate processes are also found both in the extinct ancestors of birds, the theropod dinosaurs, and in modern species.

Dinosaurs are most like diving birds in their morphology.

“The dinosaurs we studied from the fossil record had long uncinate processes similar in structure to those of diving birds,” said Dr Codd.

“This suggests both dinosaurs and diving birds need longer lever arms to help them breathe,” he added.

The data, published in the Proceedings of the Royal Society B: Biological Sciences, may provide clues to how dinosaurs evolved and how they might have lived.

Article courtesy of BBC News: Helen Briggs

Image of the Day



Comparison of neurocranium of Archaeospheniscus wimani or Palaeeudyptes gunnari (specimen IB/P/B-0346) with a modern skull (Pygoscelis papua); dorsal view (see also Jadwiszczak 2006a).

Image courtesy of University of Bialystok @
http://biol-chem.uwb.edu.pl/IP/ENG/biologia/bones.htm

Thursday, October 23, 2008

Image of the Day--Epidexipteryx



The original paper that describes the newly discovered fossilized remains of Epidexipteryx is HERE

New Feathered Dino Discovered in China

Thank you, Krissa, for providing us with this news...





BBC NEWS
New feathered dinosaur discovered
By James Morgan
Science reporter, BBC News

The fossil of a "bizarre" feathered dinosaur from the era before birds evolved has been discovered in China.

Epidexipteryx was very bird-like, with four long ribbon-like tail feathers - probably used in display.

But the pigeon-sized creature shows no sign of the flight feathers seen in other bird-like dinosaurs, according to a report in the journal Nature.

The discovery highlights the diversity of species present in the Middle to Late Jurassic, just before birds arose.

The fossil was described by a team of palaeontologists led by Fucheng Zhang and Xing Xu, of the Chinese Academy of Sciences.

Dr Angela Milner, Associate Keeper of Palaeontology at the Natural History Museum, London, said: "This exquisitely preserved fossil is an exciting and totally unexpected find.

"It shows that feathers were likely being used for ornamentation for many millions of years before they were modified for flight.

"It provides fascinating evidence of evolutionary experiments with feathers that were going on before small dinosaurs finally took to the air and became birds."

Air of mystery

The discovery adds yet more complexity to the early history of the era when small meat-eating bipedal dinosaurs evolved into birds.

Many feathered dinosaurs have been unearthed at the now famous fossil site in Laioning Province in China. These include the oldest known bird, Archaeopteryx , which lived around 125 million years ago.

Epidexipteryx was a primitive, flightless member of the avialae clade, which lived a little before Archaeopteryx.

It was discovered at the Daohugou beds, in Nincheng County, Inner Mongolia, in sediments which have been radiocarbon dated to around 168-152 million years ago.

Phylogenetic analysis indicates the species is a member of a "bizarre lineage" of the avialae clade, known as the scansoriopterygidae (meaning "climbing wings").

The authors note that it displays "an unexpected combination of characters" seen in several different groups of theropods - the bipedal dinosaurs which eventually gave rise to birds.

Freak experiment

It had a fluffy, down-like covering and sprouted two pairs of enormously long, ribbon-like shafted tail feathers. These were almost certainly used for display - making it the oldest known species to possess these.

But its limbs lacked contour feathers - a feature common to most modern birds.

Dr Zhang said: "Although possessing many derived features seen in birds... [ Epidexipteryx ] show some striking features... not known in any other theropod.

"The bizarre appearance... indicates that morphological disparity... close to the origin of birds is higher than previously assumed.

"The absence of... limb feathers suggests that display feathers appeared before aerofoil feathers and flight ability.

"It underscores the importance of Jurassic theropods for understanding avian origins."

Dr Graham Taylor, of Oxford University's Animal Flight Group, said: "This fossil is the latest in a string of feathered dinosaurs emerging from China, but is especially exciting for two reasons.

"Firstly, whereas other feathered dinosaurs date from after the appearance of the first known bird, this fossil appears to be much closer in age, so it opens a new window on the evolutionary events at the critical transition from dinosaurs to birds.

"Secondly, it has an exquisite set of ornamental tail feathers, suggesting that feathers were used in show even before they were used in flight."

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/7684796.stm

Wednesday, October 22, 2008

Sunday, October 19, 2008

Image of the Day--Created by Spore and Myself




There is a great, low-cost program online that is more fun than any video game. Spore Creations by Electronic Arts allows one to create new beasties or just to recreate current or extinct ones. Of course, I had to make a penguin, but there's more to the program than mere aesthetics. The creator is compelled to think about what goes into the construction of said beasties. For example, the creator must determine how many vertebrae an animal should have or where to put the mouth (depending on how the creature feeds) or spacing of the eyes (is the creature given forward eyes or eyes on each side of the head--then to think why are those eyes placed just so).

The next step is to play around with evolution--what will the creature look like in, say, the next 10K years. The trick is to either improve or remove qualities already present within the creature. I can see this little program having much potential in provoking students to think beyond the game and into reality.

And so, here I present my own little Emperor Penguin. Enjoy!

(Link to Spore's website)
http://www.spore.com/ftl

Saturday, October 18, 2008

Friday, October 17, 2008

Image of the Day



Head and neck of Sinosauropteryx showing dense pelt (black) of fine, filament-like protofeathers (dino-fuzz). (Photo courtesy of Ji Qiang and Ji Shuan, Geol. Inst. Beijing)


http://www.charnia.org.uk/images_abstracts/sinosauropteryx_ss2008.jpg

Thursday, October 16, 2008

Wednesday, October 15, 2008

Tuesday, October 14, 2008

Adelie DNA --Climate Coping Within the Species



Antarctic DNA gives climate coping clues

Tuesday, 14 October 2008 Anna Salleh
ABC Science Online


Researchers say Adélie penguins have been surviving extreme climate change in Antarctica for hundreds and thousands of years (Source: Griffith University)
Related Stories

* Global warming may wipe out most birds
* Tropics the hot spot for speedy evolution
* A faster evolutionary clock?

DNA in the bones of Adélie penguins that survived the last ice age are helping to shed light on how other animals will cope with climate change, say researchers.

Evolutionary biologist Professor David Lambert of Griffith University in Brisbane and colleagues report their analysis of Adélie penguin DNA dating back to 37,000 years in the journal PLOS Genetics.

"Adélie penguins are a wonderful model to study the problem of climate change," says Lambert. "They have lived through temperature fluctuations much higher than those in equatorial regions."

Lambert says Adélie penguins have survived 10°C of warming since the last glacial maximum 18,000 years ago.

And he expects them to have been around 120,000 years earlier than that, during the peak of the ice age before last.

Adélie penguins are one of very few species that have survived in large numbers over such a long time, says Lambert.
Surviving climate change

Lambert says if species are able to move geographically there is evidence that they can combat climate change by staying within their preferred temperature range.

"The problem for Adélie penguins is they've got nowhere to go," says Lambert. "They're in the coldest place they can be."

He says the fact Adélie penguins have survived extreme changes in temperature may mean that some species are able to respond to climate change even when they can't move geographically.

Lambert and colleagues' research on the rate of evolution of Adélie penguins in Antarctica may help shed some light on why this is the case.
DNA analysis

The team analysed the number of mutations in the mitochondrial DNA of mothers and their chicks and compared this with DNA from ancestral penguins, taken from 37,000-year-old bones preserved in the extreme cold and dry conditions of Antarctica.

They found the rate of mutations between generations was the same as the rate over 37,000 years.

This is contrary to recent suggestions that evolution is faster over short time frames but slows down over long time frames, when the loss of genetic diversity due to speciation is taken into account.

Importantly, the rate of evolution of Adélie penguins found by Lambert and the team confirm earlier findings that the penguins evolve faster than previously thought, which may be one explanation for their ability to survive extreme variations in climate.

Other animals which have similarly high rates of evolution, are the tuatoara (a New Zealand reptile), bison, the brown bear and the cave lion, says Lambert.
Natural selection

Lambert says the DNA analysis has so far focused on genes not subject to natural selection.

He says these so-called "neutral" genes are important in developing an evenly ticking "molecular clock" for evolution.

Sequences under control of natural selection would change rapidly during some periods of time and hardly change at all at other periods of time.

Lambert says natural selection may also have played a role in Adélie penguin's survival in Antarctica and he hopes to also look at the mutation in genes that are subject to natural selection.
Raises questions

Evolutionary biologist Dr Jeremy Austin of the University of Adelaide says the work raises questions about the idea that evolution rates are time dependent.

But, he says it is possible that 37,000 years is not long enough for the slower evolutionary rate to show up.

"When we talk about evolutionary rates we're talking about things that are possibly a million years or more," Austin says.

He says sequencing even older DNA would be helpful as would comparing Adélie penguins with a sister species.

Lambert says he is confident the team will be able to obtain viable DNA from penguin remains preserved for hundreds of thousands of years many metres beneath the permafrost.

Story courtesy of ABC Science Online @

http://www.abc.net.au/science/articles/2008/10/14/2389526.htm?site=science&topic=latest

Image of the Day



Cretaceous period (note: Hesperonis is present in picture)

Monday, October 13, 2008

Sunday, October 12, 2008

Image of the Day


backpack gentoo, originally uploaded by R.W.W..

Climate Change Will Wreak Havoc on Penguins


Climate Change To Devastate Or Destroy Many Penguin Colonies

ScienceDaily (Oct. 12, 2008) — Half to three-quarters of major Antarctic penguin colonies face decline or disappearance if global temperatures are allowed to climb by more than 2°C.

A new WWF report – 2°C is Too Much – shows that the colonies of 50 per cent of the iconic emperor penguins and 75 per cent of the Adélie penguins are under threat.

Climate change models forecast that a 2°C temperature rise above pre-industrial level could be a reality in less than 40 years, producing a strong reduction in the sea ice cover of the Southern Ocean which is an essential nesting and feeding ground for Emperor and Adélie penguins.

A reduction in the sea ice is also likely to have a knock-on effect on the abundance of krill, which is a vital food source for penguins.

Juan Casavelos, WWF Antarctica Climate Change Coordinator said: “Penguins are very well adapted to living in the cold and extreme conditions of Antarctica, so the continued increase in global temperature and resulting loss of feeding areas and nesting zones for their chicks has already led to notable reductions in their populations.

“If temperatures increase by another two degrees these icons of the Antarctic will be seriously threatened.”

A rise in global average temperatures of 2°C is widely regarded as a threshold level for unacceptable risks of dangerous climate change. Many recent climate models forecast likely temperatures rises in excess of this.

2°C is Too Much was launched at the IUCN World Conservation Congress taking place this week in Barcelona, Spain.

The only way to significantly reduce the risks of climate change in Antarctica, as well as globally, is to substantially reduce greenhouse gas emissions.

WWF is calling for all nations to work together to agree on a new global deal that will succeed the Kyoto Protocol and tackle climate change beyond 2012.

This should include an obligation on developed countries to cut 25-40 per cent of their emissions by 2020 and 80-90 per cent by 2050, compared to 1990 levels.

WWF also proposes the establishment of a network of marine protected areas to reduce pressure on the species, and the implementation of precautionary management measures that ensure the future of the krill and finfish fisheries and all Southern Ocean species – including penguins – that are dependant on them.

Juan Casavelos said: “The predicted threat to Emperor and Adélie penguin populations is a clear incentive for the world to agree on a set of measures to reduce global emissions.

“It is imperative that the international community analyses all possible ways to limit climate change and improve the resilience of the penguin population.”

Need to cite this story in your essay, paper, or report?

MLA
World Wildlife Fund. "Climate Change To Devastate Or Destroy Many Penguin Colonies." ScienceDaily 12 October 2008. 12 October 2008 .

Friday, October 10, 2008

Image of the Day


Adelie penguins – Discovery Expedition, London, British Museum, 1907
to 1912.

Thursday, October 9, 2008

Image of the Day


Photograph by: Emily Stone
National Science Foundation

The diving habits and abilities of emperor penguins have been studied for several years by researchers based at the US base at McMurdo Sound Antarctica. A non-breeding group of juveniles are taken to a place about 15 miles away from open sea and kept in a corral known as "Penguin Ranch". A hole is cut for them through the sea-ice and as it is so far from any other holes in the ice, the penguins are obliged to return to where they came from.

Observations on their diving habits and times are taken and they are sometimes equipped with depth recording equipment to show how often and how deep they dive to. The penguins show no signs of harm or distress from this treatment. At the end of the season, the fence is taken down and the penguins wander off to resume their lives as normal.

Text courtesy of Cool Antarctica @

http://www.coolantarctica.com/gallery/penguins/emperor_penguin_8.htm

Wednesday, October 8, 2008

Image of the Day

Penguin Science and Dr. David Ainley



One of the reasons I began this blog was to have a coherent, intelligent, and reputable location that would contain as much science concerning penguins, as possible. As with most science, is does not exist in a vacuum. Obviously, biology takes the forefront when discussing penguins, but how about geology, paleontology, meteorology, and zoology? I want this gestalt snapshot of penguin research to include them all.

When another website comes along that includes those elements and that also involves cutting edge research, then I am extremely happy. Penguin Science is that place where one can spend hours reading the research, watching the videos, and taking a glance at all those adelie pictures. Dr. David Ainley heads the research there, and he has become one of the two people who are my personal heroes. The book cover to the side contains his fascinating research involving adelie penguins. Clicking HERE will take you to the page where you can order his book and also, download many of his research papers. There is also a dvd that is a two thumbs up visual exploration of how these folks do what they do and lots of footage on adelie penguins.

So, check out Penguin Science and bookmark it, as it is the leading site for education and enlightenment. This site should be totally supported by all penguin fans, for by what these folks do, they can help raise awareness to and help to solve the problems that otherwise, could eradicate those wonderful birds.

Climate Change Closes Future for Penguins




As many as 50 per cent of Emperor Penguin colonies are under threat from temperature increases in the Antarctic




WWF News Centre

Climate change to devastate or destroy penguin colonies



© WWF / Fritz PÖLKING
08 Oct 2008
Half to three-quarters of major Antarctic penguin colonies face decline or disappearance if global temperatures are allowed to climb by more than 2°C.

A new WWF report – 2°C is Too Much – shows that 50 per cent of the iconic emperor penguins and 75 per cent of the Adélie penguins are under threat.

Climate change models forecast that a 2°C temperature rise above pre-industrial levels
could be a reality in less than 40 years, producing a strong reduction in the sea ice cover of the Southern Ocean which is an essential nesting and feeding ground for Emperor and Adélie penguins.

A reduction in the sea ice will also have knock-on effects on the abundance of krill, which is a vital food source for penguins.

Juan Casavelos, WWF Antarctica Climate Change Coordinator said: “Penguins are very well adapted to living in the cold and extreme conditions of Antarctica, so the continued increase in global temperature and resulting loss of feeding areas and nesting zones for their chicks has already led to notable reductions in their populations.

“If temperatures increase by another two degrees these icons of the Antarctic will be seriously threatened.”

A rise in global average temperatures of 2°C is regarded as a threshold level for unacceptable risks of catastrophic climate change. Many recent climate models forecast likely temperatures rises in excess of this.

Risks to penguins were underlined this week, when hundreds of penguins were washed up on the Brazilian coast, thought to have been carried north on warmer ocean currents.

Environmentalists say it is not known why the penguins became stranded so far north, but suggest they could have been carried beyond their usual range by a flow of warm water.

The penguins were airlifted home, using a huge airforce cargo plane. Almost 400 that had strayed on to beaches, including Copacabana in Rio de Janeiro, were saved.

Onlookers cheered as the young Magellanic penguins were set free on a beach in southern Brazil and scampered into the ocean.

Experts hope a small group of older penguins released along with the young ones will help to guide them south to Patagonia.

The stranded birds were among nearly 1,000 penguins that have washed up on Brazil's north-eastern coast in recent months. The others have either died or were not healthy enough to send back.

While the global average temperature rise currently sits at 0.74 degrees, temperatures are rising much more rapidly at the poles. Temperature measurement in Antarctica has only been conducted with some precision for about 50 years, with one station showing a rise of 2.5 °C in that time, indicating that Antarctic temperatures may be rising at four times the global rate.

Rapid emissions reduction is the key to significantly reduce the impacts of climate change in Antarctica.

WWF is calling for all nations to work together to agree on a new global deal that will succeed the Kyoto Protocol and tackle climate change beyond 2012.

This should include an obligation on developed countries to cut 25-40 per cent of their emissions by 2020 and 80-90 per cent by 2050, compared to 1990 levels.

WWF also proposes the establishment of a network of marine protected areas to reduce pressure on the species, and the implementation of precautionary management measures that ensure the future of the krill and finfish fisheries and all Southern Ocean species – including penguins – that are dependant on them.

Juan Casavelos said: “The predicted threat to Emperor and Adélie penguin populations is a clear incentive for the world to agree on a set of measures to reduce global emissions.

“It is imperative that the international community analyses all possible ways to limit climate change and improve the resilience of the penguin population.”

Also, at the website, there is a pdf file one can download that explains what happens when earth's tropospheric temperature reaches 2 degrees Celsius above pre-industrial levels... check it out.

Information is courtesy of the WWF @

http://www.panda.org/news_facts/newsroom/index.cfm?uNewsID=147341

Monday, October 6, 2008

Emperor Penguin Biology



Image courtesy of the US Antarctica program @
http://photolibrary.usap.gov/AntarcticaLibrary/PENGUIN_LIFECYCLE_H.JPG

So, What Happened with the Penguin Flipper?


Gene Expression In Alligators Suggests Birds Have 'Thumbs'

ScienceDaily (Oct. 6, 2008) — The latest breakthrough in a 120 year-old debate on the evolution of the bird wing was published in the open-access journal PLoS ONE, October 3, by Alexander Vargas and colleagues at Yale University, the University of Wisconsin-Madison and Yale Peabody Museum of Natural History.

Bird wings only have three fingers, having evolved from remote ancestors that, like humans and most reptiles, had five fingers. Biologists have typically used embryology to identify the evolutionary origin (homology) of structures; the three fingers of the bird wing develop from cartilage condensations that are found in the same positions in the embryo as fingers two, three and four of humans (the index, middle and ring fingers). However, the morphology of the fingers of early birds such as Archaeopteryx corresponds to that of fingers one, two and three in other reptiles (thumb, index and middle finger). The fossil record clearly shows that fingers four and five (ring and pinky finger) were lost and reduced in the dinosaur ancestors of birds.

Further, the lack of expression of the HoxD-11 gene in the first finger of the wing makes it most similar to finger one (the "thumb") of the mouse, consistent with comparative morphology. However, the mouse is only distantly related to birds; crocodilians, in turn, are bird's closest living relatives.

To see whether the evidence from mouse HoxD-11 expression held up, Vargas and colleagues, working at the lab of Gunter Wagner at Yale, have examined the expression of this gene in alligators; they found the expression to be, as in mice, absent only in finger one (the "thumb").

Developmental and evolutionary biologists are familiar with the phenomenon of homeotic transformations, in which one structure begins to develop at a different position within the body. A famous example is the case of the fruitfly mutant antennapaedia, which develops legs on its head instead of antennae. The new work by Vargas et al. rekindles the hypothesis that a "hometic frameshift" occurred in the evolution of the bird wing, such that fingers one, two and three began to develop from the embryological positions of fingers two, three and four.

Journal reference:

1. Vargas et al. The Evolution of HoxD-11 Expression in the Bird Wing: Insights from Alligator mississippiensis. PLoS ONE, 2008; 3 (10): e3325 DOI: 10.1371/journal.pone.0003325

Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Need to cite this story in your essay, paper, or report?
MLA
Public Library of Science. "Gene Expression In Alligators Suggests Birds Have 'Thumbs'." ScienceDaily 6 October 2008. 6 October 2008 .

Sunday, October 5, 2008

Image of the Day

The Great Auk was once believed to be an ancestor of the penguin; however, that connection has now been shown to be false.

Saturday, October 4, 2008

Image of the Day


Ancient swimming bird cast, originally uploaded by mr_drew.

I would say this prehistoric bird was very closely related to the penguin.

Friday, October 3, 2008

Thursday, October 2, 2008

Image of the Day


Auckland Museum, originally uploaded by angry.badger.

Ancestor Day "Continues....



Science News

Mass Extinctions And The Evolution Of Dinosaurs

ScienceDaily (Sep. 30, 2008) — Dinosaurs survived two mass extinctions and 50 million years before taking over the world and dominating ecosystems, according to new research published this week.

Reporting in Biology Letters, Steve Brusatte, Professor Michael Benton, and colleagues at the University of Bristol show that dinosaurs did not proliferate immediately after they originated, but that their rise was a slow and complicated event, and driven by two mass extinctions.

“The sheer size of dinosaurs like Tyrannosaurus makes us think there was something special about these animals that preordained them for success right from the beginning,” Brusatte said. “However, our research shows that the rise of dinosaurs was a prolonged and complicated process. It isn’t clear from the data that they would go on to dominate the world until at least 30 million years after they originated.”

Importantly, the new research also shows that dinosaurs evolved into all their classic lifestyles – big predators, long-necked herbivores, etc. – long before they became abundant or diversified into the many different species we know today.

Brusatte added: “It just wasn’t a case of dinosaurs exploding onto the scene because of a special adaptation. Rather, they had to wait their turn and evolved in fits and starts before finally dominating their world.”

Dinosaurs originated about 230 million years ago and survived the Late Triassic mass extinction (228 million years ago), when some 35 per cent of all living families died out. It was their predecessors dying out during this extinction that allowed herbivorous dinosaurs to expand into the niches they left behind.

The rapid expansion of carnivorous and armoured dinosaur groups did not happen until after the much bigger mass extinction some 200 million year ago, at the Triassic-Jurassic boundary. At least half of the species now known to have been living on Earth at that time became extinct, which profoundly affected life on land and in the oceans.

Historically the rise of the dinosaurs has been treated as a classic case in which a group evolves key features that allow it to rapidly expand, fill many niches, and out-compete other groups. But Professor Benton said the story isn’t so simplistic: “We argue that the expansion of the dinosaurs took up to 50 million years and was not a simple process that can be explained with broad generalizations.”
Adapted from materials provided by University of Bristol.

Need to cite this story in your essay, paper, or report?
MLA
University of Bristol. "Mass Extinctions And The Evolution Of Dinosaurs." ScienceDaily 30 September 2008. 2 October 2008 .

Myth busted? Pterosaurs 'too heavy to fly'


Sci. & Tech.
Myth busted? Pterosaurs 'too heavy to fly'

London (PTI): Pterosaurs, the ancient reptiles which could grow to the size of small aircraft, were too heavy to fly even with their massive wings, a new study has claimed.

Pterosaurs, which existed alongside the dinosaurs and vanished along with them around 65 million years ago after a possible asteroid impact, were often known as the terror of the prehistoric skies.

Now, scientists in Japan have found evidence that the pterosaurs struggled to get off the ground because they could not flap fast enough to create the thrust that's required to keep their enormous bulk airborne.

According to lead scientist Katsufumi Sato, the largest animal capable of soaring across the sky unaided could have weighed no more than 40 kg or the size of a labrador dog, 'The Daily Telegraph' reported.

They have based their findings on an analysis of data on the flight of 28 birds from five large species, including the world's biggest, the wandering albatross. They calculated that it was physically impossible for them to stay aloft.

In fact, Prof Soto and colleagues travelled to the Crozet Islands -- halfway between Madagascar and Antarctica -- and attached accelerometers, devices the size of AA batteries which measure thrust, to the wings of the birds.

Unlike turkeys or bustards, whose short wings are good for quick take-off but not for soaring, these larger birds fly long distances using dynamic soaring -- they ride changing wind currents without moving their wings.

But when the wind dies down, or blows at a constant speed, they have to flap or be pulled down by air resistance and gravity. The maximum speed a bird can flap is limited by its muscle strength and decreases for heavier species with longer wings.

Prof Sato concluded that animals heavier than 40 kg would not be able to flap fast enough to stay aloft. And, this would explain why the wandering albatross weighs only 22 kg.

"A bird weighing close to 40 kg would be incredible unstable and would not have a safety margin to fly in bad weather."

Story courtesy of The Hindu News@

http://www.hindu.com/thehindu/holnus/008200810021631.htm

Image courtesy of Flickr @

http://flickr.com/photos/markwitton/1386125619

Antarctic Waters Were Once Warm


BBC NEWS
Antarctic waters were 'once warm'


New research suggests Antarctica 40 million years ago had a warmer climate than previously thought with little or no ice.

Cardiff University researchers analysed fossils from sediments on a cliff in South Island, New Zealand.

New Zealand was around 1,100km further south 40 million years ago, so was much closer to Antarctica.

The surface sea temperature would have been around 23-25C (73-77F), higher than off the South African coast today.

The research has been published in the journal Geology this week by a team of scientists from the university.


ANTARCTIC FACTS
Antarctica is the coldest place on Earth
98% is covered by ice
Antarctica is divided in two by the Transantarctic Mountains
The highest peak is 4,892 metres
Antarctica is home to more than 70 lakes that lie below the continental ice sheet
Emilio Marcos Palma was the first person born on the Antarctic mainland, at Base Esperanza in 1978

"This is too warm to be the Antarctic water we know today," said Cat Burgess, who led the study.

"And the sea water chemistry shows there was little or no ice on the planet."

The research came from analysis of fossils of marine micro-organisms found in rocks.

"Because the fossils are so well preserved, they provide more accurate temperature records," said Miss Burgess.

"Our findings demonstrate that the water temperature these creatures lived in was much warmer than previous records have shown."

She added that several studies had suggested that greenhouse gases 40 million years ago were similar to those forecast for the end of this century and beyond.

This could provide clues about how temperatures may change in the future.

"Our work provides another piece of evidence that, in a time period with relatively high carbon dioxide levels, temperatures were higher and ice sheets were much smaller and likely to have been completely absent," she said.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/uk_news/wales/south_east/7530702.stm

Published: 2008/07/30 11:09:45 GMT

© BBC MMVIII

Wednesday, October 1, 2008

Meat Eater 'Saur Had Birdlike Breathing System

From:
http://www.sciencedaily.com/releases/2008/09/080929212931.htm

Meat-eating Dinosaur From Argentina Had Bird-like Breathing System
enlarge




Flesh rendering of the predator Aerosteon with the body wall removed to show a reconstruction of the lungs (red) and air sacs (other colors) as they might have been in life. (Credit: Drawing: Todd Marshall c 2008, courtesy of Project Exploration)

ScienceDaily (Sep. 30, 2008) — The remains of a 30-foot-long predatory dinosaur discovered along the banks of Argentina's Rio Colorado is helping to unravel how birds evolved their unusual breathing system.

University of Michigan paleontologist Jeffrey Wilson was part of the team that made the discovery, to be published Sept. 29 in the online journal Public Library of Science ONE and announced at a news conference in Mendoza, Argentina.

The discovery of this dinosaur builds on decades of paleontological research indicating that birds evolved from dinosaurs.

Birds have a breathing system that is unique among land animals. Instead of lungs that expand, birds have a system of bellows, or air sacs, which help pump air through the lungs. This novel feature is the reason birds can fly higher and faster than bats, which, like all mammals, expand their lungs in a less efficient breathing process.

Wilson was a University of Chicago graduate student working with noted dinosaur authority Paul Sereno on the 1996 expedition during which the dinosaur, named Aerosteon riocoloradensis ("air bones from the Rio Colorado") was found. Although the researchers were excited to find such a complete skeleton, it took on even more importance as they began to understand that its bones preserved hallmark features of a bird-like respiratory system.

Arriving at that understanding took some time. Laboratory technicians spent years cleaning and CT-scanning the bones, which were embedded in hard rock, to finally reveal the evidence of air sacs within Aerosteon's body cavity. Previously, paleontologists had found only tantalizing evidence in the backbone, outside the cavity with the lungs.

Wilson worked with Sereno and the rest of the team to scientifically describe and interpret the find. The vertebrae, clavicles, and hip bones bear small openings that lead into large, hollow spaces that would have been lined with a thin layer of soft tissue and filled with air in life. These chambers result from a process called pneumatization, in which outpocketings of the lungs (air sacs) invade the bones. Air-filled bones are the hallmark of the bellows system of breathing in birds and also are found in sauropods, the long-necked, long-tailed, plant-eating dinosaurs that Wilson studies.

"In sauropods, pneumaticity was key to the evolution of large body size and long necks; in birds it was key to the evolution of a light skeleton and flight," Wilson said. "The ancient history and evolutionary path of this feature is full of surprising turns, the explanations for which must account for their presence in a huge predator like Aerosteon and herbivores like Diplodocus, as well as in a chicken."

In the PLoS ONE paper, the team proposes three possible explanations for the evolution of air sacs in dinosaurs: development of a more efficient lung; reduction of upper body mass in tipsy two-legged runners; and release of excess body heat.

Sereno, a National Geographic Explorer-in-Residence, said he is especially intrigued by heat loss, given that Aerosteon was likely a high-energy predator with feathers but without the sweat glands that birds possess. At approximately 30 feet in length and weighing as much as an elephant, Aerosteon might well have used an air system under the skin to rid itself of unwanted heat.

In addition to Sereno and Wilson, coauthors of the PLoS ONE article include Ricardo Martinez and Oscar Alcober of the Universidad Nacional de San Juan, Argentina, David Varricchio of Montana State University and Hans Larsson of McGill University. The expedition that led to the discovery was supported by the National Geographic Society and The David and Lucille Packard Foundation.
Adapted from materials provided by University of Michigan.
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MLA Citation
University of Michigan. "Meat-eating Dinosaur From Argentina Had Bird-like Breathing System." ScienceDaily 30 September 2008. 1 October 2008 .

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