 |
|
Hippo ancestry disputed
March 19, 2009Researchers rebut family tree involving hippos, whales and pigs in this week's Nature
Hippos spend lots of time in the water and now it turns out (or researchers argue), they are the closest living relative to whales. It also turns out, the two are swimming in a bit of controversy.
Jessica Theodor, an associate professor in the Department of Biological Sciences at the University of Calgary, and her colleague Jonathan Geisler, associate professor at Georgia Southern University are disputing a recent study that creates a different family tree for the hippo.
That research was published in Nature in December 2007 by J. G. M. Thewissen, a professor at Northeastern Ohio Universities College of Medicine, and his colleagues. Thewissen says that whales are more closely linked to an extinct pig-like animal, often known as India's pig or Indohyus, while hippos are closely related to living pigs.
But this isn't accurate according to Theodor.
"What Thewissen is saying is that Indohyus is the closest relative of whales - and we agree. Where we think he is wrong, is that he is saying that that hippos are more closely related to true pigs than they are to whales," says Theodor. "This contradicts most of the data from DNA from the last 12 or 13 years. Those data place hippos as the closest living relative to whales."
She says Thewissen did not use DNA evidence, instead used fossil evidence alone to create a family tree and reach the conclusion that hippos have more in common with pigs than whales.
"And the reason their tree is so different is simple: by excluding all the DNA information they left out all the data that shows a strong relationship between whales and hippos."
Theodor's rebuttal of Thewissen's work will appear in Nature on Thursday, March 19.
The controversy began after the new fossil of Indohyus, was discovered and written about by Thewissen and his group. This animal lived around 48 million years ago, lived in the water and fed on land.
When biologists study family trees, they traditionally rely on morphology, in other words, the shape of bones. More recently, the DNA revolution means that scientists can use DNA data as another tool to reconstruct family trees, but DNA data can't be used all the time because DNA is not available for most fossils.
"In order to get the best understanding, researchers combine the two sources of data in a single analysis. But what Thewissen and his group did, was leave one of the major ones out," says Theodor.
Before the widespread use of DNA data, hippos had been thought to be closely related to pigs, but DNA data show that whales are closely related to hippos. Geisler and Theodor argue that leaving out the DNA data not only ignores important information, it implies that the evolution of swimming evolved independently in hippos and whales, when it may have evolved only once in a common ancestor.
University of Calgary
That research was published in Nature in December 2007 by J. G. M. Thewissen, a professor at Northeastern Ohio Universities College of Medicine, and his colleagues. Thewissen says that whales are more closely linked to an extinct pig-like animal, often known as India's pig or Indohyus, while hippos are closely related to living pigs.
But this isn't accurate according to Theodor.
"What Thewissen is saying is that Indohyus is the closest relative of whales - and we agree. Where we think he is wrong, is that he is saying that that hippos are more closely related to true pigs than they are to whales," says Theodor. "This contradicts most of the data from DNA from the last 12 or 13 years. Those data place hippos as the closest living relative to whales."
She says Thewissen did not use DNA evidence, instead used fossil evidence alone to create a family tree and reach the conclusion that hippos have more in common with pigs than whales.
"And the reason their tree is so different is simple: by excluding all the DNA information they left out all the data that shows a strong relationship between whales and hippos."
Theodor's rebuttal of Thewissen's work will appear in Nature on Thursday, March 19.
The controversy began after the new fossil of Indohyus, was discovered and written about by Thewissen and his group. This animal lived around 48 million years ago, lived in the water and fed on land.
When biologists study family trees, they traditionally rely on morphology, in other words, the shape of bones. More recently, the DNA revolution means that scientists can use DNA data as another tool to reconstruct family trees, but DNA data can't be used all the time because DNA is not available for most fossils.
"In order to get the best understanding, researchers combine the two sources of data in a single analysis. But what Thewissen and his group did, was leave one of the major ones out," says Theodor.
Before the widespread use of DNA data, hippos had been thought to be closely related to pigs, but DNA data show that whales are closely related to hippos. Geisler and Theodor argue that leaving out the DNA data not only ignores important information, it implies that the evolution of swimming evolved independently in hippos and whales, when it may have evolved only once in a common ancestor.
University of Calgary
Hippos Current Events and Hippos News RSSGetting a leg up on whale and dolphin evolution
When the ancestors of living cetaceans-whales, dolphins and porpoises-first dipped their toes into water, a series of evolutionary changes were sparked that ultimately nestled these swimming mammals into the larger hoofed animal group.
Republic of Congo announces two massive protected areas
The Minister of Forestry Economy of the Republic of Congo announced today plans to create two new protected areas that together could be larger than Yellowstone National Park, spanning nearly one million hectares (3,800 square miles).
Elephants, large mammals recover from poaching in Africa's oldest national park
A recent wildlife census conducted in Virunga National Park in the Democratic Republic of Congo (DRC) revealed that several species of large mammal are now recovering from a decade of civil war and rampant poaching.
How ancient whales lost their legs, got sleek and conquered the oceans
When ancient whales finally parted company with the last remnants of their legs about 35 million years ago, a relatively sudden genetic event may have crowned an eons-long shrinking process.
Global warming dramatically changed ancient forests
The migration of subtropical plants to northern climates may not be too far-fetched if future global warming patterns mirror a monumental shift that took place in the past.
Even Babies Can Have Optical Illusions
At the tender age of five months babies can be fooled by complex information about distances in drawings involving perspective, psychologists from the University of Bonn have shown. They fixed two rubber figures onto a picture on which a chessboard pattern appeared to be receding away from the babies. The babies then tried to grab the toy which seemed nearer to them because of the information on distance implied by the drawing. This effect was even noticed in some cases in five-month-old children. Previously most experts had assumed that babies cannot decipher data on distance which are based on perspective until much later.
Why Sloths Do Not Sleep Upside Down
Several mammal species other than ruminants and camels have a multi-chambered forestomach - kangaroos, hippos, colobus monkeys, peccaries, sloths - but they do not ruminate. As studies on the digestive physiology of these species are largely missing, it is generally assumed that their forestomach functions in the same way as that of ruminants, the most prominent characteristic of which is the selective retention of larger particles. However, retaining larger particles (which are more difficult to digest due to their unfavourable surface:volume-ratio) only makes sense if you can chew on them again, i.e. ruminate, and thus reduce their size. In rodents and other small hindgut-fermenting herb
Madagascar`s lost wilderness @ the London `Catastrophes` conference
In the last 2000 years Madagascar has lost its entire endemic megafauna. This includes giant lemurs, pygmy hippos, elephant birds, and giant tortoises. This loss is the planet`s most recent prehistoric extinction event affecting a region with continental-scale diversity.
Decades of accumulated change court ecosystem catastrophe
Subjected to decades of gradual change by humans, many of the world’s natural ecosystems – from coral reefs and tropical forests to northern lakes and forests – appear susceptible to sudden catastrophic ecological change, an international consortium of scientists reports Thursday October 11 in the journal Nature. “Models have predicted this, but only in recent years has enough evidence accumulated to tell us that resilience of many important ecosystems has become undermined to the point that even the slightest disturbance can make them collapse,” said Marten Scheffer, ecologist at Wageningen University in the Netherlands and the lead author of the Nature paper.
More Hippos Current Events and Hippos News Articles
 |
HIPPO LOVER PARKING sign * st animal africa by Texsign HIPPO LOVER PARKING ONLY sign. A BRAND NEW sign!! Made of thick aluminum and tough vinyl lettering and grahics, this sign is 12in. wide and 18in. tall, just like official signs. Made to be installed outdoors it is nice enough to display indoors. Comes with holes pre-punched for quick and easy installation, corners are rounded. Buyer to pay $7.00 shipping anywhere in the USA, others contact seller for shipping cost. Money orders, cashiers checks, personal checks, or cash accepted. |
 |
Hungry Hungry Hippos by Hasbro Games Down by the river in a shady grove, live the Hungry Hungry Hippos. There's HoneyPotamus (who loves anything sweet), VeggiePotamus (who loves all things green), PickyPotamus (who's very, very picky), and his big brother BottomlessPotamus (who isn't picky at all!). Come on down to the riverbank and join the Hungry Hungry Hippos for a gobblin' good time. The player whose hippo munches the most wins! This heritage game with its frenetic, colorful gameplay is a recognizable favorite that always leaves kids hungry for more! |
 |
Hungry Hungry Hippos by Hasbro These four hungry hippos want to munch a bunch of marbles! The faster you press their tails, the more marbles they try to chomp! If your hippo gobbles the most, you win! For 2 to 4 players. Game includes: Hippo game base, 4 Hippo heads, 4 levers, label sheet, 20 marbles, instructions. Color of parts may vary. |
 |
Miniature Dashboard Hula Doll - Hula Hippo by KC Hawaii |
 |
Critter Magnifier (Hippo) by LightWedge Bring a little fun to your desk with the Critter Magnifier collection. Each critter magnifies 3X and is shatter-resistant. Available in three playful designs - collect them all! |
 |
Plush Standing Hippo 14" by Fiesta Surface Washable |
 |
Crystal Hippo 2.75" #132 by Crystal Florida This will make a wonderful gift for that special someone that you love so much. Add a touch of elegance and sparkle with a lighted rotary crystal stand (sold separately) which will illuminate this wonderful crystal gift. This is a perfect gift for the Modern 3rd Anniversary or the Traditional 15th Anniversary. |
 |
The Hiccuping Hippo by Keith Faulkner (Author) Poor Hippo has a horrible case of the hiccups. All of his friends think they know the perfect cure, but nothing seems to work. Hippo's hiccups just keep getting worse! Only when the animals put their heads together do they find the right solution, a cure that Hippo&150and young readers&150will never forget. With bright, bold pop-ups and a surprise ending, here is another wildly funny book from the bestselling creators of The Wide-Mouthed Frog. |
 |
Hippo for Christmas Sound 2009 Hallmark Ornament by Hallmark |
 |
Mullins Square Baby Costume, Hippo Gray by Mullins Square This hungry, hungry hippo is ready forsome halloween candy! This adorable hippo baby costume comes with a grey body and yellow tummy. The hat is in the shape of a hippo head! |
| © 2009 BrightSurf.com |