Clonal grove of trees considered oldest and heaviest living organism
Aspen grove might be clones
Courtesy Al_HikesAZ
I wrote about Earth's tallest, biggest, and oldest trees about four years ago. This week Wired Science had a wonderful gallery of photos and information about Earth's oldest trees.
One of them, Pando, is a 105-acre colony is made of genetically identical trees, called stems, connected by a single root system. This organism is believed to be 80,000 years old (and maybe a million) and weighs 6,615 tons, making Pando the heaviest living organism on earth.
Oldest and largest organism debate
You can read a debate about how other organisms might be larger and older here.
Other candidates for oldest or heaviest living organisms include the possibly larger fungal mats in Oregon, the ancient clonal Creosote bushes, and strands of the clonal marine plant Posidonia oceanica in the Mediterranean Sea.
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Birds of a feather...: This avian gynandromorph exhibits hen traits on its right side, and rooster traits on its left side, and is giving scientists insight into sex development in birds and other animals.
Courtesy Roslin Institute, University of EdinburghI must not have been paying attention lately because it appears there are some real bizarre chickens out there that are half rooster and half hen. I don't mean a jumbled mix where a bird exhibits some hen characteristics here and a couple rooster traits there – no, these are barnyard oddballs where one side is a female, and the other side is a male. It’s as if someone sliced a bird of each sex smack dab down the middle and sewed the two different halves together. A real, feathered chimerical freak show. These natural anomalies (known as gynandromorphs) appear in other life forms and have apparently been around for centuries.
Anyway, new research out of the University of Edinburgh’s Roslin Institute indicates that differences in male and female chicken cells - rather than hormones triggering genes – play a major role in determining sexual development in birds.
“This research has completely overturned what we previously thought about how sexual characteristics were determined in birds. We now believe that the major factors determining sexual development are built into male and female cells and derive from basic differences in how sex chromosome genes are expressed. Our study opens a new avenue for our understanding of sexual development in birds.” - Dr Michael Clinton
With mammalian development – including humans – after the two gamete cells (sperm and ova) fuse, the zygote’s somatic cells begin to grow and develop into whatever body plan it’s forming. The embryo remains sexually indifferent until certain genes switch on and sex-determining hormones are secreted. And for a long time it was thought all vertebrates developed in this same manner. But it looks like birds follow a completely different plan of action. Avian somatic cells don’t wait to get their cue from the gonads, and seem to already “know” their own sexual identity before any sex-determining hormones are secreted.
Named cell autonomous sex identity (CASI), the phenomenon runs counter to the prevailing ideas of development of sexual traits in birds, and explains why a gynandromorph can display female traits on one side and rooster traits on the other in the same bird. The male or female cells are dominant on the respective sides.
“It also means we must now reassess how this developmental process occurs in other organisms. There is already some evidence that organs such as the heart and brain are intrinsically different in males and females and birds may provide a model for understanding the molecular basis for these gender differences.” – Dr. Michael Clinton
The findings which appeared in the journal Nature, could also lead to answering why one gender is predisposed to certain diseases while the other isn’t. But whether they’ll be able to explain why gynandromorph chickens make the best fighting birds in cockfights is another question.
SOURCES and LINKS
Roslin Institute release
More about gynandromorphs
More about gonads
Sciencemag.org story
Asteroid found guilty of killing dinosaurs!!
in Earth and Space Science, Life Science, and Biological Populations Change Over Time
What sent the dinosaurs packing?: The number one suspect, a gigantic asteroid, has finally been convicted of the crime.
Courtesy Mark RyanAfter studying all available evidence and listening to alternative theories (and despite no eyewitnesses), a panel of 45 international scientists has decided it was a huge asteroid that killed all the non-avian dinosaurs some 65 million years ago.
The asteroid, described as a 7 mile-in-diameter chunk of space rock, has been the prime suspect in the ruling reptile’s demise ever since scientists Luis Alvarez and his son Walter first identified a one-inch layer of iridium in Late Cretaceous-age rock exposures throughout the world. The layer was located exactly at the point in the rock record where the Cretaceous period ended, and the Tertiary period began (K-T boundary). 
Smoking gun for dinosaurs' demise: K-T Boundary with 1-inch iridium layer (arrow) exposed 10 miles west of Trinidad, Colorado. The element iridium is very rare on Earth but concentrated in meteors and comets. The same iridium layer is found in several exposures around the world, and corresponds in age with the Chicxulub meteor crater in Mexico's Yucatan Peninsula. The layer marks the end of the Cretaceous era, and no non-avian dinosaur remains have ever been found above the boundary. The coal layers above and below the iridium suggests a swampy environment when the layer was laid down in this area of Colorado.
Courtesy Mark RyanThey predicted a meteor impact crater of the same age would be found as the source of the iridium since the element is rare on Earth but common in outer space. Then in 1990 their predictions were verified when the Chicxulub impact crater was discovered in Mexico.
Although the impact site was mostly submerged off the north coast of the Yucatan Peninsula, samples taken from it dated to the end of the Cretaceous period. This and other corroborating evidence helped bolster the killer asteroid hypothesis as the primary theory for the extinction event that wiped out 70-75 percent of life on Earth including non-avian dinosaurs, and other large reptiles. The asteroid is estimated to have slammed into Earth traveling 10 times faster than a rifle bullet, and released the energy of a billion atomic bombs. The impact instantly vaporized a large area of terrain, and sent an explosion of dust and rocky debris up into space, much of which fell back into the atmosphere in a fiery rain. It left a crater 110 miles across, and a cloud of dust circling the planet for weeks. The diminished sunlight would have disrupted the environment severely, including the food chain. Mammals and other smaller creatures were able to survive across the boundary and flourish in later periods.
But not everyone was convinced by the evidence. Other causes for the mass extinction, such as extreme volcanism in India, falling sea levels, disease epidemics, and even fungal infection were all tossed around as possible culprits.
But in the end it seems the evidence implicating the asteroid in the K-T* extinction event was just too strong, and after much deliberation, the impact has been determined as the official cause of death. The panel published its decision in the latest issue of Science.
*“K-T” stands for Cretaceous-Tertiary, however, use of the term Tertiary is being discouraged now, and the time span it occupied has been replaced with the Paleogene and Neogene periods. So a more proper, up-to-date term would be Cretaceous-Paleogene or K-Pg extinction event.
LINKS AND SOURCES
More about dinosaur extinction
BBC story
Impact theory counterview
Frozen in time: Unique fossil shows snake coiled among nest of dinosaur eggs and titanosaur hatchling.
Courtesy PLoS Biology
Diagram of fossil
Courtesy PLoS BiologyCheck out this amazing fossil showing the remains of a snake coiled around a nest of dinosaur eggs, including a nearby titanosaur hatchling. The fossil was found 26 years ago in northwestern India, and was originally thought to contain remains of eggs and baby dinosaur bones. But recent re-evalutions revealed some of the bones were actually those of a new species of snake named Sanajeh indicus. The incredible 67 million-year-old fossil is the first of its kind, and suggests that snakes preyed on dinosaurs, just as they prey on birds today. A newly hatched titanosaur would have been easy pickings for the 11.5 foot S. indicus, but an adult titanosaur - which grew to more than 100 feet in length - would have been another story. Scientists think the unique Cretaceous fossil resulted from an ancient landslide that buried the snake just when it was about to go after its next meal. Here's a photo of the incredible fossil and along with a diagram of what it contains. You can read the whole story at PLoS Biology where the research has been published.
Nike's new prototype- the retro model: The running foot is soooo 2 million years ago, but you wait long enough and everything comes back.
Courtesy perpetualplumHave you ever run barefoot? It’s great! I’ve never really thought about why I like it, but some really cool biomechanics research coming out of Harvard suggests that there may be some evolutionary reasons for my enjoyment. Homo sapiens and our early ancestors have engaged in endurance running for more than a million years, and have done so with no shoes, or with minimal footwear (sandals, moccasins, etc.). The researchers wanted to know how these early humans (and some humans today, let’s not forget) were able to run comfortably and safely sans shoes. Daniel Lieberman, professor of human evolutionary biology at Harvard, and his crew found that barefoot runners land either on the balls of their feet or mid-foot (the balls of their foot and heel at the same time), while shod runners land on their heels, or heel-strike, to use the lingo. This makes sense when you look at the structure of our feet; our strong, high arch acts like a spring when we run, and this spring can only be loaded when we first land on our forefoot. It wasn’t until the 1970’s when running shoes came equipped with highly cushioned heels that it began to seem normal to run heel-to-toe. (Some research even suggests that not just running shoes, but all shoes are detrimental to our foot health)
With some super advanced equipment (Harvard undergrads are so lucky), Lieberman saw how much of an impact heel-striking causes. When you heel-strike, your foot comes to a dead stop, causing your foot and leg to have to absorb all of that kinetic energy (a force which is 2-3 times your body weight). When you land on your forefoot, however, some of that kinetic energy is converted into rotational energy as your foot goes from toe to heel. This is obviously much less jolting. The researchers hypothesize that heel-striking is the cause of a lot of running-related repetitive stress injuries, and by avoiding heel-striking, more runners could see less of these types of injuries.
If you want to try running barefoot (and I recommend), Lieberman cautions that you shouldn’t just jump into it (especially if it is February in Minnesota), but rather start slowly. Running barefoot uses different muscles and it takes a little while for your feet to get used to it if you’ve been a shod runner your whole life. Who knows, your feet may be your new favorite shoes.
What is it?: It's... ah... you know, whatever.
Courtesy ReytanRoll up your sleeves and prepare a glass of filtered water, Buzzketeers, because it’s time to learn about the Guinea worm. It’s time to learn about the Guinea worm… hard!
In case the title of this post didn’t spoil it for you already, or if your mother printed out the page but cut off the title, or in case your eyes just don’t read letters that big, the Guinea worm grows to be up to three feet long. Inside you. And even though everything that enters my body must first pass through flame, it still freaks me out.
The parasitic guinea worm, or dracunculiasis (which means “afflicted with little dragons”—you’ll see why in a second), was once found in 20 countries across Asia and Africa, but improved sanitary conditions have reduced its range to just 4 countries in Sub-Saharan Africa. Which is cool, because the Guinea worm is super gross and bad, but not good enough, because the Guinea worm is super gross and bad.
The worm works like this: little worm larvae swim around in puddles and ponds until they get eaten by teeny, tiny crustaceans called copepods (sort of like little shrimp). They live and grow inside the copepods until the copepods get swallowed by people drinking unfiltered water. (Just to be clear, this isn’t just any unfiltered water. If you’ve got electricity to power a computer to read this, there’s pretty much zero chance that there are any worm-carrying copepods in your water. If it came from a tap and not a puddle, you’re probably cool. And even if it came from a puddle, you’re probably still cool.) The copepods get dissolved in the drinkers’ stomach acid, but not the baby worms, which then move from the stomach to the abdominal cavity. There, the worms mate. The male worms die and get absorbed, but the female worms wriggle their way deeper into the body, and grow. And grow and grow. Until they’re about three feet long. They live inside their human host for a year, and then they form a blister somewhere on the surface of the person’s body. When the blister bursts, the female worm emerges just a little bit. The worm releases chemicals that cause the blister to have a very painful burning sensation, and when the host puts the affected area in water to cool it, the worm releases hundreds of thousands of worm larvae into the water, where the cycle can begin again.
As if that whole experience weren’t uncomfortable enough, the treatment isn’t a whole lot better. Because there’s no medicine for Guinea worm infection, the adult worm itself must be removed. The way to do that is to grab the exposed bit of the worm and wrap it around a twig or a piece of cloth, and then twisting the twig. But it has to be done slooooowly so as to not break the worm while it’s still inside your muscles—the process, which is said to be extremely painful, can take up to a month before the worm is fully removed. It’s thought that the ancient for medicine, a snake wrapped around a rod may have been inspired by this procedure.
So, you know… ouch, blech, ouch.
Becoming infected once confers no protection from getting infected again, so people can get Guinea worms over and over again, and in addition to being painful, the blister the worm creates can make the sufferer vulnerable to more dangerous infections.
The good news is that preventing infection is relatively simple; infected people shouldn’t wash in water that will be used for drinking, and simple filters can keep people from ingesting the copepods that carry the worm larvae.
President Jimmy “Billy who?” Carter’s non-profit organization, The Carter Center, has been working for the last 20 years to eradicate the parasite. Despite some pretty significant barriers, it is expected that dracunculialisis will be the second disease, after smallpox, to be completely eradicated through human efforts. (Here’s a recent article on that.)
From what I’ve read (and what the Carter Center says), it looks like humans are the Guinea worm’s only host. So it seems to me that eradicating the infection would cause the extinction of the species. Think about that for a second. Usually sciencey types are pretty much completely against driving other organisms to extinction. But it seems like this one… considering how it pretty much only makes life worse for people who are already dealing with some serious challenges… should maybe… maybe… go extinct? I mean, obviously, right? But try that one on for size; I bet you haven’t often said to yourself that you’re cool with something going extinct. It’s a strange experience.
(If you just can’t deal with it, Here’s a website devoted to saving the Guinea worm. It’s satire, but subtle enough that you could probably play along. But, um, remember that sometimes the Guinea worm emerges from the eyes or genitals of its host. Just saying.)
Ibex: Capra ibex
Courtesy Nino BarbieriA recent article in the Journal of Archaeological Science reminded me of the importance of the Scientific Method Often we hear new and exciting scientific theories that seem plausible, especially if these ideas are presented in prestigious journals. However, the beauty of the Scientific Method is its verifiability, whether or not the data can be recreated through repetitive testing (If we truly believed everything the first time, our budding young scientists would have nothing to do!)
Michael Campana from the University of Cambridge and colleagues from across the UK and Ireland recently ran a sequence of DNA tests on 18th and 19th century parchments made from animal skins in order to reveal the complexities of ancient parchment analysis. Parchment is one of the most valuable archaeological and historical artifacts that can be used to understand not only language and history, but DNA testing on it can reveal clues to animal population studies, animal husbandry, different historical animal breeds, and provenance (where the animal or skins originated from). In the case of the Dead Sea Scrolls, DNA testing on the parchment could reveal what type of animal was used and possibly where it came from, providing additional data for questions regarding who wrote the scrolls.
Campana and colleagues analyzed both mitochondrial and autosomal genetic data using stable isotope, genetic, phylogenetic and ion beam analysis. All samples were considered to be well preserved and ideal samples for accurate testing. All but one parchment produced multiple DNA sequences that matched several different species including cow, goat, sheep, and even human. In other words, a parchment assumed to be made from one individual of one species, gave conflicting results as more than one species or more than one individual. Of course it can be assumed the parchment was not made of human skin and therefore human genetic data must have came from handling and processing of the parchment, but parchments can also be contaminated in long-term storage or contact with each other. Testing results can also be skewed by glues and inks or other preparatory treatments used to improve the surface. All of these factors need to be considered when testing truly ancient parchment like the Dead Sea Scrolls.
Previous DNA test results from 2001 and 1996 on the Dead Sea Scrolls produced results pointing to a single species, either ibex (Capra ibex) or domestic goat. While these results may indeed be correct, the likelihood that the results were so exact, when testing such as Campana's and colleagues on better preserved and more recent parchment were so complex, questions the accuracy of the earlier DNA testing. Of course we must not forget, precious artifacts like the Dead Sea Scrolls can not be needlessly dissected to offer unlimited samples for DNA testing labs. But as, Campana states, “Improving our understanding of parchment's DNA content would allow us to develop a predictive model for sampling of historic manuscripts.”
So the messages for today, bravo for the Scientific Method and go see the Dead Sea Scrolls at the Science Museum! Learn the science, archaeology, history and more that surround these amazing artifacts. Ask questions like: did the scroll writers choose ibex for some scrolls over goat because they thought these documents were so special or was ibex as readily available as any other animal species? Did the handling of the scrolls by shepherds who supposedly found them contaminate the actual scroll DNA with sheep, human or goat DNA? What can DNA testing tell us about other ancient artifacts? As long as there are unanswered questions, no matter how small, there will be a need for scientific investigation; which is good news for our future scientists!
Naked Mole Rat: a mighty survivor both hairless and nearly blind
Courtesy MissTessmacherThe naked mole rat (Heterocephalus glaber) is truly one of the most remarkable animals on this earth. On average 3 inches long and weighing just over an ounce, one would not think this creature so high and mighty. However, its unusual traits have brought it under more medical scrutiny and established an ever increasing presence in research laboratories. Stories have rung for years about how the only species to survive a world Armageddon would be cockroaches and rats. My money is on the naked mole rat.
While called a rat, they are one of 37 species of mole rats globally and are more closely related to guinea pigs and porcupines than other Rodentia. Limited to parts of East Africa, they spend their lives under ground in a highly social commune of individuals, all governed by a queen. This is very similar to the eusociality seen in bees and ants. The queen is the only female to breed, with all other individuals serving as guards or workers. This unusual social life for a mammal in a colony can lead to fierce competitions among females when the old queen dies. It may take days or weeks of power struggle before life in the colony returns to normal.
In search of plant tubers for sustenance, they dig through the dirt with their teeth, developing a system of burrows that can carry on for miles. One of the naked mole rats remarkable features is its ability to survive in the high carbon dioxide environments of these tunnels. Their extremely low metabolic rate and high absorption of oxygen allow them to overcome the limitations of the cramped and congested space. Research has found that these mole rats are void of a pain transmitter called Substance P found in other mammals, and have an uncanny resistance to the oxidative stress of daily metabolism.
Researchers hope this could lead to new insights into the process of aging. Captive research colonies have had individuals live as long as 28 years. That is more than nine times as long as a research mouse! This longevity and unique durability lead even more scientists to consider the naked mole rat for captive study populations in the fight against other afflictions like stroke and cancer. If these superman-like traits haven’t given you a deeper appreciation for such a tiny hairless creature, perhaps you just need a clever ditty to sing their praises. Oh! …you so UGLY!
The Horse in Motion - Edward Muybridge: Eadweard Muybridge used photography to study animal movements - helping to answer a much debated question about whether or not all four of a horse's hooves left the ground at the same time during a gallop.
Courtesy Eadweard Muybridge
Scientists who study animal behavior have always had their work cut out for them. For one thing, animal behavior is complex, often involving tiny movements that are not visible to the naked eye. When studying the behavior of animals in groups, this can become even more complicated. Where do you begin to look for patterns? How do you make sense of what you see?
Another difficultly of studying animal behavior comes in designing research tools and experiments that don't interfere with the animal's natural environment. If you've ever tried to walk up to a bird or a squirrel, you know how hard it can be to get close enough to take a good look. The slightest movement or sound, even smells that humans can't smell, can put animals on edge, which might alter the way that they behave.
Over the years, recording equipment and new technologies have made it possible to study animal behavior in new ways. From the invention of photography, which allowed researchers to "freeze" animals and then to set those images in motion, studying how animals move - to newer kinds of imaging techniques that allow today's scientists to observe animal behavior in difficult situations, studying imperceptible changes in their bodies and brains as they move.
This article from The Scientist magazine details how a few researchers have overcome obstacles to studying animal behavior, including the story of a researcher who uses infrared heat-sensing cameras to study the flight trajectories of bats in Brazil. Using ordinary cameras, the necessary lights would disturb the natural behavior of the bats, but infrared cameras give researchers a glimpse of how a very large group of bats behaves at night.
This technology can also be used to study the collective group behavior of other creatures, from very large elephants, to butterflies. Check out the video below to see what bat researchers in Brazil saw when they put these cameras inside a cave.
Playing with fire: Delicious fire.
Courtesy eshermanThe people of the world wait, their breath held, their tongues clenched between their teeth, open cans of Fresca frozen halfway to their mouths. What do you mean, JGordon? Does soda give me cancer? Or not?
Well?!
Don’t worry, folks. It’s mostly “or not.” Or is it? Or not.
You may have heard (or read—I call it “hearing with your eyes”) that soft drinks might raise your chances of developing cancer. That was probably hard to hear (or read—I call “listening through your face-holes”), because I know you’re generally pro-soda, and generally anti-cancer, and you had been living your life in the hope that there would never be any conflict between the two. You can probably go on living like that, because it’s unlikely that pop is really going to give you cancer, but you should be aware that the world is a complicated place, and your soda and your cancer are sadly not excluded from the complications.
See, a the results of a study out of the University of Minnesota were recently published claiming that there seemed to be a link between the regular consumption of soft drinks (sugar-sweetened carbonated beverages) and a higher incidence of pancreatic cancer. Pancreatic cancer isn’t one of the fun cancers (like, ah, cancer of the… nothing). Although relatively rare, the three-year survival rate for people diagnosed with pancreatic cancer is about 30%, and the survival rate after five years is only 5%.
The study was based on a 14-year survey of 60,524 men and women in Singapore. Of that group, 142 people developed pancreatic cancer. Examining the lifestyles of those who did and did not develop cancer, the researchers found that people who drank two or more soft drinks a week (5 was the average) had an 87% increase in their chances of getting cancer. And because Singapore is a fairly wealthy country with good health care, the scientists think that the results could apply fairly well to western countries as well.
Oh, no! Right? I can’t give up RC Cola!
Well… eh. The thing to keep in mind is it’s all very complicated. Even if there was a direct link between sift drink consumption and pancreatic cancer, your chances of developing the cancer, even as a soda drinker, would still be very small. But, the thing is, there isn’t necessarily a direct link between the two; there’s an association here, but maybe not a causal link. That is, people who drink soda are more likely to get pancreatic cancer, but we don’t know it’s the soda that causes the cancer.
Soft drink consumption itself was associated with behavior like smoking and red meat consumption, so it’s difficult to say that it’s just the soft-drinking (as it were) that contributes to the increased cancer risk.
Researchers do think, however, that it’s possible that soda could be involved in a causal relationship with the cancer. The high sugar levels in soda probably contribute to increased insulin production and presence in the body, which may contribute to pancreatic cancer cell growth. The study also found, however, that there was no association between fruit juice consumption and pancreatic cancer, which sort of makes me wonder. Lots of fruit juice, after all, is very sugary (even if it’s not quite so sweet as most soda). So does it have something to do with the type of sweetener used? Most soda in this country is sweetened with corn syrup, but that’s not necessarily the case in other countries (see Coca Cola for an example), and there’s some debate as to how the body might react to different sweeteners.
Anyway, you aren’t completely taking your life in your hands if you finish that can of Fresca. (Fresca was probably a bad example, seeing as how it uses artificial sweeteners, and will probably give you a totally different kind of cancer.) You’re better off just taking the dip out of your mouth. It’s gross with Fresca anyhow.
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