Stories tagged Life Science
IllustrationCourtesy José-Manuel Benitos via Wikimedia CommonsFossil bones of two hominins
found in a cave in South Africa, could be those of a completely new species of human and fill in a gap in human ancestry. The remains, which were found within a yard of each other, are of an adult middle-aged female and juvenile male. Scientists speculate the two could even be a mother and its child, or at least members of the same tribe. Either way, they add valuable information to the very fragmentary record of human evolution.
Professor Lee Berger, lead researcher of the discovery, and a paleoanthropologist at the University of the Witwatersrand, says the remains are well preserved and between the two of them include a nearly complete skull, shoulder, arm, lower leg, and hand. The pelvis is well represented, too. The fossils were found in the Malapa cave not far from the Cradle of Humankind World Heritage Site near Johannesburg.
Named Australopithecus sediba, the new finds which are nearly two million years old, have characteristics common to both Homo (which includes us) and Australopithecus, early ape-like creatures, making it an important transitional fossil between the two genera. Photo link
“That period between 1.8 and just over two million years - is one of the most poorly represented in the entire early hominid fossil record. You're talking about a very small, very fragmentary record," said," lead scientist Lee Berger. "It's at the point where we transition from an ape that walks on two legs to, effectively, us.”
Berger is a professor of paleoanthropology at the University of the Witwatersrand in Johannesburg. First evidence of the find was actually found by his 9 year-old son, Matthew, who picked up a couple fossils bones, a collarbone and jawbone that had been discarded by miners. Further investigation led to the rest of the remains. Professor Berger had found the cave in 2008 using Google Earth.
Although clearly australopithecine in size and stature, and most closely similar to the species Australopithecus afarensis, the boy’s skull and jaw also contain features seen in the genus Homo, such as the facial structure (e.g. a slight bony chin), and the shape and size of the premolars and molars. The two creatures upper limbs were overly long, again a trait of Australopithecus, and means they were more-than-likely arboreal, and able to easily climb trees to seek refuge and food. But their pelvic structures share features found in the hips of the Homo genus, leaning toward more efficiency in walking or running. This means A. sediba fills in some of the gap between Australopithecus afarensis and Homo erectus. Professor Berger’s study appears in the journal Science.
Berger suspects the two A. sediba had been swept into the cave by a flash flood or some such disaster and buried fairly quickly. The dig site produced the remains of 25 other animals such as a horse, saber-toothed cat, wild dogs, and antelope. None of the remains appear to have been scavenged Fossils from two other hominid individuals were also found but have not yet studied.
LINKS
Article at Science.
Video at Science
Podcast at Science
More pictures at NatGeo
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Here's what we know...: But what happened before?Courtesy JGordonCheck this story out, Buzz-gumshoes: An Australian man has been sent to the hospital after a vicious wombat attack.
Interesting. Very interesting, eh, Buzzketeers? It sounds like our kind of story.
Here are the facts… as they have been reported so far:
-Bruce Kringle, 60, of Flowerdale, Australia, was stepping out of his home when he “felt something attack his leg.”
-The attacking party was a wombat, a badger-like marsupial.
-The wombat managed to knock Mr. Kringle off of his feet, and then climbed onto his chest and proceeded to savage the man for 20 or so minutes.
-An axe was within arm’s reach, and Mr. Kringle used it to kill the wombat.
-Mr. Kringle was then admitted to hospital with puncture wounds in his arms and legs.
-Wombats are generally docile creatures. This individual’s aggression might be explained by a irritating case of the mange.
I don’t know about y’all, but when I add all that up, I only produce one answer: WTF! (That stands for “Wombat Tale: False!”)
Here are some additional questions and considerations we must account for, before this case can be closed:
-Who is “Bruce Kringle”? Could he be the same person as Branson Kringle, the Special Forces soldier who came out of retirement to rescue a group of kidnapped missionaries in Myanmar, only to disappear once again when the mission was complete?
-Wombats can be several feet long, and weigh nearly 80 pounds, and they can achieve speeds of nearly 25 miles per hour. Without knowing the creature’s rate of acceleration, I can’t determine how much force it could have struck Mr. Kringle with (force=mass x acceleration), but it seems reasonable that the marsupial could have mustered enough force to knock the man over… except
-If Mr. Kringle “felt an attack” at his leg as soon as he stepped outside. This seems to imply that he was not immediately rammed by the attacking wombat. So… what? He was bitten, and then allowed the creature to back up and charge? While he was still so near to his front door? Hmm. How did Kringle end up on his back?
-Do something for me, Buzzketeers: tap your pointer fingers against each other. Continue to tap them for one whole minute. It feels like an awfully long time, doesn’t it? Now imagine that, instead of tapping your fingers for that minute, you were being attacked by something that looks like a wolf-sized hamster. And then multiply that length of time by twenty. That’s a long time to be attacked by a wolf-sized hamster (or by a wombat.)
-At what point did the axe appear within arm’s reach?
-Wombats, it seems, are actually not known to be particularly docile, especially when defending their territory from intruders.
-Mr. Kringle was, in fact, stepping out of his “caravan,” which is Australian for “RV.” He was living in the vehicle while his home was being rebuilt (it was destroyed in last year’s Black Saturday bush fires.)
Despite being an otherwise impeccably reliable newspaper, I feel like the Telegraph is withholding information from us.
It seems that Bruce may have been forced to temporarily move his caravan into wombat territory… but what was it about that day that made the wombat finally snap? How did Bruce get knocked over? And who gave Bruce the axe… only after allowing him to be attacked for twenty finger-tapping minutes?
I think someone wanted that wombat dead, and they manipulated trained-killer Bruce (aka, Branson) Kringle into pulling the trigger for them! The only remaining question is “who?”
BAM! How’s that for journalism?
A whole lotta shakin' goin' on!: Recent study reports toads can sense pre-seismic activities.Courtesy Bartosz Kosiorek via Wikimedia CommonsScientists aren’t sure why but a recent study reports that toads seem to be able to sense early warning signs of impending earthquakes. Back in 2009, biologist Rachel Grant from the UK’s Open University, in Milton Keynes noticed that common toads she happened to be studying in Italy suddenly abandoned their breeding grounds in droves just days before an earthquake struck nearby. Somehow, the amphibians sensed danger and stopped spawning between the first tremor and the last aftershock, even though their colony was located over 40 miles from the earthquake’s epicenter.
“Our findings suggest that toads are able to detect pre-seismic cues such as the release of gases and charged particles, and use these as a form of earthquake early warning system." – Dr Rachel Grant.
Similar strange behaviors have been witnessed in frogs during an earthquake in China , but Grant’s study is the first to document such odd amphibian behaviors, before, during, and after a temblor. The study appeared in the Journal of Zoology.
Cell Protein: Illustration of protein chain in the human cell.Courtesy Nicolle Rager and National Science FoundationScience Buzz has had a lot of articles on organ transplants over the years but a new report on liver transplants in children adds a new twist. Currently, severe organ damage or failure requires an organ transplant, preferably one from a donor with a histocompatibility similar to the recipient. In the case of severe liver failure in children, there is often no time to wait for a compatible organ and an incompatible organ is used requiring patients to take anti-rejection drugs (immunosuppression) for the rest of their life. In fact, 70% of all liver transplants require anti-rejection drugs.
Fortunately, the liver is one organ that has the ability to regenerate itself, especially in very young patients. The child patient is given a small section of donated liver, enough to allow the body to function properly, while leaving a small portion of their own liver intact. Hopefully, after a few years, the patient’s original liver will begin to repair and regenerate itself. The doctor can than gradually reduce the quantity of anti-rejection drugs, causing the body to slowly attack and destroy the donated liver segment. Eventually the patient will be removed from anti-rejection drugs completely, have their own liver back, and no signs of the temporary donated liver.
The liver is unique in its regenerative properties; for humans, that is. In other animals, such as amphibians, entire limbs can regenerate. Scientists are researching the role proteins play in cell regeneration in hopes that stimulating certain proteins in other organs of the body will encourage them to regenerate like the liver can.
Painting a new picture of human evolution: A finger bone found in a cave in southern Siberia may add another species to human evolution. (Painting by Charles R. Knight, AMNH).Courtesy Mark RyanThe bone of a single pinky finger found in a cave in southern Siberia may indicate a new branch in the human family tree. The find could show that besides Neanderthals and Homo sapiens, a third lineage of humans may have shared the ancient landscape of prehistoric Russia.
The piece of finger was found in Denisova cave located in Russia’s Altai mountains by scientists from the Russian Academy of Science. The bone was recovered from sediment layers that have also yielded signs of Neanderthals (Homo neanderthalensis) and modern humans (Homo sapiens). Radiocarbon dating set the age of the layers between 48,000 and 30,000 years old.
Scientists from Germany’s Max Planck Institute and others sequenced 16,569 base pairs of the finger bone’s mitochondrial DNA genome, and the results indicate the new hominen shared a common ancestor with both neanderthals and ancient modern humans sometime around a million years ago. The research team included Michael Shunkov and Anatoli Derevianko, the two Russian archaeologists who discovered the bone in 2008. The study appears in the journal Nature.
Further sequencing of DNA from cell nucleuses will be done next, and could help pinpoint the hominen’s exact origins. If confirmed, the discovery would mean four different species of humans (the 4th would be the Indonesian Hobbit Homo floresiensis) co-existed on Earth some 40,000 years ago.
SOURCE and LINKS
Science Now story
More about human evolution at Becoming Human
Radiocarbon dating
Clonal grove of trees considered oldest and heaviest living organism
Aspen grove might be clonesCourtesy 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.
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 fossilCourtesy 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.
