Sorry for the short notice, but this evening (May 5, 2011) at 6:30pm EDT (5:30 here in the Twin Cities) the American Museum of Natural History will present a live streamed discussion with famed paleoanthropologists Richard Leakey and Donald Johanson entitled Human Evolution and Why It Matters: A Conversation with Leakey and Johanson. Here's what the AMNH website says about it:
"Celebrating decades of groundbreaking exploration in East Africa, renowned paleoanthropologists Donald Johanson and Richard Leakey will share the stage to discuss the overwhelming evidence for evolution in the hominid fossil record and why understanding our evolutionary history is so important.
Known for such landmark discoveries as "Lucy" (Johanson) and "Turkana Boy" (Leakey), the work of these two scientists has produced much of the fossil evidence which forms our understanding of human evolution.
Looking back over careers spanning 40-plus years, these men will share the stories behind their monumental finds and offer a look at what's ahead in human evolutionary research.
Want to join in? Then go to the AMNH live streaming website around 5:30 CDT to catch this rare opportunity to watch two giants of the field of paleoanthropology exchange ideas and stories.
Courtesy 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.
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.
Courtesy Mark RyanHairs extracted from prehistoric hyena droppings in South Africa are most likely those of early humans that lived in the region around between 195,000 to 257,000 years ago. The human hairs - extracted from a nine-inch block of fossilized dung (coprolite) - are the most ancient yet known. Whether the ancient human had been attacked by the hyena or his remains scavenged by it is not known, but the discovery illustrates some of the difficulties that confronted early man. The findings have been accepted for publication in the Journal of Archaeological Science. In the meantime, click here to learn more.
Courtesy Public domainShells uncovered in two archaeological sites in southern Spain show evidence of pigments that scientists think were used by Neanderthals for rituals and body paint. The discovery, which is reported in Proceedings of the National Academy of Sciences, counters the popular notion that our prehistoric cousins were brutish numb-skulls.
Courtesy Mark RyanEver notice how some of your relatives have similar features just like those of some of your long dead ancestors? Perhaps you yourself are stuck with the same ears great-uncle Larry proudly displays in that sepia photo you have of him grinning in front of his brand new Model T.
Courtesy Open University (and Mark Ryan)You know, those Dumbo ears that look like a donation from the US Air Force.
Courtesy Open University (and Mark Ryan)But what about those family members who were evolving long before the advent of photography or even cave painting? Have you ever wondered what some of those ancient knuckle-draggers on the old family tree might have looked like?
Courtesy Open University (and Mark Ryan)Well, of course none of us (except the Terminator, Mr. Peabody, Marty McFly and JGordon) can actually travel back in time but we can do the next best thing, which is devolving via the miracle of modern technology.
Courtesy Open University (and Mark Ryan)How can we do that, you ask? It’s easy. Simply go here to Open University's Devolve Me site, upload a photo of yourself (or great-uncle Larry if you wish) and watch the image change into great-great-great-great-great-great-great-uncle Troglodyte,
For the sake of scientific inquiry I tried it myself and you can see the results on the right. Also, I tried to minimize the use of title prefixes in the photos (e.g. Great-great-great grandpa) since the actual titles would have gone on forever, and would have become really, really tiresome. I'm sure you get the picture.
Anyway, give it a try yourself. You just don't know what you'll find out about your ancestry. It may even answer those questions you have about your grandma's excessive back hair.
Hey, I think I have great-grandpa Australopithecus afarensis's eyes.
Courtesy spodzoneThe earliest fossil footprints showing evidence of modern human physiology and gait were found recently in northern Kenya. The 1.5 million year-old footprints are attributed to Homo erectus and display features similar to those of modern humans. The findings appear in the recent issue of Science.
Hundreds of new visitors came to our Buzz blog last week because their google search for "dinosaur mummy" pointed to my post titled Fossilized dinosaur mummy gets x-rayed. The internet buzz this week is about another dinosaur mummy. A hadrosaur, or duck-billed dinosaur, was discovered in 1999 by then-teenage paleontologist Tyler Lyson on his family's North Dakota property. It is not really a mummy (dried tissue), but a fossilized mummy (composed of rock).
"This specimen exceeds the jackpot," said excavation leader Phillip Manning, a paleontologist at Britain's University of Manchester."
"First the dinosaur body had to escape predators, scavengers, and degradation by weather and water. Then a chemical process must have mineralized the tissue before bacteria ate it. And finally, the remains had to survive millions of years undamaged." National Geographic
CT scans of the hadrosaur's fossilized muscle mass and computer modeling leads scientists to speculate that Dakota (the name given to this dinosaur mummy) could run 28 mph. This makes sense because hadrosaurs were being chased by the Tyrannosaurus rex which topped out at about 20 mph. Scientists warn that errors in computer modeling can be 50 per cent, though.
Most scientists refused to comment until their finds are published and undergo the scrutiny of peer review. Peggy Ostrom, who studies how organisms are related to each other, commented only in general terms.
"It's rare to find an articulated skeleton and even more so to find one with fossilized soft tissue,"
"If such finds show extraordinary preservation, they tempt us to wonder about the possibility of finding [unfossilized] biomolecules that might be remnants of the ancient organism."
The new report, by a paleoanthropologist from Germany’s Max Planck Institute of Evolutionary Biology, claims that there is no discernible connection of the extinction of our closest evolutionary relatives to extreme climate change.
Published recently in the journal Nature, the new research is centered on the comparing of evidence gathered from deep-sea core drillings in Venezuela, and from sediments found at Gorham’s Cave, in southern Gibraltar, thought to be one of the last places inhabited by Neanderthals on the European continent.
Using radiocarbon dates of 32,000, 28,000 and 24,000 (which are thought to mark the demise of our stocky prehistoric cousins), professor Katerina Harvati and her team compared them to past climate data gathered from the deep-sea drilling cores.
"The more controversial date of circa 24,000 years ago, places the last Neanderthals just before a major climate shift that would have been characterized by a large expansion of ice sheets and the onset of cold conditions in northern Europe,” according to Harvati, who co- authored the paper.
"But Gibraltar's climate would have remained relatively unaffected, perhaps as a result of warm water from the sub-tropical Atlantic entering the western Mediterranean,” she said
Converting a radiocarbon date into a calendar year can be tricky, but the team came up with a method to correlate estimated dates of the species’ demise with records of past climate. The first two dates, 32,000 and 28,000 didn’t correlate with any extreme climatic changes. And the earlier date, 24,000, corresponded to a paleoclimate occurring before the onset of colder, more severe weather in northern Europe, and ice-sheet advancement.
But even then the authors say that the onset was hardly a sudden ice-age, but rather the beginning of a 1000-year gradual change in climate.
So if a sudden shift in climate didn’t kill off the Neanderthals, what did? The question remains open.
"This eliminates catastrophic climate change as a cause for extinction, but this leaves a whole range of other possibilities,” Harvati said.