cafecuriosity

What Lies Beneath

Whether we like it or not, we see the world through a lens of expectation. There's a level of comfort to be found in the familiar. Take one of my passions - archaeology. When I think of archaeology, I think back to my trip along the Mayan trail - of majestic Mayan ruins peeking above the jungle canopy, or more recently, Athens' acropolis. Increasingly though, researchers are venturing underwater and they're finding remarkably preserved glimpses of our past. Earlier this year, researchers from London's Imperial College discovered a huge underwater valley carved into the chalk floor of the English Channel when rising water levels burst through the Weald-Artois chalk ridge and created today's English Channel. The canyon carved by the inundation is now preserved 50m below sea-level.  http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_19-7-2007-10-7-26   Image: Three dimensional sonar view of the erosion valley under the English Channel, Imperial College London

More recent events also submerged human settlements. Eight thousand years ago, there was a thriving Mesolithic site off the coast of the Isle of Wright. Marine archaeologists from the University of Southampton are bringing entire sections of the old seabed the 11 meters to the surface, revealing intact hearths, oceans and flint tools.  http://www.soton.ac.uk/mediacentre/news/2007/jul/07_90.shtml   Image: A diver working on the underwater site, Simon Brown, 2007

An Ice Age flood also played a neat trick on Michigan farmer Dennis Myllyla. Myllyla agreed to provide road fill from his silted up pond to the Michigan Department of Transportation. Unfortunately for Myllyla, dredging recovered a drift of logs, some 20' long and 2' in diameter, buried under 15' of soil. The logs are likely to be the remnant of one of the last Ice Age floods dating back 10,000 years before Lake Superior was formed. The hunt is on now to identify the species - early money is on a variety of elm. http://www.admin.mtu.edu/urel/news/media_relations/617/   Image: 1. Logs deposited by the last glacier in Michigan, 10,00o years ago, 2. The pond, ichigan Technological University

Chilling Out In Tasmania

How to explain human behaviour? Paleoanthropology is a perplexing science - perpetually teasing insights into the human condition thousands of years ago out of tantalising snippets of often conflicting facts. Take the case of the wanderings of Australia's aboriginal tribes in Tasmania during the last Ice Age. Paradoxically, the only evidence for aboriginal people dating to the Ice Age is located in the windiest, coldest southwest corner. At that time, Southwest Tasmania was one of the bleakest, coldest, most inhospitable parts of the continent, so why would tribes choose to gather in the coldest part of the country? One explanation according to Ian Gilligan a postgraduate researcher from the ANU is wind chill. Our tolerance for cold is a function of air temperature and wind. Caves are common in Tasmania's southwest which is riddled with steep gullies and ravines - providing protection from wind. Overlay Ice Age stone tools and bone needles with wallaby bones and you also have a picture of abundant winter game. Food and shelter are two of Maslow's physiological states in his 'Hierarchy of Needs'. I'm sure those Ice Age Aborigines managed the remaining needs caves or no caves!   http://www.abc.net.au/science/news/stories/2007/2039661.htm   Image: Southwest Tasmania, Ian Gilligan

Wrist Spin Delivers Another Hobbit Moment

For anyone familiar with the fracas over the 'Hobbit' fossils (Homo Floresiensis, a 3' tall, 18,000 year-old hominin skeleton discovered in a cave on Indonesia's Flores Island four years ago) the latest study by a team from the Smithsonian offers the potential for more fun! The team that discovered the 'Hobbit' firmly believed it was a new species of human. This claim was roundly refuted by many researchers who thought it much more likely that the unusual remains were due to either a growth deficiency or a skeletal pathology. Much unedifying and rancorous academic noise and posturing followed. The latest study starts with a different take on what defines us as human. Scientists tend to bang on about our big brains, use of language, skills with tools and even our complex social relationships. However, one facet of our anatomy which indisputably differentiates us from other apes and our early ancestors is our wrists! Wrist bones so I now know turn out to be complex bits of kit, making them quite useful in understanding the evolutionary relationships between living species and our fossil ancestors. Once again, it's a case of understanding that which unites us (modern humans and Neanderthals) and that which makes us different (early hominins, the great apes and Homo Floresiensis)! The 'Hobbit's' wrist is identical to those of African apes and early hominins and totally different to that of modern humans. The 'Hobbit' appears to be a new species of human as originally proposed, rather than a diseased individual as had been asserted. Over to the chorus of disbelievers!

Note: Analysing H. Floresiensis wrist structure depended on using advanced 3-D technology techniques developed only in the past few years at the Partnership for research in Spatial Modeling at Arizona State University (PRISM). The researchers who later analysed H. Floresiensis wrist structure happened to work there as graduate assistants where they learned to apply the technology.   http://uwnews.washington.edu/ni/article.asp?articleID=37120   Image: 1. Virtual comparison of wrist bones from a Chimpanzee, Hobbit and modern human, Human Origins Program, Smithsonian Institute/Matt Tocheri 2. Artists impression of H. Floresiensis,www.elbakin.net 3. Hobbit and modern human skulls, www.nationalgeographic.com

Flawed Inferences & Dubious Causality

At first blush, you wouldn't think there was much in common between contemporary management and a 2.5 million year old mystery. Well, as it turns out both suffer from our tendency to confuse our desire to find out about the world around us, with the facts we draw upon in arriving at our conclusions. For over 80 years, the mystery of how the Taung child met his/her fate has tantilised scientists. The fossil of the three and a half year old ape-like child was found in a cave in South Africa in 1924. Today, the Taung child (Australopithecus africanus) fossil is the most written about, studied and handled hominid skull discovered to date. Distinctive puncture wounds were quickly found on the skull - predations marks! In the minds of the scientists of the time, there was only one group of African predators - the big cats! It appeared a straightforward leap from predation marks to some ancestral lion or leopard. For decades, researchers accepted the Taung child fell prey to a big cat. One group of predators was either ignored completely or quickly dismissed - the raptors. Africa is home to big eagles. Until last year, their impact on primate development was considered negligible. Eagles weren't thought to be strong enough to lift primates the size of the Taung child. Then researchers W. Scott McGraw from Ohio state (go Buckeyes!) looked at modern monkey bones collected from underneath the nests of African crowned eagles. The monkey skulls had distinctive beak and talon puncture marks around the face and the eye sockets. The Taung child showed identical marks. It turns out eagles dismember their prey before taking the bits back to their nests - no need to lift an entire body! Not only is evidence from the study changing our view of the Taung child, it is changing the way scientists look at predator - prey dynamics overall. Now what about a quick look see at all those collections of hominid fossils scattered around the globe? Turns out our ancestors were part of the food chain, not the top of it! http://researchnews.osu.edu/archive/monkbird.htm  Image: 1. W.Scott McGraw with monkey skulls, 2. Eagle with Taung skull, www.msnbc.msn.com 3. Diana monkey skull with puncture wound, Jo McCulty, Ohio University

Faulty theories piled upon flawed inferences don't stop with the Taung child. When Duke University primatologist Elwyn Simons excavated the skull of a new species of primitive monkey Aegyptopithecus zeuxis in 1966, he expected it to have a large brain, based on comparisons with other fossils found at the site in Cairo, Egypt. An assumption that proved quite wrong! Fast forward to May, 2007. Elwyn's latest excavation produced an Aegyptopithecus zeuxis skull half the size of the 1966 specimen. Micro CT scanning revealed a brain even smaller than a modern lemur's. Oops - seems big brained monkeys and apes (like us) came along much later. Elwyn had been fooled by the significant differences in size between genders in some monkey species. The male Aegyptopithecus zeuxis weighed in at 10 - 11 lbs, while the females tipped the scales at a dainty 5.5 lbs. Rallying bravely, Elwyn proved you can't keep blind intuitive leaps down by conjecturing that the Aegyptopithecus zeuxis brain was sufficiently robust to manage the complex social relations found in monkey troops. Let's hope Aegyptopithecus zeuxis doesn't turn out to have been a loner! http://www.dukenews.duke.edu/2007/05/aegypto.html  Image: Elwyn Simons with 1966 male skull left and smaller female skull right, Megan Morr

Cracking Human Exclusivity

We humans have an interesting take on what defines our humanity. Traditionally, we've viewed certain traits as being uniquely human - namely our ability to; select, form and manipulate tools, exploit local resources effectively by shaping our environment, process and work raw materials for secondary applications, continued habitation of select sites and our habit of moving materials over often large distances to the point of consumption. Scientists have enjoyed bickering over which stream of humanity represents the point of origin of these aptitudes for years and now we have another candidate! Researchers from the Max Planck Society recently found evidence that West African chimps were using stone tools 4,300 years ago - smack in the Late Stone Age. This find pushes chimpanzee tools use back thousands of years and poses a very confronting question, "Did tool use descend from a common ancestor instead of arising independently amongst hominids and champs?" Intriguingly, tool usage amongst chimps is communicated socially, thus current tool usage represents a behavioural chain stretching back many, many generations. Cool! http://www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2007/pressRelease20070207/index.html

Image: Juvenile chimpanzee takes a nut from an anvil, Christophe Boesch

Our Evolving Identity

Identity is central to being human. Many of us take comfort from seeing our humanity as fixed, unchanging, done & dusted! Evolution happens to lesser species, so we don't much like the idea that evolution is happening to us. Now we're told humans continued to substantially evolve long after settling comfortably in Europe. Plus, horror or horrors they interbred with Neandertals and other humans as they settled. Now the discovery of the earliest human remains in Europe from Pe tera cu Oase (the Cave with Bones) in southwestern Romania suggests complex population dynamics were unleashed as human dispersed across Europe. Human experience it seems is never as simple or as black & white as theory suggests. The Oase 2 skull contains modern human features plus some bits which could be Neanderthal or even archaic traits from populations the modern humans met along the way. In the Paleolithic as now, it seems nothing about identity is simple or straightforward! http://www.bris.ac.uk/news/2007/5245.html

Image: Oase 2 cranium, Bristol University, Erik Trinkaus

Taxonomy's Dead Hand

  Last week we discussed the exciting discovery (if you're a palaeoanthropologist) of a nearly complete skeleton of a child in the Dikika region of Ethiopia. The remains were classified as Australopithecus afarensis (a hominid ancestor of humans) but the buzz was around what the Dikika child would reveal about human evolutionary development. Yet it didn't take long for nit pickers to emerge. Jeffrey Schwartz an anthropology professor at the U of Pittsberg and author of the 4 volume 'The Human Fossil Record' glided elegantly over the exciting bits to fuss over classification. In his view, all A. afarensis are from Laetoli, a site in Tanzania, so the new find cannot be A. afarensis. He did concede that the Dikika child could well be the first Ethiopian A. afarensis, or even a totally new taxon altogether. What is it with the dead hand of classification? What would you rather know, the new stuff we didn't know before, or what species the Dikika child belongs to? You'd think they could get on with unlocking the Dikika child's secrets without becoming sidetracked by the dead hand of a taxonomy fetish! For the gory detail of a dull debate, go to: http://mac10.umc.pitt.edu/m/FMPro?-db=ma&-lay=a&-format=d.html&id=2640&-Find

Image: The Dikika Research Project site, Max Planck Institute

A Precocious 3 Year Old

Our ancestors exert a mysterious hold over our imagination. So, the journal Nature dropped a bombshell on paleoanthropology in announcing the discovery in the Dikika area of north-eastern Ethiopia of a near complete fossilised skeleton of 'Selam' (peace in Amharic), a 3.3 million year old juvenile Australopithecus afarensis. The discovery includes a hydroid bone, ribs, spinal column, shoulder blades and collar bones - largely missing from previous finds. Yet they didn't come easily. Encased in solid sandstone, Selam, discovered in 2000, took four years to excavate in the field. Then sandstone sediment had to be removed grain by grain from the fossils using dental probes.  Who said curiosity isn't resilient? As usual there are lots for scientists to squabble over. The femur, tibia and foot show Selam walked upright, yet her shoulder blades face upwards like a gorilla's and Selim's fingers are long and curved for climbing trees. Selam's brain poses a further vexing question for science. It appears to have grown slowly - signaling a long childhood. Modern humans use childhood to develop our big brain. All the stuff we learn along the way has to be stored somewhere! Yet Selam had a comparatively small brain. Work that one out! Artifacts it seems, take a while to emerge, while understanding is more elusive - until the book come out! Meanwhile, the Max Planck Society announcement is available at: http://www.maxplanck.de/-snm-0135020272-1120309833-0000019962-0000000000-1120338109-enm-english/illustrationsDocumentation/documentation/pressReleases/2006/pressRelease20060920/index.html

Photo: Mational Museum of Ethiopia