More holistic approach needed when studying the diets of our ancestors

Researchers have long debated how and what our ancestors ate. Charles Darwin hypothesized that the hunting of game animals was a defining feature of early hominids, one that was linked with both upright walking and advanced tool use and that isolated these species from their closest relatives (such as ancestors of chimpanzees); modified versions of this hypothesis exist to this day. Other scholars insist that while our ancestors’ diets did include meat, it was predominantly scavenged and not hunted. Still others argue that particular plant foods such as roots and tubers were of greater importance than meat in the diets of these species.

Research technology has come a long way since Darwin’s time, making possible the kind of analysis early scholars could only have imagined. Recent work has presented reconstructions of early hominid diets on the basis of chemical makeups of fossil tooth enamel, evidence of microscopic wear on teeth, and advanced studies of craniodental anatomy, to name a few.

However, according to Ken Sayers (Georgia State University) and C. Owen Lovejoy (Kent State University) in an article published in the December 2014 issue of The Quarterly Review of Biology, although modern-day technology provides valuable insight, such tools alone cannot provide a complete picture of the diet of early hominids. Instead, they should be included–alongside other methodologies–in holistic studies grounded in the fundamentals of modern evolutionary ecology.

Sayers and Lovejoy suggest that researchers should examine a species’ particular habitat and “whole-body” anatomy, including digestion, locomotion, and possible cognitive abilities. In particular, foraging theory–a branch of evolutionary ecology that investigates animal feeding decisions through the lens of efficiency principles–is especially important to consider, as it demonstrates that diet is regulated by the potential value and costs of exploiting individual food items (whether plant, animal, or other) and by the relative abundance of the most profitable foods. In the case of the earliest-known hominids, evidence about their morphology and likely cognitive abilities–in addition to data obtained from modern technologies–provide little support for a reliance on any one particular food type. Rather, these species likely had a broadly omnivorous diet that became increasingly generalized over time.

According to Sayers and Lovejoy, the early hominid diet can best be elucidated by considering the entire habitat-specific resource base and by quantifying the potential profitability and abundance of likely available foods. Furthermore, they warn that hypotheses focusing too narrowly on any one food type or foraging strategy–such as hunting or scavenging or any one particular plant category–are too restrictive and should be viewed with caution. Modeling these species’ diets instead “requires a holistic, interdisciplinary approach that goes beyond merely what we can observe chemically or through a microscope, and draws from ecology, anatomy and physiology, cognitive science, and behavior.”

Ken Sayers and C. Owen Lovejoy, “Blood, Bulbs, and Bunodonts: On Evolutionary Ecology and the Diets of Ardipithecus, Australopithecus, and Early Homo.” The Quarterly Review of Biology vol. 89, no. 4 (December 2014); pp. 319-357. http://www.jstor.org/stable/10.1086/678568

Oldest horned dinosaur species in North America found in Montana

This is a fossil skull of Aquilops americanus. – Andrew A. Farke

Scientists have named the first definite horned dinosaur species from the Early Cretaceous in North America, according to a study published December 10, 2014 in the open-access journal PLOS ONE by Andrew Farke from Raymond M. Alf Museum of Paleontology and colleagues.

The limited fossil record for neoceratopsian–or horned dinosaurs–from the Early Cretaceous in North America restricts scientists’ ability to reconstruct the early evolution of this group. The authors of this study have discovered a dinosaur skull in Montana that represents the first horned dinosaur from the North American Early Cretaceous that they can identify to the species level. The authors named the dinosaur Aquilops americanus, which exhibits definitive neoceratopsian features and is closely related to similar species in Asia. The skull is comparatively small, measuring 84 mm long, and is distinguished by several features, including a strongly hooked rostral bone, or beak-like structure, and an elongated and sharply pointed cavity over the cheek region. When alive, the authors estimate it was about the size of a crow.

This discovery, combined with neoceratopsian fossil records from elsewhere, allows the authors to support a late Early Cretaceous (~113-105 million years ago) intercontinental migratory event between Asia and North America, as well as support for a complex set of migratory events for organisms between North America and Asia later in the Cretaceous. However, to better reconstruct the timing and mode of these events, additional fieldwork will be necessary.

“Aquilops lived nearly 20 million years before the next oldest horned dinosaur named from North America,” said Andrew Farke. “Even so, we were surprised that it was more closely related to Asian animals than those from North America.”

Reference: http://dx.plos.org/10.1371/journal.pone.0112055

Citation: Farke AA, Maxwell WD, Cifelli RL, Wedel MJ (2014) A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America, and the Biogeography of Neoceratopsia. PLoS ONE 9(12): e112055. doi:10.1371/journal.pone.0112055

Ancient engravings rewrite human history

This is Dr Stephen Munro at the School of Anthropology and Archaeology at ANU. – Phil Dooley, ANU

An international team of scientists has discovered the earliest known engravings from human ancestors on a 400,000 year-old fossilised shell from Java.

The discovery is the earliest known example of ancient humans deliberately creating pattern.

“It rewrites human history,” said Dr Stephen Munro from School of Archaeology and Anthropology at The Australian National University (ANU).

“This is the first time we have found evidence for Homo erectus behaving this way,” he said.

The newly discovered engravings resemble the previously oldest-known engravings, which are associated with either Neanderthals or modern humans from around 100,000 years ago.

The early date and the location of the discovery in Java discount the possibility that the engravings could have been the work of Neanderthals or modern humans.

“It puts these large bivalve shells and the tools used to engrave them, into the hands of Homo erectus, and will change the way we think about this early human species,” Dr Munro said.

It is unclear whether the pattern was intended as art or served some practical purpose.

The zig-zag pattern engravings were only recently discovered on fossilised mussel shells, which had been collected 100 years ago.

Dr Munro visited the Netherlands to study the collection, gathered by the discoverer of Homo erectus, Eugene Dubois, in Java in the late 19th Century.

However, he did not notice the markings on the fossils until he examined photographs he had taken, once back at ANU.

“It was a eureka moment. I could see immediately that they were man-made engravings. There was no other explanation,” Dr Munro said.

Following the discovery, an international team worked to establish the exact date of the shell, using two different methods to arrive at the final result of between 430,000 and 540,000 years old.

The team found that Homo erectus opened the shells by drilling a hole through the shell with a shark’s tooth, exactly at the point where the muscle is attached. Damaging muscles this way causes the valves of the shell to open, so that the contents can be eaten.

“It’s evidence that Homo erectus exploited these aquatic food resources, and fits with other evidence that they probably foraged in and around water,” Dr Munro said.

Click on this image to view the .mp4 video

Dr. Stephen Munro explains how 400,000 year old patterns scratched on a mussel shell have rewritten human history. – ANU multimedia team

What quails can teach us about the gait of dinosaurs

Dr. Emanuel Andrada from the University in Jena (Germany) analyzed the effect of birds posture on the movement of their legs and on their stability when they walk. – Jan-Peter Kasper/FSU

Dinosaurs did it. Human beings and monkey do it. And even birds do it. They walk on two legs. And although humans occupy a special position amongst mammals as they have two legs, the upright gait is not reserved only for man. In the course of evolution many animals have developed the bipedal gait – the ability to walk on two legs.

“Birds are moving forward on two legs as well, although they use a completely different technique from us humans,” Dr. Emanuel Andrada from the Friedrich Schiller University in Jena (Germany) says. Human beings keep their upper bodies generally in an upright position and the body’s center of gravity is directly above the legs. The bodies of birds on the other hand are horizontally forward-facing, which appears to be awkward at first glance. Hence the motion scientist analyzed – together with colleagues – which effect this posture has on the movement of their legs and on their stability when they walk. The first detailed analysis of its kind has now been published by the scientists in the “Proceedings of the Royal Society B” (DOI: 10.1098/rspb.2014.1405).

To this end the team had quails walking through a high speed X-ray installation at varying speeds. While the installation monitored the movements of the animals meticulously, the scientists were able to measure the power at work in their legs. From this data, the Jena research team could develop a computer model of the whole motion sequence, which served to simulate and analyze the stability and the energy balance in connection to different gaits.

As it turned out, the birds use the so-called “grounded running” style when they move quickly – this is a running style in which at least one leg is always touching the ground. “Even when running quickly, short periods of flight phases occur only very rarely between the individual steps,” Prof. Dr. Reinhard Blickhan, Chair of Motion Science at Jena University explains. But this is extremely energy consuming for the animals because the body’s center of gravity lies distinctly in front of their legs – due to the horizontal posture. “The animals have to constantly balance out their own bodies in order to prevent falling forwards,” says Blickhan.

But this huge effort is worthwhile as the researchers discovered with the help of their computer model. “Unlike the legs of humans which gather energy like two coil springs and use it directly to move forwards, the bird’s legs work in addition like dampers or shock absorbers.” In order to prevent falling forwards or to permanently accelerate their movement, the birds practically have to brake all the time. This happens while the bird leg is working like a spring damper: Energy is hereby withdrawn from the leg, but the amount of energy is the same that was invested in the hip to stabilize the trunk via the turning moment.

“This apparent wasting of energy is the price for a very stable posture during locomotion, especially on an uneven terrain,” Blickhan summarizes the result of this study.

After these newly presented results, the Jena researchers anticipate interesting times ahead. They also want to test the gait of other birds with the help of the computer model they developed. And the scientists even want to analyze the locomotion of dinosaurs – the direct forebears of today’s birds. “It is not clear yet how two-legged species like Allosaurus or Tyrannosaurus Rex really moved forward,” says Dr. Andrada. But it is assumed by now that they also ran with their upper bodies thrust forwards horizontally – due to biomechanical advantages.

Original-Publication:

Andrada E. et al.: Trunk orientation causes asymmetries in leg function in small bird terrestrial locomotion. Proceedings of the Royal Society B 2014, DOI: 10.1098/rspb.2014.1405

Scientists reveal parchment’s hidden stories

This is an imaged parchment document from Yarburgh Muniments Lancashire Deeds YM. D. Lancs Jan. 13-14, 1576/7. – By permission of The Borthwick Institute for Archives’.

Millions of documents stored in archives could provide scientists with the key to tracing agricultural development across the centuries, according to new research completed at Trinity College Dublin and the University of York.

Amazingly, thanks to increasingly progressive genetic sequencing techniques, the all-important historical tales these documents tell are no longer confined to their texts; now, vital information also comes from the DNA of the parchment on which they are written.

Researchers used these state-of-the-art scientific techniques to extract ancient DNA and protein from tiny samples of parchment from documents from the late 17th and late 18th centuries. The resulting information enabled them to establish the type of animals from which the parchment was made, which, when compared to genomes of their modern equivalents, provides key information as to how agricultural expansion shaped the genetic diversity of these animals.

This information therefore gives the scientists an unrivalled resource to analyse the development of livestock husbandry across the centuries. The research has just been published in the international, peer-reviewed journal Philosophical Transactions of the Royal Society B.

Professor of Population Genetics at Trinity College Dublin, Daniel Bradley, said: “This pilot project suggests that parchments are an amazing resource for genetic studies that consider agricultural development over the centuries. There must be millions stored away in libraries, archives, solicitors’ offices and even in our own attics. After all, parchment was the writing material of choice for thousands of years, going back to the Dead Sea Scrolls.”

He added: “Wool was essentially the oil of times gone by, so knowing how human change affected the genetics of sheep through the ages can tell us a huge amount about how agricultural practices evolved.”

To conduct their research, geneticists at Trinity extracted DNA from two tiny (2x2cm) samples of parchment provided by the University of York’s Borthwick Institute for Archives. Meanwhile, researchers in the Centre for Excellence in Mass Spectrometry at York extracted collagen (protein) from the same parchment samples.

The first sample showed a strong affinity with northern Britain, specifically the region in which black-faced breeds such as Swaledale, Rough Fell and Scottish Blackface are common, whereas the second sample showed a closer affinity with the Midlands and southern Britain where the livestock Improvements of the later 18th century were most active.

If other parchments show similar levels of DNA content, resulting sequencing could provide insights into the breeding history of livestock – particularly sheep – before, during and after the agricultural improvements of the 18th century that led to the emergence of regional breeds of sheep in Britain.

Professor Matthew Collins, of the Department of Archaeology at York, who heads the University’s BioArCh research centre, said: “We believe the two specimens derive from an unimproved northern hill-sheep typical in Yorkshire in the 17th century, and from a sheep derived from the ‘improved’ flocks, such as those bred in the Midlands by Robert Bakewell, which were spreading through England in the 18th century. We want to understand the history of agriculture in these islands over the last 1,000 years and, with this breath-taking resource, we can.”

###

The research was funded by a grant from the European Research Council. The paper can be viewed here after embargo: http://rstb.royalsocietypublishing.org/content/370/1660.toc

Media Contact:

Daniel Bradley, Professor of Population Genetics, Trinity College Dublin, at dbradley@tcd.ie, or Tel: +353-87-207-9451

Thomas Deane, Press Officer for the Faculty of Engineering, Mathematics, and Science, Trinity College Dublin, at deaneth@tcd.ie, or Tel: +353-1-896-4685

Matthew Collins, Professor of Archaeology, University of York, at matthew.collins@york.ac.uk, or Tel: +44-7955-888101

David Garner, Head of Media Relations, University of York, at david.garner@york.ac.uk or Tel: +44-1904-322153

Parchment a Huge Reservoir of DNA Information

Before the mass production of paper, parchment was the major medium for legal documents and until the widespread adoption of typewriters, they were a clerk’s preferred medium for many formal legal documents and records.

Parchment has a number of properties that make it compelling material for DNA extraction and analysis. Parchments are made from the skins of domestic animals, particularly livestock, and their manufacture results in robust artefacts, which can survive intact for many centuries.

Secondly, they are abundant and because of their enduring legal value they have generally been carefully managed. In the 20th century, this has included protecting them from both high temperatures and fluctuating humidity.

Thirdly, unlike bone remains, of which only a small percentage have been excavated, parchments are above ground, archived and in the case of legal documents, directly related to specific dates – a level of resolution largely unachievable with any other historic DNA source. Even undated documents can be dated palaeographically to a resolution better and more cheaply than radiocarbon dating.