UQ researcher unlocks two-million-year-old lifestyle
Plant and animal residues on ancient tools have revealed facts about the way our ape-like ancestors lived two million years ago.
Before the molecular archaeological techniques developed by the University of Queensland's Dr Tom Loy, researchers knew about the physical characteristics of our distant relatives, known as hominids, but could only speculate on cultural and social aspects of their lives.
The residues examined by Dr Loy are almost 10 times older than the oldest residues previously seen using the DNA analysis techniques he has pioneered since 1979. Dr Loy is the only real life scientist mentioned in the book Jurassic Park.
He was also the first archaeologist in the world to analyse blood residues on the tools of the 5300-year-old Iceman - a frozen body found 3000 metres above sea-level in the Alps near the Austro-Italian border five years ago.
Principal research fellow with both the University's Anthropology and Sociology Department and the Centre for Molecular and Cellular Biology (CMCB), Dr Loy said his current research suggested there was no time limit on the ape/human tools and artefacts which could now be examined for residues.
The first tool-making and tool-using hominids walked the Earth around two million years ago, standing 1.4 metres tall and resembling chimpanzees more than modern-day human beings. Footprints trapped in volcanic ash also reveal they operated in family groups.
While visiting the University of Witwatersrand in South Africa late last year, Dr Loy was presented with 60 tools for residue analysis by Dr Kathy Kuman, chief archaeologist from the Sterkfontein Cave dig, 60kms north-west of Johannesburg.
Dr Loy has since used the state-of-the-art facilities at three University of Queensland research centres to examine starch grains, plant and animal (muscle and collagen) tissue and blood molecules embedded on the tools.
Around 2000 tools have so far been excavated from the dig, mainly sharp flakes of white quartz ranging in size from an adult thumbnail to around nine-centimetres-long. The tools are thought to be processing tools used for tasks such as disjointing meat or cutting up plants.
Dr Loy said his analysis had the potential to reveal many facts about the hominids' way of life. For example, starch grains on the tools emanated from at least three plant types that may have been located in patches or were edible only at certain times of the year.
"This tells us the hominids would have had a certain degree of forward planning in order to harvest these plants suggesting a more complex social organisation than previously thought," he said.
Another new fact defying previous speculation about the lives of hominids had emerged from analysis of blood residues on the tools.
Dr Loy said scientists previously believed the hominids were scavengers, eating meat once it had been picked over by big cats, vultures and hyenas.
However, his research had revealed fresh blood and tissue on the tools, suggesting the hominids had trapped or killed prey themselves, possibly using fire-sharpened sticks. Modern Central African chimpanzees regularly hunt and eat smaller monkey species.
Masters student Paul Kajeski is assisting Dr Loy with his analysis while honours student Peta-Jane Jones is working on a spin-off project investigating possible chemical or geological reasons for the preservation of materials on the tools for such a vast period of time.
Dr Loy said his previous research suggested residues such as blood were preserved from the moment they dried on the ends of tools or weapons. "Molecules unravel to form a matrix which blocks out microbes and water then once the artefact is in the soil, clay interacts with blood proteins to form a further barrier to degradation," he said.
To examine the tools, Dr Loy is using optical microscopy in the University's CMCB laboratories for the starch and plant and animal tissue work while to study blood residues, he is working with Dr Judy Halliday from the University's Centre for Drug Design and Development.
Dr Philippa Unwins from the Centre for Microscopy and Microanalysis is assisting with environmental scanning using an electron microscope for examining collagen and hairs.
Dr Loy said the next step would be to determine exactly what animals and plants comprised the hominid diet. Comparing the tools discovered at the site with other hominid digs in Africa would reveal facts such as tool manufacturing sequences and whether the groups worked side-by-side or individually, he said.
For more information, contact Dr Loy (telephone 07 3365 2326, 07 3365 4391 or mobile 0416 082 939).
