The Royal Society of Victoria annually awards four competitive prizes to final year PhD students in all areas of the Biomedical & Health Sciences, Biological Sciences (Non-human), Earth Sciences, and Physical Sciences. In September 2023, we heard from this year’s eight finalists about their brilliant work in these fields. Over the coming months, they will share a written summary of their presentations in Science Victoria.
Where do we come from and when? The mystery behind the oldest child
By Dr. Wenjing Yu MRSV
RSV Young Scientist Research Prizes (Earth Sciences) – 1st place winner
Let’s travel back in time, about a million years ago. This story is about a boy – a very, very young boy. He died when he was only three, and part of his body was carried by an eagle and dropped off at the Cradle of Humankind in South Africa. He died millions of years ago, making him the ‘oldest child’ in the world. In 1924, his skull was found by quarrymen in a limestone quarry, now known as the Taung Skull Fossil Site. The skull – and the boy it belonged to – was named the “Taung Child”.
This discovery threw a spanner into the works in the field of human evolution research. Before, the theory of human origin had been largely Eurocentric, assuming the rise of humankind occurred in Europe or Eurasia. But this single fossil suggested otherwise.
This fossil was clearly more ancient than earlier finds and Australian anatomist Raymond Dart, who first analysed it, claimed it was a human ancestor. He classified it as an extinctspecies of australopithecine (an entirely new genus) called Australopithecus africanus, the “southern ape from Africa”.1 Scientists were initially reluctant to accept that the Taung Child and the new genusAustralopithecus were ancestral relatives of modern humans – most believed the skull to be from a non-human ape.
It has been almost 100 years since the discovery of the Taung Child, but the A.africanus lineage evolution still remains in question. Where does it belong on the human – or hominin – family tree?
The question has been difficult to answer because we lack sufficient dating evidence at the Taung site. The unique and complicated rock deposits at the discovery site makes fauna fossil dating very difficult.2,3 Making sense of the relationship of different hominin species in South Africa has always been challenging, largely because of issues dating them accurately.
While the question remains open, the Taung Child itself cannot be used in analyses. It is now protected under the South African Heritage Resources Act and must remain untouched. However, 36 years ago, mammal teeth were also collected in the same layer of rock at the Taung site where the skull was found, meaning that we can assume that they are around the same age. They would, in theory, provide us with the approximate age of the Taung Child.
For the first time in history, we can now directly date these mammal teeth using a combination of technologies. I optimised this method during my PhD, allowing me to date the enamel of teeth older than 3 million years old.4,5 This method has provided two possible age models. If the first model is correct, then the Taung Child skull and A. africanusspecies could be older than originally suggested, older than 3.33 million years ago and older than the skeleton that is largely regarded as the first human, ‘Lucy’ (A. afarensis). If the second model is correct, Taung Child’s age would be within 3 Ma.
It is not possible to decide which model is more accurate – yet – but investigations of human evolution will continue. The methodology that I developed will allow researchers to better understand human evolution as we endeavour to answer: where or when do we come from?
Dart, R.A. (1925). Australopithecus africanus the man-ape of South Africa. Nature Publishing Group.
Kuhn, B.F., et al. (2016). Renewed investigations at Taung; 90 years after Australopithecus africanus. Palaeontologia africana51:10–26.
McKee, J.K. (1993). Faunal dating of the Taung hominid fossil deposit. Journal of Human Evolution25(5):363–376.
Yu, W., et al. (2022). Using X-rays as an irradiation source for direct ESR dating of fossil teeth. Quaternary Geochronology72:101372.
Yu, W., et al. (2022). ESRfrag: A new suite of open access programs for the efficient handling of Electron Spin Resonance spectra of enamel fragments. Quaternary Geochronology 71:101335.
We are a registered charity and donations to the Royal Society of Victoria in support of our programs are tax deductible in Australia. We welcome your support! Donate
Work with Us
The Royal Society of Victoria is a Certified Social Enterprise. Our services range from scientific panel and awards program administration to venue hire, events and conference management. We welcome opportunities to work with you.
Community Science Engagement – Inspiring Victoria
Open Access Science: the Proceedings of the RSV
Tours of the RSV’s Hall
We are a small and very busy organisation. Our historic building is not open to the public, but we offer guided tours on Thursdays between 12.30 and 1.30pm (except during Public Holidays and the Christmas/New Year close), depending on prevailing conditions. Please ring ahead to confirm: 9663 5259.