Prof Tanya Smith
Griffith University

Evolution and the Griffith Centre for Social and Cultural Research at Griffith University. She has previously held a professorship at Harvard University and fellowships at the Radcliffe Institute for Advanced Study and the Max Planck Institute for Evolutionary Anthropology. Professor Smith explores the evolution and development of the human dentition. Teeth preserve remarkably faithful records of daily growth and infant diet – as well as stress experienced during birth – for millions of years. Her research has helped to identify of the origins of a fundamental human adaptation: the costly yet advantageous shift from a “live fast and die young” strategy to the “live slow and grow old” strategy that has helped to make us one of the most successful mammals on the planet. Professor Smith’s research has been funded by the Australian Academy of Sciences and the US National Science Foundation, and published in Nature, Proceedings of the National Academy of Sciences, and Science Advances. It has been highlighted in the New York Times, National Geographic, Nature, Science, Smithsonian, and Discovery magazines, as well as through American, Australian, British, Canadian, French, German, Irish, New Zealand, and Singaporean broadcast media.

Abstract

A synchrotron is a machine that produces beams of light from accelerated electrons deviated by magnetic fields. Depending on the energy, the light spectrum may range from radio frequencies to high energy X-rays (hard X-rays). During the past few years, non-destructive synchrotron X-ray microtomographic studies have revealed the internal structure of paleontological and biological samples with a quality far exceeding other virtual methods. The rise of phase contrast synchrotron imaging has created a revolution in non-destructive investigations of fossil samples, including the identification of insects trapped in opaque amber, 3D imaging of embryonic fossils, and novel insights into ancient bone and tooth structure. Beyond documenting novel aspects of vertebrate paleobiology, this “virtual histology” approach has direct relevance for assessing biomedical interventions, particularly with the advent of tissue engineering, stem cell bone graft treatments, and 3D printing technologies.

Here we demonstrate the efficacy of synchrotron imaging and review recent applications in evolutionary anthropology and biology. This includes investigations of developmental features in teeth, including daily growth lines that can be recovered from hominin fossils that are millions of year old. One of the most exciting applications is the non-destructive detection of the neonatal (birth) line, allowing precise age estimates for ancient children, including the oldest-known infant in the hominin fossil record. These studies have provided the earliest evidence of the modern human life history (developmental) pattern in a 300,000 year old early Homo sapiens individual from Morocco, and allowed assessments of brain size and development in early hominins, australopithecines, and Neanderthals. Synchrotron imaging has helped to establish that human uniqueness is the product of a mosaic of anatomical changes over the past seven million years of our evolutionary history.

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